NYU Health Sciences Libraries Faculty Bibliography

Martin J Blaser

School of Medicine. Medicine. Translational Medicine; Microbiology. Muriel G. and George W. Singer Professor of Translational Medicine and Professor of Microbiology, 2000-
  1. Blaser, Martin J. Missing microbes : how the overuse of antibiotics is fueling our modern plagues. New York : Henry Holt and Company, 2014. 273 pages : illustrations ; 25 cm.   First edition    

    This is a look at the harmful effects of overusing antibiotics, from the field's leading expert. Tracing one scientist's journey toward understanding the crucial importance of the microbiome, it takes readers to the forefront of trail-blazing research while revealing the damage that overuse of antibiotics is doing to our health: contributing to the rise of obesity, asthma, diabetes, and certain forms of cancer. Here the author invites us into the wilds of the human microbiome where for hundreds of thousands of years bacterial and human cells have existed in a peaceful symbiosis that is responsible for the health and equilibrium of our body. Now, this invisible eden is being irrevocably damaged by some of our most revered medical advances, antibiotics, threatening the extinction of our irreplaceable microbes with terrible health consequences. Taking us into both the lab and deep into the fields where these troubling effects can be witnessed firsthand, the author not only provides cutting edge evidence for the adverse effects of antibiotics, he tells us what we can do to avoid even more catastrophic health problems in the future. -- Provided by publisher
  2. Gonzalez, M. E.; Schaffer, J. V.; Orlow, S. J.; Gao, Z.; Li, H.; Alekseyenko, A. V.; Blaser, M. J.. "The cutaneous microbiota in atopic dermatitis changes with topical corticosteroid and bleach bath treatment [Meeting Abstract]". Journal of investigative dermatology. 2014 MAY;134 1 1:S109-S109 (ISI:000334560400622 #997122)    
  3. Hecht, Gail A; Blaser, Martin J; Gordon, Jeffrey; Kaplan, Lee M; Knight, Rob; Laine, Loren; Peek, Richard; Sanders, Mary Ellen; Sartor, Balfour; Wu, Gary D; Yang, Vincent W. "What Is the Value of a Food and Drug Administration Investigational New Drug Application for Fecal Microbiota Transplantation to Treat Clostridium difficile Infection? [Editorial]". Clinical Gastroenterology & Hepatology. 2014 Feb;12(2):289-291 (MEDL:24148361 #753942)       
  4. Kienesberger, Sabine; Sprenger, Hanna; Wolfgruber, Stella; Halwachs, Bettina; Thallinger, Gerhard G; Perez-Perez, Guillermo I; Blaser, Martin J; Zechner, Ellen L; Gorkiewicz, Gregor. "Comparative Genome Analysis of Campylobacter fetus Subspecies Revealed Horizontally Acquired Genetic Elements Important for Virulence and Niche Specificity". PLoS ONE. 2014;9(1):e85491-e85491 (e85491) (MEDL:24416416 #741182)       

    Campylobacter fetus are important animal and human pathogens and the two major subspecies differ strikingly in pathogenicity. C. fetus subsp. venerealis is highly niche-adapted, mainly infecting the genital tract of cattle. C. fetus subsp. fetus has a wider host-range, colonizing the genital- and intestinal-tract of animals and humans. We report the complete genomic sequence of C. fetus subsp. venerealis 84-112 and comparisons to the genome of C. fetus subsp. fetus 82-40. Functional analysis of genes predicted to be involved in C. fetus virulence was performed. The two subspecies are highly syntenic with 92% sequence identity but C. fetus subsp. venerealis has a larger genome and an extra-chromosomal element. Aside from apparent gene transfer agents and hypothetical proteins, the unique genes in both subspecies comprise two known functional groups: lipopolysaccharide production, and type IV secretion machineries. Analyses of lipopolysaccharide-biosynthesis genes in C. fetus isolates showed linkage to particular pathotypes, and mutational inactivation demonstrated their roles in regulating virulence and host range. The comparative analysis presented here broadens knowledge of the genomic basis of C. fetus pathogenesis and host specificity. It further highlights the importance of surface-exposed structures to C. fetus pathogenicity and demonstrates how evolutionary forces optimize the fitness and host-adaptation of these pathogens.
  5. Lebwohl, Benjamin; Blaser, Martin J; Ludvigsson, Jonas F; Green, Peter H; Rundle, Andrew; Sonnenberg, Amnon; Genta, Robert M. "THE AUTHORS REPLY". American journal of epidemiology. 2014 Apr;:399-403 (MEDL:24699781 #894812)       
  6. Lee, Soo Ching; Tang, Mei San; Lim, Yvonne A L; Choy, Seow Huey; Kurtz, Zachary D; Cox, Laura M; Gundra, Uma Mahesh; Cho, Ilseung; Bonneau, Richard; Blaser, Martin J; Chua, Kek Heng; Loke, P'ng. "Helminth colonization is associated with increased diversity of the gut microbiota". PLoS neglected tropical diseases. 2014 May;8(5):e2880-e2880 (e2880) (MEDL:24851867 #1012992)       

    Soil-transmitted helminths colonize more than 1.5 billion people worldwide, yet little is known about how they interact with bacterial communities in the gut microbiota. Differences in the gut microbiota between individuals living in developed and developing countries may be partly due to the presence of helminths, since they predominantly infect individuals from developing countries, such as the indigenous communities in Malaysia we examine in this work. We compared the composition and diversity of bacterial communities from the fecal microbiota of 51 people from two villages in Malaysia, of which 36 (70.6%) were infected by helminths. The 16S rRNA V4 region was sequenced at an average of nineteen thousand sequences per samples. Helminth-colonized individuals had greater species richness and number of observed OTUs with enrichment of Paraprevotellaceae, especially with Trichuris infection. We developed a new approach of combining centered log-ratio (clr) transformation for OTU relative abundances with sparse Partial Least Squares Discriminant Analysis (sPLS-DA) to enable more robust predictions of OTU interrelationships. These results suggest that helminths may have an impact on the diversity, bacterial community structure and function of the gut microbiota.
  7. Maldonado-Contreras, A; Mane, SP; Zhang, X-S; Pericchi, L; Alarcon, T; Contreras, M; Linz, B; Blaser, MJ; Dominguez-Bello, MG. "Erratum: Phylogeographic evidence of cognate recognition site patterns and transformation efficiency differences in H. pylori: Theory of strain dominance [Erratum]". BMC microbiology. 2014;14(1):- (122) (SCOPUS:2-s2.0-84901983040 #1062322)       
  8. Maldonado-Contreras, Ana; Mane, Shrinivasrao P; Zhang, Xue-Song; Pericchi, Luis; Alarcon, Teresa; Contreras, Monica; Linz, Bodo; Blaser, Martin J; Dominguez-Bello, Maria Gloria. "Correction: Phylogeographic evidence of cognate recognition site patterns and transformation efficiency differences in H. pylori: theory of strain dominance". BMC microbiology. 2014;14(1):122-122 (MEDL:24885618 #1030662)       
  9. Ruiz, V; Gottwick, C; Livanos, A; Li, H; Blaser, M. "Understanding the effect of early-life pulsed antibiotic treatment on mucosal T-lymphocyte populations [Meeting Abstract]". Journal of immunology. 2014 01 May 2014;192(1):- (EMBASE:71473486 #1058312)      

    Broad-spectrum antibiotics are frequently prescribed for children. The gut microbiota have functional roles in the development and differentiation of the host immune system. Early-life antibiotic use may have dynamic effects on the host microbiota, promoting long-term immunologic dysregulation and subsequent allergic and autoimmune pathology. Using a model of early-life antibiotic use, we hypothesize that early-life pulsed antibiotic treatment (PAT) -induced perturbation of the intestinal microbiota leads to alterations in tissue-specific and systemic T-cell populations. To test this hypothesis, we characterized splenic and ileal T-cell populations in control and PAT-treated C57BL/6 mice. Flow cytometric analysis demonstrated that early-life PAT significantly (p<0.05) decreased the frequency of splenic CD4+ and CD8+ T-cells and ileal CD4+ IL-17A+ Th17 populations. In contrast, ileal CD4+ Tbet+ (Th1) T cells and CD4+ Foxp3+ regulatory T-cell populations were significantly increased in PAT-treated mice. Alterations in immune cell populations were associated with microbial compositional changes, including significantly higher relative abundance of Enterobacteriaceae and Akkermansia muciniphila in PAT-treated mice. These results provide evidence that early-life perturbation of the intestinal microbiota by PAT modulates systemic and mucosal T-cell populations, phenotypes that may persist after microbial recovery, promoting life-long consequences to host immunity
  10. Segal, Leopoldo N; Alekseyenko, Alexander V; Clemente, Jose C; Kulkarni, Rohan; Wu, Benjamin; Gao, Zhan; Chen, Hao; Berger, Kenneth I; Goldring, Roberta M; Rom, William N; Blaser, Martin J; Weiden, Michael D. "Correction: Enrichment of lung microbiome with supraglottic taxa is associated with increased pulmonary inflammation". Microbiome. 2014;2:21-21 (MEDL:24991408 #1065932)       

    [This corrects the article on p. 19 in vol. 1, PMID: 24450871.].
  11. Segal, Leopoldo N; Alekseyenko, Alexander; Clemente, Jose C; Berger, Kenneth; Goldring, Roberta; Rom, William N; Blaser, Martin J; Weiden, Michael D. "Enrichment of lung microbiome with supraglotic microbes is associated with increased pulmonary inflammation". Annals of the American Thoracic Society. 2014 Jan;11 Suppl 1:S71-S71 (S71) (MEDL:24437413 #753802)       

    Oral flora are frequently found in normal individuals' lungs without known harm. We hypothesize that a lung microbiome enriched by oral taxa would be associated with a higher degree of inflammation. We studied 29 asymptomatic subjects (9 nonsmokers and 20 smokers) with preserved lung function. Nasal bronchoscopy was performed with two separate bronchoscopes to retrieve supraglotic and lower airway samples. Bronchoalveolar lavage (BAL) cell count, BAL cytokines (Luminex), and exhaled nitric oxide defined pulmonary inflammation. Quantitative PCR measured 16S rRNA gene concentration and 454 sequences defined the microbiome. Supraglotic samples had the highest 16S rRNA concentration, BAL was intermediate, and saline used for the BAL had the lowest concentration. Nonsmokers and smokers were similar in BAL cell differential and lung microbiome. BAL samples segregated into two distinct groups that we called pneumotypes. Pneumotype background predominant taxa (pneumotypeBPT) was similar to the saline background in rDNA concentration or microbial community. Pneumotype supraglotic-characteristic taxa (pneumotypeSCT) has higher rDNA concentration and high relative abundance of SCT, such as Prevotella and Veillonella. PneumotypeSCT was associated with multiple measures of lung inflammation, including higher BAL neutrophils, IL-8, and levels of exhaled nitric oxide. PneumotypeSCT also had higher BAL lymphocytes and fractalkine, a chemokine that correlates with T helper type 17:T regulatory cell ratio in the BAL. These data suggest that a pneumotype with high relative abundance of supraglotic bacteria, such as Prevotella and Veillonella, is associated with increased innate and cellular inflammation.
  12. Segal, Leopoldo N; Blaser, Martin J. "A brave new world: the lung microbiota in an era of change". Annals of the American Thoracic Society. 2014 Jan;11 Suppl 1:S21-S27 (MEDL:24437400 #753922)       

    The development of culture-independent techniques has revolutionized our understanding of how our human cells interact with the even greater number of microbial inhabitants of our bodies. As part of this revolution, data are increasingly challenging the old dogma that in health, the lung mucosa is sterile. To understand how the lung microbiome may play a role in human health, we identified five major questions for lung microbiome research: (1) Is the lung sterile? (2) Is there a unique core microbiome in the lung? (3) How dynamic are the microbial populations? (4) How do pulmonary immune responses affect microbiome composition? and (5) Are the lungs influenced by the intestinal immune responses to the gut microbiome? From birth, we are exposed to continuous microbial challenges that shape our microbiome. In our changing environment, perturbation of the gut microbiome affects both human health and disease. With widespread antibiotic use, the ancient microbes that formerly resided within us are being lost, for example, Helicobacter pylori in the stomach. Animal models show that antibiotic exposure in early life has developmental consequences. Considering the potential effects of this altered microbiome on pulmonary responses will be critical for future investigations.
  13. Wagenaar, Jaap A; van Bergen, Marcel A P; Blaser, Martin J; Tauxe, Robert V; Newell, Diane G; van Putten, Jos P M. "Campylobacter fetus Infections in Humans: Exposure and Disease". Clinical infectious diseases. 2014 Mar;:399-403 (MEDL:24550377 #894802)       

    Campylobacter fetus can cause intestinal illness and, occasionally, severe systemic infections. Infections mainly affect persons at higher risk, including elderly and immunocompromised individuals and those with occupational exposure to infected animals. Outbreaks are infrequent but have provided insight into sources. Source attribution of sporadic cases through case-control interviews has not been reported. The reservoirs for C. fetus are mainly cattle and sheep. Products from these animals are suspected as sources for human infections. Campylobacter fetus is rarely isolated from food, albeit selective isolation methods used in food microbiology are not suited for its detection. We hypothesize that the general population is regularly exposed to C. fetus through foods of animal origin, cross-contaminated foodstuffs, and perhaps other, as yet unidentified, routes. Campylobacter fetus infection should be suspected particularly in patients with nonspecific febrile illness who are immunocompromised or who may have been occupationally exposed to ruminants.
  14. Alekseyenko, Alexander V; Perez-Perez, Guillermo I; De Souza, Aieska; Strober, Bruce; Gao, Zhan; Bihan, Monika; Li, Kelvin; Methe, Barbara A; Blaser, Martin J. "Community differentiation of the cutaneous microbiota in psoriasis". Microbiome. 2013;1(1):31-31 (MEDL:24451201 #760032)       

    BACKGROUND: Psoriasis is a common chronic inflammatory disease of the skin. We sought to characterize and compare the cutaneous microbiota of psoriatic lesions (lesion group), unaffected contralateral skin from psoriatic patients (unaffected group), and similar skin loci in matched healthy controls (control group) in order to discern patterns that govern skin colonization and their relationship to clinical diagnosis. RESULTS: Using high-throughput 16S rRNA gene sequencing, we assayed the cutaneous bacterial communities of 51 matched triplets and characterized these samples using community data analysis techniques. Intragroup Unifrac beta diversity revealed increasing diversity from control to unaffected to lesion specimens. Likewise, principal coordinates analysis (PCoA) revealed separation of the lesion samples from unaffected and control along the first axis, suggesting that psoriasis is a major contributor to the observed diversity. The taxonomic richness and evenness decreased in both lesion and unaffected communities compared to control. These differences are explained by the combined increased abundance of the four major skin-associated genera (Corynebacterium, Propionibacterium, Staphylococcus, and Streptococcus), which present a potentially useful predictor for clinical skin type. Psoriasis samples also showed significant univariate decreases in relative abundances and strong classification performance of Cupriavidus, Flavisolibacter, Methylobacterium, and Schlegelella genera versus controls. The cutaneous microbiota separated into two distinct clusters, which we call cutaneotypes: (1) Proteobacteria-associated microbiota, and (2) Firmicutes-associated and Actinobacteria-associated microbiota. Cutaneotype 2 is enriched in lesion specimens compared to control (odds ratio 3.52 (95% CI 1.44 to 8.98), P <0.01). CONCLUSIONS: Our results indicate that psoriasis induces physiological changes both at the lesion site and at the systemic level, which select for specific differential microbiota among the assayed clinical skin types. These differences in microbial community structure in psoriasis patients are potentially of pathophysiologic and diagnostic significance.
  15. Blaser, Martin J. "Assigning proper credit". Nature medicine. 2013 Jan;19(1):16-16 (MEDL:23296000 #211492)       
  16. Blaser, Martin J; Dominguez-Bello, Maria G; Contreras, Monica; Magris, Magda; Hidalgo, Glida; Estrada, Isidoro; Gao, Zhan; Clemente, Jose C; Costello, Elizabeth K; Knight, Rob. "Distinct cutaneous bacterial assemblages in a sampling of South American Amerindians and US residents". ISME journal. 2013 Aug;:85-95 (MEDL:22895161 #175981)       

    The human skin harbors complex bacterial communities. Prior studies showing high inter-individual variation focused on subjects from developed countries. We therefore compared cutaneous bacterial communities of Amerindians in the Venezuelan Amazon with subjects in the United States. Forearm skin specimens were studied from healthy Amerindians in Platanillal village in Amazonas State, and from healthy persons in New York and Colorado. All skin sampling used similar swab/buffer techniques. Multiplexed V2-targeted 16S rRNA gene pyrosequencing yielded high quality sequences from 112 samples. The results show 20 phyla, with three (Proteobacteria, Firmicutes, Actinobacteria) predominating. US residents and Venezuelan Amerindians had significantly different forearm skin bacterial community compositions, with United States dominated by Propionibacterium. Among the Amerindians, there was a deep split based on bacterial community membership, with 30 and 42 samples, respectively, falling into each of the two groups, not associated with age, gender, or body mass index. One Amerindian group had diversity similar to the United States, but was dominated by Staphylococcus rather than Propionibacterium. The other Amerindian group was significantly more diverse and even than the US or the other Amerindian group, and featured a broad range of Proteobacteria. The results provide evidence that ethnicity, lifestyle and/or geography are associated with the structure of human cutaneous bacterial communities.The ISME Journal advance online publication, 16 August 2012; doi:10.1038/ismej.2012.81.
  17. Blaser, Martin; Bork, Peer; Fraser, Claire; Knight, Rob; Wang, Jun. "The microbiome explored: recent insights and future challenges". Nature reviews. Microbiology. 2013 Mar;11(3):213-217 (MEDL:23377500 #223222)       

    One of the most exciting scientific advances in recent years has been the realization that commensal microorganisms are not simple 'passengers' in our bodies, but instead have key roles in our physiology, including our immune responses and metabolism, as well as in disease. These insights have been obtained, in part, through the work of large-scale, consortium-driven metagenomic projects. Here, five experts in the field of microbiome research discuss the most surprising and exciting new findings, and outline the future steps that will be necessary to elucidate the numerous roles of the microbiota in human health and disease and to develop viable therapeutic strategies.
  18. Blustein, J; Attina, T; Liu, M; Ryan, A M; Cox, L M; Blaser, M J; Trasande, L. "Association of caesarean delivery with child adiposity from age 6 weeks to 15 years". International journal of obesity & related metabolic disorders. 2013 Apr;:467-476 (MEDL:23670220 #416862)       

    Objectives:To assess associations of caesarean section with body mass from birth through adolescence.Design:Longitudinal birth cohort study, following subjects up to 15 years of age.Setting and participants:Children born in 1991-1992 in Avon, UK who participated in the Avon Longitudinal Study of Parents and Children (ALSPAC) (n=10 219).Outcome measures:Primary outcome: standardized measures of body mass (weight-for length z-scores at 6 weeks, 10 and 20 months; and body mass index (BMI) z-scores at 38 months, 7, 9, 11 and 15 years). Secondary outcome: categorical overweight or obese (BMI >/=85th percentile) for age and gender, at 38 months, 7, 9, 11 and 15 years.Results:Of the 10 219 children, 926 (9.06%) were delivered by caesarean section. Those born by caesarean had lower-birth weights than those born vaginally (-46.1 g, 95% confidence interval(CI): 14.6-77.6 g; P=0.004). In mixed multivariable models adjusting for birth weight, gender, parental body mass, family sociodemographics, gestational factors and infant feeding patterns, caesarean delivery was consistently associated with increased adiposity, starting at 6 weeks (+0.11 s.d. units, 95% CI: 0.03-0.18; P=0.005), through age 15 (BMI z-score increment+0.10 s.d. units, 95% CI: 0.001-0.198; P=0.042). By age 11 caesarean-delivered children had 1.83 times the odds of overweight or obesity (95% CI: 1.24-2.70; P=0.002). When the sample was stratified by maternal pre-pregnancy weight, the association among children born of overweight/obese mothers was strong and long-lasting. In contrast, evidence of an association among children born of normal-weight mothers was weak.Conclusion:Caesarean delivery is associated with increased body mass in childhood and adolescence. Research is needed to further characterize the association in children of normal weight women. Additional work is also needed to understand the mechanism underlying the association, which may involve relatively enduring changes in the intestinal microbiome.International Journal of Obesity advance online publication, 14 May 2013; doi:10.1038/ijo.2013.49.
  19. Chen, Yu; Segers, Stephanie; Blaser, Martin J. "Association between Helicobacter pylori and mortality in the NHANES III study". Gut: journal of the British Society of Gastroenterology. 2013 Jan;:5391-5397 (MEDL:23303440 #416832)       

    OBJECTIVE: Persistent colonisation by Helicobacter pylori, and especially by cagA-positive strains, has been related to several health outcomes with effects in opposite directions. Thus, it is important to evaluate its influence on total and category-specific mortality. DESIGN: We conducted prospective cohort analyses in a nationally representative sample of 9895 participants enrolled in the National Health and Nutrition Examination Survey III to assess the association of H pylori status with all-cause and cause-specific mortality. Analyses for the association of H pylori cagA positivity with mortality were conducted in 7384 subjects with data on H pylori cagA status. RESULTS: In older people (>40.1 years), H pylori was not associated with all-cause mortality (HR 1.00; 95% CI 0.84 to 1.18). There was an inverse association of H pylori status with stroke mortality (HR 0.69; 95% CI 0.44 to 1.08), and the inverse association was stronger for H pylori cagA positivity, with the HR of 0.45 (95% CI 0.27 to 0.76). H pylori was also strongly positively related to gastric cancer mortality. After we adjusted p values using the Benjamini-Hochberg false discovery rate method to account for multiple comparisons, these associations remained, and H pylori status was not related to other outcomes. CONCLUSIONS: Our findings suggest that H pylori has a mixed role in human health, but is not a major risk factor for all-cause mortality.
  20. Cox, Laura M; Blaser, Martin J. "Pathways in microbe-induced obesity". Cell metabolism. 2013 Jun;17(6):883-894 (MEDL:23747247 #408682)       

    Diet, host gene composition, and alterations in the intestinal microbiota can contribute to obesity. In microbe-induced obesity, metabolic changes stem from primary perturbation of the microbiota, consequent to modern changes in human biology. Microbiota disruption during early development can result in syndromes of metabolic dysfunction. We focus on the pathways involved in these interactions, particularly related to energy extraction and the role of inflammation in the metabolic phenotypes. Model physiologic systems and perturbations including gastric bypass surgery, pregnancy, and hibernation provide insight into the respective roles of the critical participants.
  21. Cox, Laura M; Cho, Ilseung; Young, Scott A; Anderson, W H Kerr; Waters, Bartholomew J; Hung, Shao-Ching; Gao, Zhan; Mahana, Douglas; Bihan, Monika; Alekseyenko, Alexander V; Methe, Barbara A; Blaser, Martin J. "The nonfermentable dietary fiber hydroxypropyl methylcellulose modulates intestinal microbiota". FASEB journal. 2013 Feb;27(2):692-702 (MEDL:23154883 #242182)       

    Diet influences host metabolism and intestinal microbiota; however, detailed understanding of this tripartite interaction is limited. To determine whether the nonfermentable fiber hydroxypropyl methylcellulose (HPMC) could alter the intestinal microbiota and whether such changes correlated with metabolic improvements, C57B/L6 mice were normalized to a high-fat diet (HFD), then either maintained on HFD (control), or switched to HFD supplemented with 10% HPMC, or a low-fat diet (LFD). Compared to control treatment, both LFD and HPMC reduced weight gain (11.8 and 5.7 g, respectively), plasma cholesterol (23.1 and 19.6%), and liver triglycerides (73.1 and 44.6%), and, as revealed by 454-pyrosequencing of the microbial 16S rRNA gene, decreased microbial alpha-diversity and differentially altered intestinal microbiota. Both LFD and HPMC increased intestinal Erysipelotrichaceae (7.3- and 12.4-fold) and decreased Lachnospiraceae (2.0- and 2.7-fold), while only HPMC increased Peptostreptococcaceae (3.4-fold) and decreased Ruminococcaceae (2.7-fold). Specific microorganisms were directly linked with weight change and metabolic parameters in HPMC and HFD mice, but not in LFD mice, indicating that the intestinal microbiota may play differing roles during the two dietary modulations. This work indicates that HPMC is a potential prebiotic fiber that influences intestinal microbiota and improves host metabolism.
  22. den Hollander, W J; Holster, I L; den Hoed, C M; van Deurzen, F; van Vuuren, A J; Jaddoe, V W; Hofman, A; Perez, G I Perez; Blaser, M J; Moll, H A; Kuipers, E J. "Ethnicity is a strong predictor for Helicobacter pylori infection in young women in a multi-ethnic European city". Journal of gastroenterology & hepatology. 2013 Jun;:S70-S72 (MEDL:23808840 #416892)       

    BACKGROUND AND AIM: At the same time that H. pylori prevalence is declining in Western countries, immigrants from developing countries with high H. pylori prevalence have settled in Western urban areas. Actual epidemiologic data on H. pylori in a migrant community may help in realizing a more selective approach to assess H. pylori-related diseases. We aimed to define H. pylori prevalence as well as risk groups for H. pylori in a cohort of young women living in a multi-ethnic European city. METHODS: We measured IgG anti-H. pylori and CagA-antibodies in serum of pregnant women included in a population-based prospective cohort study. Information on demographics, and socio-economic status was collected by questionnaires. Chi-square and logistic regression were used. RESULTS: In total, 3146 (46%) of the 6837 tested women (mean age 29.7 +/- 5.3) were H. pylori-positive and 1110 (35%) of them were CagA-positive. The H. pylori prevalence in Dutch women was 24%, which was significantly lower than in non-Dutch women (64%; p<0.001). In particular, H. pylori positivity was found in 92% of Moroccan (OR 19.2; 95% CI 11.8-32.0), 80% of Cape Verdean (7.6; 5.0-11.5), 81% of Turkish (9.0; 6.7-12.1), 60% of Dutch Antillean (3.3; 2.3-4.7), and 58% of Surinamese women (3.0; 2.3-3.8). Among H. pylori-positive Dutch subjects, 19% were CagA-positive compared with 40% of the non-Dutch subjects (p<0.001). CONCLUSIONS: Despite a general trend of declining prevalence in Western countries, H. pylori remains highly prevalent in migrant communities, which may constitute target groups for screening and eradication to prevent H. pylori-related diseases.
  23. den Hollander, W. J.; Holster, I. L.; van Gilst, B.; van Vuuren, A. J.; Jaddoe, V. W.; Perez-Perez, G. I.; Blaser, M. J.; Moll, H. A.; Kuipers, E. J.. "HELICOBACTER PYLORI COLONIZATION RATE IN CHILDREN IS HIGHLY VARIABLE AMONG DIFFERENT ETHNIC GROUPS IN WESTERN POPULATIONS: THE GENERATION R STUDY [Meeting Abstract]". Helicobacter. 2013 SEP;18 1 1(SI):81-81 (ISI:000324047300020 #557522)    
  24. den Hollander, W. J.; Schalekamp-Timmermans, S.; Holster, I. L.; Jaddoe, V. W.; Perez-Perez, G. I.; Blaser, M. J.; Steegers, E. A. P.; Kuipers, E. J.. "HELICOBACTER PYLORI COLONIZATION AND PREECLAMPSIA: THE GENERATION R STUDY [Meeting Abstract]". Helicobacter. 2013 SEP;18 1 1(SI):115-115 (ISI:000324047300132 #557512)    
  25. den Hollander, W. J.; Sonnenschein-Van der Voort, A. M. M.; Holster, I. L.; Duijts, L.; de Jongste, J. C.; Jaddoe, V. W.; Perez-Perez, G. I.; Blaser, M. J.; Moll, H. A.; Kuipers, E. J.. "MATERNAL HELICOBACTER PYLORI COLONIZATION IS NOT ASSOCIATED WITH ASTHMA SYMPTOMS, AIRWAY INFLAMMATION AND AIRWAY RESISTANCE IN THEIR CHILDREN UNTIL THE AGE OF 6 YEARS: THE GENERATION R STUDY [Meeting Abstract]". Helicobacter. 2013 SEP;18 1 1(SI):116-116 (ISI:000324047300134 #557492)    
  26. Den, Hollander, WJ; Holster, IL; den, Hoed, CM; van, Deurzen, F; van, Vuuren, AJ; Jaddoe, VW; Hofman, A; Perez, Perez, GI; Blaser, MJ; Moll, HA; Kuipers, EJ. "Ethnicity is a strong predictor for Helicobacter pylori infection in young women in a multi-ethnic European city". Journal of gastroenterology & hepatology. 2013;28(11):1705-1711 (SCOPUS:2-s2.0-84885974175 #839372)       

    Background and Aim: At the same time that Helicobacter pylori prevalence is declining in Western countries, immigrants from developing countries with high H.pylori prevalence have settled in Western urban areas. Actual epidemiological data on H.pylori in a migrant community may help in realizing a more selective approach to assess H.pylori-related diseases. We aimed to define H.pylori prevalence as well as risk groups for H.pylori in a cohort of young women living in a multi-ethnic European city. Methods: We measured Immunoglobulin G (IgG) anti-H.pylori and CagA-antibodies in serum of pregnant women included in a population-based prospective cohort study, the Generation R study. Information on demographics and socioeconomic status was collected by questionnaires. Chi-square and logistic regression were used. Results: In total, 3146 (46%) of the 6837 tested women (mean age 29.75.3) were H.pylori-positive and 1110 (35%) of them were CagA-positive. The H.pylori prevalence in Dutch women was 24%, which was significantly lower than in non-Dutch women (64%; P<0.001). In particular, H.pylori positivity was found in 92% of Moroccan (odds ratio 19.2; 95% confidence interval 11.8-32.0), 80% of Cape Verdean (7.6; 5.0-11.5), 81% of Turkish (9.0; 6.7-12.1), 60% of Dutch Antillean (3.3; 2.3-4.7), and 58% of Surinamese women (3.0; 2.3-3.8). Among H.pylori-positive Dutch subjects, 19% were CagA-positive compared with 40% of the non-Dutch subjects (P<0.001). Conclusions: Despite a general trend of declining prevalence in Western countries, H.pylori remains highly prevalent in migrant communities, which may constitute target groups for screening and eradication to prevent H.pylori-related diseases.
  27. Frank, Lily E; Blaser, Martin J; Hirschhorn, Kurt; Moros, Daniel A; Rhodes, Matthew E; Philpott, Sean. "The human microbiome: science, history and research" IN: The human microbiome : ethical, legal and social concerns. Oxford ; New York : Oxford University Press, 2013. . p.?-?.  (OCLC:840803662-01 #988662)    
  28. Gilbert, Maarten J; Miller, William G; Yee, Emma; Blaser, Martin J; Wagenaar, Jaap A; Duim, Birgitta. "Complete Genome Sequence of Campylobacter fetus subsp. testudinum Strain 03-427T". Genome announcements. 2013;1(6):?-? (e85491) (MEDL:24336365 #753932)       

    Campylobacter fetus subsp. testudinum has been isolated from reptiles and humans. This Campylobacter subspecies is genetically distinct from other C. fetus subspecies. Here, we present the first whole-genome sequence for this C. fetus subspecies.
  29. Lebwohl, Benjamin; Blaser, Martin J; Ludvigsson, Jonas F; Green, Peter H R; Rundle, Andrew; Sonnenberg, Amnon; Genta, Robert M. "Decreased Risk of Celiac Disease in Patients With Helicobacter pylori Colonization". American journal of epidemiology. 2013 Dec;178(12):1721-1730 (MEDL:24124196 #746592)       

    The prevalence of celiac disease (CD) has increased in recent decades without a clear explanation. The "hygiene hypothesis" theorizes that decreased exposure to bacterial antigens may trigger autoimmunity. We aimed to determine whether Helicobacter pylori infection and CD were associated among patients undergoing upper gastrointestinal endoscopy. We performed a cross-sectional study of patients who underwent esophagogastroduodenoscopy with submission of gastric and duodenal biopsies to Miraca Life Sciences, Inc. (Irving, Texas), a US commercial pathology laboratory, during a 4.5-year period (January 2008-June 2012). We compared the prevalence of H. pylori in CD patients with that in persons without CD. We performed multiple logistic regression analysis, adjusting odds ratios for patient age, gender, and racial, ethnic, and socioeconomic factors. Among 136,179 patients, a total of 2,689 (2.0%) had CD. H. pylori prevalence was significantly lower in patients with CD (4.4%) than in those without CD (8.8%; P < 0.0001). After adjustment for the above covariates, this inverse relationship remained strong (adjusted odds ratio (OR) = 0.48, 95% confidence interval (CI): 0.40, 0.58). The relationships were similar in men (unadjusted OR = 0.51, 95% CI: 0.38, 0.69) and women (unadjusted OR = 0.46, 95% CI: 0.36, 0.58) and in all age groups. We conclude that H. pylori presence and CD are inversely associated, a relationship that persists after adjustment for socioeconomic factors. Future studies should address whether H. pylori modulates immune responses to ingested gluten.
  30. Ledger, Wj; Blaser, Mj. "Are we using too many antibiotics during pregnancy?". BJOG: an International Journal of Obstetrics & Gynaecology. 2013 Nov;120(12):1450-1452 (MEDL:24118809 #611862)       
  31. Maldonado-Contreras, Ana; Mane, Shrinivasrao P; Zhang, Xue-Song; Pericchi, Luis; Alarcon, Teresa; Contreras, Monica; Linz, Bodo; Blaser, Martin J; Dominguez-Bello, Maria Gloria. "Phylogeographic evidence of cognate recognition site patterns and transformation efficiency differences in H. pylori: theory of strain dominance". BMC microbiology. 2013;13:211-211 (MEDL:24050390 #753952)       

    BACKGROUND: Helicobacter pylori has diverged in parallel to its human host, leading to distinct phylogeographic populations. Recent evidence suggests that in the current human mixing in Latin America, European H. pylori (hpEurope) are increasingly dominant at the expense of Amerindian haplotypes (hspAmerind). This phenomenon might occur via DNA recombination, modulated by restriction-modification systems (RMS), in which differences in cognate recognition sites (CRS) and in active methylases will determine direction and frequency of gene flow. We hypothesized that genomes from hspAmerind strains that evolved from a small founder population have lost CRS for RMS and active methylases, promoting hpEurope's DNA invasion. We determined the observed and expected frequencies of CRS for RMS in DNA from 7 H. pylori whole genomes and 110 multilocus sequences. We also measured the number of active methylases by resistance to in vitro digestion by 16 restriction enzymes of genomic DNA from 9 hpEurope and 9 hspAmerind strains, and determined the direction of DNA uptake in co-culture experiments of hspAmerind and hpEurope strains. RESULTS: Most of the CRS were underrepresented with consistency between whole genomes and multilocus sequences. Although neither the frequency of CRS nor the number of active methylases differ among the bacterial populations (average 8.6 +/- 2.6), hspAmerind strains had a restriction profile distinct from that in hpEurope strains, with 15 recognition sites accounting for the differences. Amerindians strains also exhibited higher transformation rates than European strains, and were more susceptible to be subverted by larger DNA hpEurope-fragments than vice versa. CONCLUSIONS: The geographical variation in the pattern of CRS provides evidence for ancestral differences in RMS representation and function, and the transformation findings support the hypothesis of Europeanization of the Amerindian strains in Latin America via DNA recombination.
  32. Marild, Karl; Ye, Weimin; Lebwohl, Benjamin; Green, Peter Hr; Blaser, Martin J; Card, Tim; Ludvigsson, Jonas F. "Antibiotic exposure and the development of coeliac disease: a nationwide case--control study". BMC gastroenterology. 2013 Jul;13(1):109-109 (MEDL:23834758 #421192)       

    BACKGROUND: The intestinal microbiota has been proposed to play a pathogenic role in coeliac disease (CD). Although antibiotics are common environmental factors with a profound impact on intestinal microbiota, data on antibiotic use as a risk factor for subsequent CD development are scarce. METHODS: In this population-based case--control study we linked nationwide histopathology data on 2,933 individuals with CD (Marsh stage 3; villous atrophy) to the Swedish Prescribed Drug Register to examine the association between use of systemic antibiotics and subsequent CD. We also examined the association between antibiotic use in 2,118 individuals with inflammation (Marsh 1--2) and in 620 individuals with normal mucosa (Marsh 0) but positive CD serology. All individuals undergoing biopsy were matched for age and sex with 28,262 controls from the population. RESULTS: Antibiotic use was associated with CD (Odds ratio [OR] = 1.40; 95% confidence interval [CI] = 1.27-1.53), inflammation (OR = 1.90; 95% CI = 1.72--2.10) and normal mucosa with positive CD serology (OR = 1.58; 95% CI = 1.30--1.92). ORs for prior antibiotic use in CD were similar when we excluded antibiotic use in the last year (OR = 1.30; 95% CI = 1.08-1.56) or restricted to individuals without comorbidity (OR = 1.30; 95% CI = 1.16 -- 1.46). CONCLUSIONS: The positive association between antibiotic use and subsequent CD but also with lesions that may represent early CD suggests that intestinal dysbiosis may play a role in the pathogenesis of CD. However, non-causal explanations for this positive association cannot be excluded.
  33. Pantoja-Feliciano, Ida Gisela; Clemente, Jose C; Costello, Elizabeth K; Perez, Maria E; Blaser, Martin J; Knight, Rob; Dominguez-Bello, Maria Gloria. "Biphasic assembly of the murine intestinal microbiota during early development". ISME journal. 2013 Jun;7(6):1112-1115 (MEDL:23535917 #408112)       

    The birth canal provides mammals with a primary maternal inoculum, which develops into distinctive body site-specific microbial communities post-natally. We characterized the distal gut microbiota from birth to weaning in mice. One-day-old mice had colonic microbiota that resembled maternal vaginal communities, but at days 3 and 9 of age there was a substantial loss of intestinal bacterial diversity and dominance of Lactobacillus. By weaning (21 days), diverse intestinal bacteria had established, including strict anaerobes. Our results are consistent with vertical transmission of maternal microbiota and demonstrate a nonlinear ecological succession involving an early drop in bacterial diversity and shift in dominance from Streptococcus to Lactobacillus, followed by an increase in diversity of anaerobes, after the introduction of solid food. Mammalian newborns are born highly susceptible to colonization, and lactation may control microbiome assembly during early development.
  34. Patrick, Mary E; Gilbert, Maarten J; Blaser, Martin J; Tauxe, Robert V; Wagenaar, Jaap A; Fitzgerald, Collette. "Human infections with new subspecies of Campylobacter fetus". Emerging infectious diseases. 2013 Oct;19(10):1678-1680 (MEDL:24050521 #700772)       

    Campylobacter fetus subsp. testudinum subsp. nov. is a newly proposed subspecies of C. fetus with markers of reptile origin. We summarize epidemiologic information for 9 humans infected with this bacterium. All cases were in men, most of whom were of Asian origin. Infection might have been related to exposure to Asian foods or reptiles.
  35. Petschow, Bryon; Dore, Joel; Hibberd, Patricia; Dinan, Timothy; Reid, Gregor; Blaser, Martin; Cani, Patrice D; Degnan, Fred H; Foster, Jane; Gibson, Glenn; Hutton, John; Klaenhammer, Todd R; Ley, Ruth; Nieuwdorp, Max; Pot, Bruno; Relman, David; Serazin, Andrew; Sanders, Mary Ellen. "Probiotics, prebiotics, and the host microbiome: the science of translation". Annals of the New York Academy of Sciences. 2013 Dec;1306(1):1-17 (MEDL:24266656 #712612)       

    Recent advances in our understanding of the community structure and function of the human microbiome have implications for the potential role of probiotics and prebiotics in promoting human health. A group of experts recently met to review the latest advances in microbiota/microbiome research and discuss the implications for development of probiotics and prebiotics, primarily as they relate to effects mediated via the intestine. The goals of the meeting were to share recent advances in research on the microbiota, microbiome, probiotics, and prebiotics, and to discuss these findings in the contexts of regulatory barriers, evolving healthcare environments, and potential effects on a variety of health topics, including the development of obesity and diabetes; the long-term consequences of exposure to antibiotics early in life to the gastrointestinal (GI) microbiota; lactose intolerance; and the relationship between the GI microbiota and the central nervous system, with implications for depression, cognition, satiety, and mental health for people living in developed and developing countries. This report provides an overview of these discussions.
  36. Portal-Celhay, Cynthia; Nehrke, Keith; Blaser, Martin J. "Effect of Caenorhabditis elegans age and genotype on horizontal gene transfer in intestinal bacteria". FASEB journal. 2013 Feb;27(2):760-768 (MEDL:23085995 #227052)       

    Horizontal gene transfer (HGT) between bacteria occurs in the intestinal tract of their animal hosts and facilitates both virulence and antibiotic resistance. A model in which both the pathogen and the host are genetically tractable facilitates developing insight into mechanistic processes enabling or restricting the transfer of antibiotic resistance genes. Here we develop an in vivo experimental system to study HGT in bacteria using Caenorhabditis elegans as a model host. Using a thermosensitive conjugative system, we provide evidence that conjugation between two Escherichia coli strains can take place in the intestinal lumen of N2 wild-type worms at a rate of 10(-3) and 10(-2) per donor. We also show that C. elegans age and genotype are important determinants of the frequency of conjugation. Whereas approximately 1 transconjugant for every 100 donor cells could be recovered from the intestine of N2 C. elegans, for the age-1 and tol-1 mutants, the detected rate of transconjugation (10(-3) and 10(-4) per donor cell, respectively) was significantly lower. This work demonstrates that increased recombination among lumenal microbial populations is a phenotype associated with host aging, and the model provides a framework to study the dynamics of bacterial horizontal gene transfer within the intestinal environment.-Portal-Celhay, C., Nehrke, K., Blaser, M. J. Effect of Caenorhabditis elegans age and genotype on horizontal gene transfer in intestinal bacteria.
  37. Redel, Henry; Gao, Zhan; Li, Huilin; Alekseyenko, Alexander V; Zhou, Yanjiao; Perez-Perez, Guillermo I; Weinstock, George; Sodergren, Erica; Blaser, Martin J. "Quantitation and composition of cutaneous microbiota in diabetic and nondiabetic men". Journal of infectious diseases. 2013 Apr;207(7):1105-1114 (MEDL:23300163 #264262)       

    Background. Diabetic foot infections are a leading cause of lower extremity amputations. Our study examines the microbiota of diabetic skin prior to ulcer development or infection. Methods. In a case-control study, outpatient males were recruited at a veterans hospital. Subjects were swabbed at 4 cutaneous sites, 1 on the forearm and 3 on the foot. Quantitative polymerase chain reaction (qPCR) with primers and probes specific for bacteria, Staphylococcus species, Staphylococcus aureus, and fungi were performed on all samples. High-throughput 16S ribosomal RNA (rRNA) sequencing was performed on samples from the forearm and the plantar aspect of the foot. Results. qPCR analysis of swab specimens from 30 diabetic subjects and 30 control subjects showed no differences in total numbers of bacteria or fungi at any sampled site. Increased log concentrations of Staphylococcus aureus, quantified by the number of nuc gene copies, were present in diabetic men on the plantar aspect of the foot. High-throughput 16S rRNA sequencing found that, on the foot, the microbiota in controls (n = 24) was dominated by Staphylococcus species, whereas the microbiota in diabetics (n = 23) was more diverse at the genus level. The forearm microbiota had similar diversity in diabetic and control groups. Conclusions. The feet of diabetic men had decreased populations of Staphylococcus species, increased populations of S. aureus, and increased bacterial diversity, compared with the feet of controls. These ecologic changes may affect the risk for wound infections.
  38. Rhodes, Rosamond; Baumrin, Stefan Bernard; Blaser, Martin J; Earle, William J; Indyk, Debbie; Jabs, Ethylin Wang; Moros, Daniel A; Richardson, Lynne D; Sacks, Henry S. "Public health and research on populations" IN: The human microbiome : ethical, legal and social concerns. Oxford ; New York : Oxford University Press, 2013. . p.?-?.  (OCLC:840803662-04 #988682)    
  39. Segal, Leopoldo N; Alekseyenko, Alexander V; Clemente, Jose C; Kulkarni, Rohan; Wu, Benjamin; Chen, Hao; Berger, Kenneth I; Goldring, Roberta M; Rom, William N; Blaser, Martin J; Weiden, Michael D. "Enrichment of lung microbiome with supraglottic taxa is associated with increased pulmonary inflammation". Microbiome. 2013;1(1):19-19 (MEDL:24450871 #760012)       

    BACKGROUND: The lung microbiome of healthy individuals frequently harbors oral organisms. Despite evidence that microaspiration is commonly associated with smoking-related lung diseases, the effects of lung microbiome enrichment with upper airway taxa on inflammation has not been studied. We hypothesize that the presence of oral microorganisms in the lung microbiome is associated with enhanced pulmonary inflammation. To test this, we sampled bronchoalveolar lavage (BAL) from the lower airways of 29 asymptomatic subjects (nine never-smokers, 14 former-smokers, and six current-smokers). We quantified, amplified, and sequenced 16S rRNA genes from BAL samples by qPCR and 454 sequencing. Pulmonary inflammation was assessed by exhaled nitric oxide (eNO), BAL lymphocytes, and neutrophils. RESULTS: BAL had lower total 16S than supraglottic samples and higher than saline background. Bacterial communities in the lower airway clustered in two distinct groups that we designated as pneumotypes. The rRNA gene concentration and microbial community of the first pneumotype was similar to that of the saline background. The second pneumotype had higher rRNA gene concentration and higher relative abundance of supraglottic-characteristic taxa (SCT), such as Veillonella and Prevotella, and we called it pneumotypeSCT. Smoking had no effect on pneumotype allocation, alpha, or beta diversity. PneumotypeSCT was associated with higher BAL lymphocyte-count (P= 0.007), BAL neutrophil-count (P= 0.034), and eNO (P= 0.022). CONCLUSION: A pneumotype with high relative abundance of supraglottic-characteristic taxa is associated with enhanced subclinical lung inflammation.
  40. Statnikov, Alexander; Alekseyenko, Alexander V; Li, Zhiguo; Henaff, Mikael; Perez-Perez, Guillermo I; Blaser, Martin J; Aliferis, Constantin F. "Microbiomic signatures of psoriasis: feasibility and methodology comparison". Scientific reports. 2013 Sep;3:2620-2620 (MEDL:24018484 #529142)       

    Psoriasis is a common chronic inflammatory disease of the skin. We sought to use bacterial community abundance data to assess the feasibility of developing multivariate molecular signatures for differentiation of cutaneous psoriatic lesions, clinically unaffected contralateral skin from psoriatic patients, and similar cutaneous loci in matched healthy control subjects. Using 16S rRNA high-throughput DNA sequencing, we assayed the cutaneous microbiome for 51 such matched specimen triplets including subjects of both genders, different age groups, ethnicities and multiple body sites. None of the subjects had recently received relevant treatments or antibiotics. We found that molecular signatures for the diagnosis of psoriasis result in significant accuracy ranging from 0.75 to 0.89 AUC, depending on the classification task. We also found a significant effect of DNA sequencing and downstream analysis protocols on the accuracy of molecular signatures. Our results demonstrate that it is feasible to develop accurate molecular signatures for the diagnosis of psoriasis from microbiomic data.
  41. Statnikov, Alexander; Henaff, Mikael; Narendra, Varun; Konganti, Kranti; Li, Zhiguo; Yang, Liying; Pei, Zhiheng; Blaser, Martin J; Aliferis, Constantin F; Alekseyenko, Alexander V. "A comprehensive evaluation of multicategory classification methods for microbiomic data". Microbiome. 2013;1(1):11-11 (MEDL:24456583 #764032)       

    BACKGROUND: Recent advances in next-generation DNA sequencing enable rapid high-throughput quantitation of microbial community composition in human samples, opening up a new field of microbiomics. One of the promises of this field is linking abundances of microbial taxa to phenotypic and physiological states, which can inform development of new diagnostic, personalized medicine, and forensic modalities. Prior research has demonstrated the feasibility of applying machine learning methods to perform body site and subject classification with microbiomic data. However, it is currently unknown which classifiers perform best among the many available alternatives for classification with microbiomic data. RESULTS: In this work, we performed a systematic comparison of 18 major classification methods, 5 feature selection methods, and 2 accuracy metrics using 8 datasets spanning 1,802 human samples and various classification tasks: body site and subject classification and diagnosis. CONCLUSIONS: We found that random forests, support vector machines, kernel ridge regression, and Bayesian logistic regression with Laplace priors are the most effective machine learning techniques for performing accurate classification from these microbiomic data.
  42. Trasande, L; Blustein, J; Liu, M; Corwin, E; Cox, L M; Blaser, M J. "Infant antibiotic exposures and early-life body mass". International journal of obesity & related metabolic disorders. 2013 Jan;37(1):16-23 (MEDL:22907693 #211002)       

    Objectives:To examine the associations of antibiotic exposures during the first 2 years of life and the development of body mass over the first 7 years of life.Design:Longitudinal birth cohort study.Subjects:A total of 11 532 children born at >/=2500 g in the Avon Longitudinal Study of Parents and Children (ALSPAC), a population-based study of children born in Avon, UK in 1991-1992.Measurements:Exposures to antibiotics during three different early-life time windows (<6 months, 6-14 months, 15-23 months), and indices of body mass at five time points (6 weeks, 10 months, 20 months, 38 months and 7 years).Results:Antibiotic exposure during the earliest time window (<6 months) was consistently associated with increased body mass (+0.105 and +0.083 s.d. unit, increase in weight-for-length Z-scores at 10 and 20 months, P<0.001 and P=0.001, respectively; body mass index (BMI) Z-score at 38 months +0.067 s.d. units, P=0.009; overweight OR 1.22 at 38 months, P=0.029) in multivariable, mixed-effect models controlling for known social and behavioral obesity risk factors. Exposure from 6 to 14 months showed no association with body mass, while exposure from 15 to 23 months was significantly associated with increased BMI Z-score at 7 years (+0.049 s.d. units, P=0.050). Exposures to non-antibiotic medications were not associated with body mass.Conclusions:Exposure to antibiotics during the first 6 months of life is associated with consistent increases in body mass from 10 to 38 months. Exposures later in infancy (6-14 months, 15-23 months) are not consistently associated with increased body mass. Although effects of early exposures are modest at the individual level, they could have substantial consequences for population health. Given the prevalence of antibiotic exposures in infants, and in light of the growing concerns about childhood obesity, further studies are needed to isolate effects and define life-course implications for body mass and cardiovascular risks.
  43. Blaser, M; Bertagnoli, A; Raber, M; Nuss, K; Rasekh, M; Steiner, A. "Arthroscopic approaches to the fetlock joint of adult cattle: A cadaver study". Veterinary journal (London, England : 1997). 2012 Apr;:701-706 (MEDL:22513302 #165582)       

    The objective of the present study was to describe the arthroscopic anatomy of the bovine fetlock joint using one palmar/plantar and three dorsal joint approaches. A comparative anatomic, ultrasonographic and arthroscopic study using 20 cadaveric feet from 13 non-lame adult dairy cows was performed. Arthroscopy was accomplished using a rigid arthroscope to view the synovial cavities with their synovial villi and parts of the following structures: the distal ends of the metacarpal/metatarsal III/IV bones with their trochleae and sagittal ridges, synovial grooves, the articular surfaces of the proximal sesamoid bones, the proximal aspects of the first phalanges, the lateral and medial collateral ligaments, the suspensory ligament and the interdigital ligaments as parts of the interosseus muscle, the cruciate sesamoidean ligaments, the communication site between the lateral and medial pouch in the palmar/plantar area, and dorsally the septum between the lateral and the medial pouch. The technique allowed a good overall view of most relevant structures in the sound cadaver joint. Further investigations are warranted to evaluate the diagnostic, therapeutic and prognostic applications of these techniques in the treatment of septic arthritis.
  44. Blaser, Martin J. "Equilibria of humans and our indigenous microbiota affecting asthma". Proceedings of the American Thoracic Society. 2012 May;9(2):69-71 (MEDL:22550247 #166523)       

    It is becoming increasingly clear that our residential microbes, the key constituents in the human microbiome, are centrally involved in many aspects of our physiology. In particular, the ancient and dominant gastric bacteria Helicobacter pylori are highly interactive with human physiology. In modern times, H. pylori has been disappearing, which consequently affects the interactions between luminal bacteria and epithelial, lymphoid, and neuroendocrine cells. A growing body of evidence indicates that H. pylori protects against childhood-onset asthma, probably through the gastric recruitment of regulatory T cells. The phenomenon of disappearing ancient microbiota may be a general paradigm driving the diseases of modernity.
  45. Blaser, Martin J. "Heterogeneity of Helicobacter pylori". European journal of gastroenterology & hepatology. 2012 Apr;9 Suppl 1:S3-6; discussion S6 (MEDL:22498905 #165579)    

    : Although many physicians view Helicobacter pylori strains as a homogenous groupof organisms, it has become increasingly clear that populations in humans are highly diverse. This heterogeneity can be analyzed at two different levels: genotypic variation among strains and variations in H. pylori populations within an individual host. Genotypic variation includes point mutations in conserved genes (e.g. ureC), variation in the gene order on physical maps, mosaicism in conserved genes (e.g. vacAs1a), non-conserved genes (e.g. cagA) and extragenetic elements (e.g. IS605). Population differences include the observations that humans can be simultaneously infected with two or more H. pylori strains and that a single strain may represent a cluster of closely related organisms (a 'quasispecies'). The presence of multiple organisms within a host may occur as a result of recombination events leading to genetic shift, whereas ongoing mutation within a strain can lead to the formation of quasispecies by genetic drift. Over recent years it has become increasingly clear that observations on the fundamental biology of H. pylori have considerable clinical relevance. Several genotypic markers (e.g. cagA, vacA, s1a and iceA1) are associated with an increased risk of disease. Also, the multiplicity of infection and quasispecies indicates that analysis of a single H. pylori isolate is inaccurate for defining the genotype of H. pylori strains present in a patient. Global assays, such as serology, are more suitable. The aim of this paper is to review the general phenomenon of diversity in H. pylori and to describe particular heterogeneities that are related to clinical outcome.
  46. Blaser, Martin J. "The Jeremiah Metzger lecture: Global warming redux: the disappearing microbiota and epidemic obesity [Lecture]". Transactions of the American Clinical & Climatological Association. 2012;123:230-8; discussion 239 (MEDL:23303990 #223182)    
  47. Chen, Yu; Blaser, Martin J. "Association Between Gastric Helicobacter pylori Colonization and Glycated Hemoglobin Levels". Journal of infectious diseases. 2012 Apr;205(8):1195-1202 (MEDL:22427676 #164397)       

    (See the editorial commentary by Cohen and Muhsen, on pages 1183-5.) Background. Few studies have evaluated the potential influence of Helicobacter pylori on biomarkers for diabetes. Methods. We conducted cross-sectional analyses using data from 7417 participants in the National Health and Nutrition Examination Survey (NHANES) III (aged >/=18 years) and 6072 participants in NHANES 1999-2000 (aged >/=3 years) to assess the association between H. pylori and levels of glycosylated hemoglobin (HbA1c). Results. There was no association between H. pylori and history of self-reported diabetes. Helicobacter pylori seropositivity, especially H. pylori cagA positivity, was positively associated (P < .01, NHANES III; P = .02, NHANES 1999-2000) with HbA1c levels after excluding individuals with history of diabetes and controlling for potential confounders. There was also a synergistic interaction between H. pylori and higher body mass index (BMI), such that increased levels of HbA1c associated with having both H. pylori and higher BMI were greater than the sum of their individual effects (P for interaction < .01). This interaction was observed consistently in both NHANES III and NHANES 1999-2000 and for H. pylori cagA positivity in NHANES III. Conclusions. The findings indicate a role of H. pylori in impaired glucose tolerance in adults that may be potentiated by higher BMI level.
  48. Cho, Ilseung; Blaser, Martin J. "The human microbiome: at the interface of health and disease". Nature reviews. Genetics. 2012;13(4):260-270 (MEDL:22411464 #162035)       

    Interest in the role of the microbiome in human health has burgeoned over the past decade with the advent of new technologies for interrogating complex microbial communities. The large-scale dynamics of the microbiome can be described by many of the tools and observations used in the study of population ecology. Deciphering the metagenome and its aggregate genetic information can also be used to understand the functional properties of the microbial community. Both the microbiome and metagenome probably have important functions in health and disease; their exploration is a frontier in human genetics.
  49. Cho, Ilseung; Yamanishi, Shingo; Cox, Laura; Methe, Barbara A; Zavadil, Jiri; Li, Kelvin; Gao, Zhan; Mahana, Douglas; Raju, Kartik; Teitler, Isabel; Li, Huilin; Alekseyenko, Alexander V; Blaser, Martin J. "Antibiotics in early life alter the murine colonic microbiome and adiposity". Nature. 2012 Aug;488(7413):621-626 (MEDL:22914093 #177150)       

    Antibiotics administered in low doses have been widely used as growth promoters in the agricultural industry since the 1950s, yet the mechanisms for this effect are unclear. Because antimicrobial agents of different classes and varying activity are effective across several vertebrate species, we proposed that such subtherapeutic administration alters the population structure of the gut microbiome as well as its metabolic capabilities. We generated a model of adiposity by giving subtherapeutic antibiotic therapy to young mice and evaluated changes in the composition and capabilities of the gut microbiome. Administration of subtherapeutic antibiotic therapy increased adiposity in young mice and increased hormone levels related to metabolism. We observed substantial taxonomic changes in the microbiome, changes in copies of key genes involved in the metabolism of carbohydrates to short-chain fatty acids, increases in colonic short-chain fatty acid levels, and alterations in the regulation of hepatic metabolism of lipids and cholesterol. In this model, we demonstrate the alteration of early-life murine metabolic homeostasis through antibiotic manipulation.
  50. Gupta, Vinay; Perez-Perez, Guillermo I; Dorsey, Grant; Rosenthal, Philip J; Blaser, Martin J. "Reply to comment on: The seroprevalence of Helicobacter pylori and its relationship to malaria in Ugandan children [Letter]". Transactions of the Royal Society of Tropical Medicine & Hygiene. 2012 May;106:330-330 (MEDL:22480790 #165583)       
  51. Gupta, Vinay; Perez-Perez, Guillermo I; Dorsey, Grant; Rosenthal, Philip J; Blaser, Martin J. "The seroprevalence of Helicobacter pylori and its relationship to malaria in Ugandan children". Transactions of the Royal Society of Tropical Medicine & Hygiene. 2012 Jan;106(1):35-42 (MEDL:22018600 #165586)       

    Helicobacter pylori epidemiology in sub-Saharan Africa, particularly among children, has been little investigated. A secondary endpoint of our study was to examine for associations between the seroprevalence of H. pylori and the incidence of malaria. We explored H. pylori prevalence by measuring serum IgG antibodies to H. pylori whole cell and cytotoxin-associated gene A (CagA) antigens by ELISA in a longitudinal cohort of 200 Ugandan children, aged 1-10 years at enrollment, in whom malaria incidence was followed over 572 person-years. First-sample seroprevalence for H. pylori -specific IgG (63%) and for the H. pylori protein CagA (78.5%) were both high, and they were positively associated with advancing age (per each 1-year age increase, OR (95% CI): 1.60 (1.39-1.85), P<0.001). We observed nearly universal prevalence of CagA+ H. pylori by the age of 10 years in Kampala and found no evidence that H. pylori-positivity is protective against malaria.
  52. Holster, I Lisanne; Vila, Anne Marie J; Caudri, Daan; den Hoed, Caroline M; Perez-Perez, Guillermo I; Blaser, Martin J; de Jongste, Johan C; Kuipers, Ernst J. "The Impact of Helicobacter pylori on Atopic Disorders in Childhood". Helicobacter. 2012 Jun;17(3):232-237 (MEDL:22515362 #165581)       

    Background: The prevalence of Helicobacter pylori in Western populations has steadily decreased. This has been suggested as one of the factors involved in the recent increase of asthma and allergy. Some studies have reported a negative association between H. pylori and asthma and allergy, but data are inconsistent and there are a few studies in children. Aim: We investigated whether the prevalence of H. pylori was associated with asthma symptoms, allergic rhinitis, and atopic dermatitis in childhood. Methods: We determined IgG anti-H. pylori and CagA antibodies in serum of Dutch children, who took part in the PIAMA birth cohort study. Serum was collected from 545 children, aged 7-9 years (Dutch ethnicity 91.5%). Symptoms of asthma and atopy were assessed by yearly questionnaires. Chi-square tests and logistic regression were used. Results: We found 9%H. pylori and 0.9% CagA seropositivity. Twelve (5.9%) children with reported wheezing ever were H. pylori positive, compared to 37 (10.9%) of the non-wheezers (p = .05). No significant differences in H. pylori prevalence were found between children with or without allergic rhinitis (8.5% vs 9.5%), atopic dermatitis (8.7% vs 9.2%), and physician-diagnosed asthma (7.1% vs 9.4%). Multivariate analysis showed no significant associations between H. pylori seropositivity and wheezing (OR 0.52; 95% CI 0.25-1.06), allergic rhinitis (OR 0.96; 95% CI 0.51-1.81), atopic dermatitis (OR 1.05; 95% CI 0.56-1.98) or physician-diagnosed asthma (OR 0.87; 95% CI 0.37-2.08). Conclusion: We found a borderline significantly lower H. pylori seropositivity in children with wheezing compared to non-wheezers, but no association between H. pylori serum-antibody status and allergic rhinitis, atopic dermatitis, or asthma.
  53. Kienesberger, Sabine; Perez-Perez, Guillermo I; Rivera-Correa, Juan L; Tosado-Acevedo, Rafael; Li, Huilin; Dubois, Andre; Gonzalez-Martinez, Janis A; Dominguez Bello, Maria Gloria; Blaser, Martin J. "Serologic host response to Helicobacter pylori and Campylobacter jejuni in socially housed Rhesus macaques (Macaca mulatta)". Gut pathogens. 2012 Aug;4(1):9-9 (MEDL:22920270 #175980)       

    ABSTRACT: BACKGROUND: Helicobacter pylori are successful colonizers of the human gastric mucosa. Colonization increases the risk of peptic ulcer disease and adenocarcinoma. However, potential benefits of H. pylori colonization include protection against early-onset asthma and against gastrointestinal infections. Campylobacter jejuni are a leading cause of bacterial diarrhea and complications include Guillain-Barre syndrome. Here, we describe the development of reliable serological assays to detect antibodies against those two bacteria in Rhesus macaques and investigated their distribution within a social group of monkeys. METHODS: Two cohorts of monkeys were analyzed. The first cohort consisted of 30 monkeys and was used to establish an enzyme-linked immunosorbent assay (ELISA) for H. pylori antibodies detection. To evaluate colonization of those macaques, stomach biopsies were collected and analyzed for the presence of H. pylori by histology and culture. C. jejuni ELISAs were established using human serum with known C. jejuni antibody status. Next, plasma samples of the 89 macaques (cohort 2) were assayed for antibodies and then statistically analyzed. RESULTS: An H. pylori IgG ELISA, which was 100% specific and 93% sensitive, was established. In contrast, the IgA ELISA was only 82% specific and 61% sensitive. The CagA IgG assay was 100% sensitive and 61% of the macaques were positive. In cohort 2, 62% macaques were H. pylori sero-positive and 52% were CagA positive. The prevalence of H. pylori IgG and CagA IgG increased with monkey age as described for humans. Of the 89 macaques 52% showed IgG against C. jejuni but in contrast to H. pylori, the sero-prevalence was not associated with increasing age. However, there was a drop in the IgG (but not in IgA) mean values between infant and juvenile macaques, similar to trends described in humans. CONCLUSIONS: Rhesus macaques have widespread exposure to H. pylori and C. jejuni, reflecting their social conditions and implying that Rhesus macaques might provide a model to study effects of these two important human mucosal bacteria on a population.
  54. Koshiol, Jill; Flores, Roberto; Lam, Tram K; Taylor, Philip R; Weinstein, Stephanie J; Virtamo, Jarmo; Albanes, Demetrius; Perez-Perez, Guillermo; Caporaso, Neil E; Blaser, Martin J. "Helicobacter pylori seropositivity and risk of lung cancer". PLoS ONE. 2012;7(2):e32106-e32106 (e32106) (MEDL:22384154 #165585)       

    Lung cancer is the leading cause of cancer mortality worldwide. Helicobacter pylori (H. pylori) is a risk factor for distal stomach cancer, and a few small studies have suggested that H. pylori may be a potential risk factor for lung cancer. To test this hypothesis, we conducted a study of 350 lung adenocarcinoma cases, 350 squamous cell carcinoma cases, and 700 controls nested within the Alpha-Tocopherol, Beta-Carotene Cancer Prevention Study (ATBC) cohort of male Finnish smokers. Controls were one-to-one matched by age and date of baseline serum draw. Using enzyme-linked immunosorbent assays to detect immunoglobulin G antibodies against H. pylori whole-cell and cytotoxin-associated gene (CagA) antigens, we calculated odds ratios (ORs) and 95% confidence intervals (95% CIs) for associations between H. pylori seropositivity and lung cancer risk using conditional logistic regression. H. pylori seropositivity was detected in 79.7% of cases and 78.5% of controls. After adjusting for pack-years and cigarettes smoked per day, H. pylori seropositivity was not associated with either adenocarcinoma (OR: 1.1, 95% CI: 0.75-1.6) or squamous cell carcinoma (OR: 1.1, 95% CI: 0.77-1.7). Results were similar for CagA-negative and CagA-positive H. pylori seropositivity. Despite earlier small studies suggesting that H. pylori may contribute to lung carcinogenesis, H. pylori seropositivity does not appear to be associated with lung cancer.
  55. Pohl, Mary Ann; Kienesberger, Sabine; Blaser, Martin J. "Novel Functions for Glycosyltransferases Jhp0562 and GalT in Lewis Antigen Synthesis and Variation in Helicobacter pylori". Infection & immunity. 2012 Apr;80(4):1593-1605 (MEDL:22290141 #164406)       

    Lewis (Le) antigens are fucosylated oligosaccharides present in the Helicobacter pylori lipopolysaccharide. Expression of these antigens is believed to be important for H. pylori colonization, since Le antigens also are expressed on the gastric epithelia in humans. A galactosyltransferase encoded by beta-(1,3)galT is essential for production of type 1 (Le(a) and Le(b)) antigens. The upstream gene jhp0562, which is present in many but not all H. pylori strains, is homologous to beta-(1,3)galT but is of unknown function. Because H. pylori demonstrates extensive intragenomic recombination, we hypothesized that these two genes could undergo DNA rearrangement. A PCR screen and subsequent sequence analyses revealed that the two genes can recombine at both the 5' and 3' ends. Chimeric beta-(1,3)galT-like alleles can restore function in a beta-(1,3)galT null mutant, but neither native nor recombinant jhp0562 can. Mutagenesis of jhp0562 revealed that it is essential for synthesis of both type 1 and type 2 Le antigens. Transcriptional analyses of both loci showed beta-(1,3)galT expression in all wild-type (WT) and mutant strains tested, whereas jhp0562 was not expressed in jhp0562 null mutants, as expected. Since jhp0562 unexpectedly displayed functions in both type 1 and type 2 Le synthesis, we asked whether galT, part of the type 2 synthesis pathway, had analogous functions in type 1 synthesis. Mutagenesis and complementation analysis confirmed that galT is essential for Le(b) production. In total, these results demonstrate that galT and jhp0562 have functions that cross the expected Le synthesis pathways and that jhp0562 provides a substrate for intragenomic recombination to generate diverse Le synthesis enzymes.
  56. Portal-Celhay, C; Bradley, ER; Blaser, MJ. "Control of intestinal bacterial proliferation in regulation of lifespan in Caenorhabditis elegans". BMC microbiology. 2012 Mar;12(1):49-49 (MEDL:22452899 #165584)       

    ABSTRACT: BACKGROUND: A powerful approach to understanding complex processes such as aging is to use model organisms amenable to genetic manipulation, and to seek relevant phenotypes to measure. Caenorhabditis elegans is particularly suited to studies of aging, since numerous single-gene mutations have been identified that affect its lifespan; it possesses an innate immune system employing evolutionarily conserved signaling pathways affecting longevity. As worms age, bacteria accumulate in the intestinal tract. However, quantitative relationships between worm genotype, lifespan, and intestinal lumen bacterial load have not been examined. We hypothesized that gut immunity is less efficient in older animals, leading to enhanced bacterial accumulation, reducing longevity. To address this question, we evaluated the ability of worms to control bacterial accumulation as a functional marker of intestinal immunity. RESULTS: We show that as adult worms age, several C. elegans genotypes show diminished capacity to control intestinal bacterial accumulation. We provide evidence that intestinal bacterial load, regulated by gut immunity, is an important causative factor of lifespan determination; the effects are specified by bacterial strain, worm genotype, and biologic age, all acting in concert. CONCLUSIONS: In total, these studies focus attention on the worm intestine as a locus that influences longevity in the presence of an accumulating bacterial population. Further studies defining the interplay between bacterial species and host immunity in C. elegans may provide insights into the general mechanisms of aging and age-related diseases.
  57. Portal-Celhay, Cynthia; Blaser, Martin J. "Competition and Resilience between Founder and Introduced Bacteria in the Caenorhabditis elegans Gut". Infection & immunity. 2012 Mar;80(3):1288-1299 (MEDL:22184417 #160245)       

    The microbial communities that reside within the intestinal tract in vertebrates are complex and dynamic. In this report, we establish the utility of Caenorhabditis elegans as a model system for identifying the factors that contribute to bacterial persistence and for host control of gut luminal populations. We found that for N2 worms grown on mixed lawns of bacteria, Salmonella enterica serovar Typhimurium substantially outcompeted Escherichia coli, even when E. coli was initially present at 100-fold-higher concentrations. To address whether innate immunity affects the competition, the daf-2 and daf-16 mutants were studied; their total gut bacterial levels reflect overall capacity for colonization, but Salmonella outcompeted E. coli to an extent similar to wild-type worms. To address the role of virulence properties, Salmonella Deltaspi-1 Deltaspi-2 was used to compete with E. coli. The net differential was significantly less than that for wild-type Salmonella; thus, spi-1 spi-2 encodes C. elegans colonization factors. An E. coli strain with repeated in vivo passage had an enhanced ability to compete against an in vitro-passed E. coli strain and against Salmonella. Our data provide evidence of active competition for colonization niches in the C. elegans gut, as determined by bacterial factors and subject to in vivo selection.
  58. Salazar, Christian R; Francois, Fritz; Li, Yihong; Corby, Patricia; Hays, Rosemary; Leung, Celine; Bedi, Sukhleen; Segers, Stephanie; Queiroz, Erica; Sun, Jinghua; Wang, Beverly; Ho, Hao; Craig, Ronald; Cruz, Gustavo D; Blaser, Martin J; Perez-Perez, Guillermo; Hayes, Richard B; Dasanayake, Ananda; Pei, Zhiheng; Chen, Yu. "Association between oral health and gastric precancerous lesions". Carcinogenesis. 2012 Feb;33(2):399-403 (MEDL:22139442 #156487)       

    Although recent studies have suggested that tooth loss is positively related to the risk of gastric non-cardia cancer, the underlying oral health conditions potentially responsible for the association remain unknown. We investigated whether clinical and behavioral measures of oral health are associated with the risk of gastric precancerous lesions. We conducted a cross-sectional study of 131 patients undergoing upper gastrointestinal endoscopy. Cases were defined as those with gastric precancerous lesions including intestinal metaplasia or chronic atrophic gastritis on the basis of standard biopsy review. A validated structured questionnaire was administered to obtain information on oral health behaviors. A comprehensive clinical oral health examination was performed on a subset of 91 patients to evaluate for periodontal disease and dental caries experience. A total of 41 (31%) cases of gastric precancerous lesions were identified. Compared with non-cases, cases were significantly more likely to not floss their teeth [odds ratio (OR) = 2.89, 95% confidence interval (CI): 1.09-7.64], adjusting for age, sex, race, body mass index, smoking status, educational attainment and Helicobacter pylori status in serum. Among participants who completed the oral examination, cases (n = 28) were more likely to have a higher percentage of sites with gingival bleeding than non-cases [OR = 2.63, 95% CI: 1.37-5.05 for a standard deviation increase in bleeding sites (equivalent to 19.7%)], independent of potential confounders. Our findings demonstrate that specific oral health conditions and behaviors such as gingival bleeding and tooth flossing are associated with gastric precancerous lesions.
  59. Zhang, XS; Blaser, MJ. "Natural transformation of an engineered Helicobacter pylori strain deficient in type II restriction endonucleases". Journal of bacteriology. 2012 Apr;:3407-3416 (MEDL:22522893 #165580)       

    Restriction-modification (RM) systems are important for bacteria to limit foreign DNA invasion. The naturally competent bacterium Helicobacter pylori has highly diverse strain-specific type II systems. To evaluate the roles of strain-specific restriction in H. pylori natural transformation, a markerless type II restriction endonuclease-deficient (REd) mutant was constructed. We deleted the genes encoding all four active type II restriction endonucleases in H. pylori strain 26695 using sacB-mediated counter-selection. Transformation by donor DNA with exogenous cassettes methylated by E. coli was substantially (1.7 log(10) and 2.0 log(10), for cat and aphA, respectively) increased in the REd strain. There also was significantly increased transformation of the REd strain by donor DNA from other H. pylori strains, to an extent corresponding to their shared type II R-M system strain-specificity with 26695. Comparison of the REd and wild type strains indicates that restriction did not affect the length of DNA fragment integration during natural transformation. There also were no differentials in cell growth or susceptibility to DNA damage. In total, the data indicate that the type II REd mutant has enhanced competence with no loss of growth or repair facility compared to the wild type, facilitating H. pylori mutant construction and other genetic engineering.
  60. Zhang, Xue-Song; Blaser, Martin J. "DprB Facilitates Inter- and Intragenomic Recombination in Helicobacter pylori". Journal of bacteriology. 2012 Aug;194(15):3891-3903 (MEDL:22609923 #174069)       

    For naturally competent microorganisms, such as Helicobacter pylori, the steps that permit recombination of exogenous DNA are not fully understood. Immediately downstream of an H. pylori gene (dprA) that facilitates high-frequency natural transformation is HP0334 (dprB), annotated to be a putative Holliday junction resolvase (HJR). We showed that the HP0334 (dprB) gene product facilitates high-frequency natural transformation. We determined the physiologic roles of DprB by genetic analyses. DprB controls in vitro growth, survival after exposure to UV or fluoroquinolones, and intragenomic recombination. dprB ruvC double deletion dramatically decreases both homologous and homeologous transformation and survival after exposure to DNA-damaging agents. Moreover, the DprB protein binds to synthetic Holliday junction structures rather than double-stranded or single-stranded DNA. These results demonstrate that the dprB product plays important roles affecting inter- and intragenomic recombination. We provide evidence that the two putative H. pylori HJRs (DprB and RuvC) have overlapping but distinct functions involving intergenomic (primarily DprB) and intragenomic (primarily RuvC) recombination.
  61. Blaser, Martin. "Antibiotic overuse: Stop the killing of beneficial bacteria". Nature. 2011 Aug 25;476(7361):393-394 (MEDL:21866137 #136953)       
  62. Blaser, Martin J. "Deconstructing a lethal foodborne epidemic [Editorial]". New England journal of medicine. 2011 Nov 10;365(19):1835-1836 (MEDL:22029755 #146224)       
  63. Blaser, Martin J. "Detecting a bacterial protein to understand cancer risk". Clinical chemistry. 2011 Sep;57(9):1331-1332 (MEDL:21586641 #138105)       
  64. Chen, Yu; Blaser, Martin J. "Farm microbiome and childhood asthma [Letter]". New England journal of medicine. 2011 May 19;364(20):1972-3; author reply 1973 (MEDL:21591951 #140485)       
  65. den Hoed, Caroline M; Vila, Anne J; Holster, Ingrid L; Perez-Perez, Guillermo I; Blaser, Martin J; de Jongste, Johan C; Kuipers, Ernest J. "Helicobacter pylori and the birth cohort effect: evidence for stabilized colonization rates in childhood". Helicobacter. 2011 Oct;16(5):405-409 (MEDL:21923687 #137846)       

    Background: The prevalence of Helicobacter pylori has declined over recent decades in developed countries. The increasing prevalence with age is largely because of a birth cohort effect. We previously observed a decline in H. pylori prevalence in 6- to 8-year-old Dutch children from 19% in 1978 to 9% in 1993. Knowledge about birth-cohort-related H. pylori prevalence is relevant as a predictor for the future incidence of H. pylori-associated conditions. Aim: The aim of this study was to investigate whether the birth cohort effect of H. pylori observed between 1978 and 1993 continued in subsequent years. Methods: Anti-H. pylori IgG antibodies and anti-CagA IgG antibodies were determined in serum samples obtained in 2005/2006 from 545 Dutch children aged 7-9 years who participated in the Prevention and Incidence of Asthma and Mite Allergy birth cohort. The H. pylori and CagA antibodies were determined by enzyme-linked immunosorbent assays that have been extensively validated in children, with a 94% sensitivity for H. pylori colonization and a 92.5% sensitivity for colonization with a cagA-positive strain. Results: Of the 545 children (M/F 300/245), most (91.5%) were of Dutch descent. The H. pylori positivity rate was 9% (95% CI 6.6-11.4%). The prevalence of CagA antibodies was 0.9% (95% CI 0.1-1.6%). No significant differences were demonstrated in H. pylori and cagA prevalence in relation to gender or ethnicity. Conclusion: The prevalence of H. pylori in childhood has remained stable in the Netherlands from 1993 to 2005, suggesting a stabilization of the previously decreasing trend in subsequent birth cohorts. This finding may reflect stabilization in determinants such as family size, housing, and hygienic conditions (or offset by day care). If confirmed in other populations in developed countries, it implies that colonization with H. pylori will remain common in the coming decades. Remarkably however, the rate of colonization with cagA(+) H. pylori strains has become very low, consistent with prior observations that cagA(+) strains are disappearing in Western countries
  66. Dominguez-Bello, Maria Gloria; Blaser, Martin J.. "The Human Microbiota as a Marker for Migrations of Individuals and Populations". Annual review of anthropology. 2011;40:451-474 (ISI:000299376200029 #161202)       
  67. Dominguez-Bello, Maria Gloria; Blaser, Martin J; Ley, Ruth E; Knight, Rob. "Development of the human gastrointestinal microbiota and insights from high-throughput sequencing". Gastroenterology. 2011 May;140(6):1713-1719 (MEDL:21530737 #133417)       

    Little was known about the development of the gastrointestinal (GI) tract microbiota, until recently, because of difficulties in obtaining sufficient sequence information from enough people or time points. Now, with decreased costs of DNA sequencing and improved bioinformatic tools, we can compare GI tract bacterial communities among individuals, of all ages from infancy to adulthood. Some key recent findings are that the initial bacterial community, even in the GI tract, depends strongly on delivery mode; that the process of early development of the microbiota is highly unstable and idiosyncratic; that the microbiota differs considerably among children from different countries; and that older adults have substantially different GI tract communities than younger adults, indicating that the GI tract microbiota can change throughout life. We relate these observations to different models of evolution including the evolution of senescence and suggest that probiotics be selected based on patient age. Studies of the microbiota in older people might tell us which probiotics could increase longevity. Drug metabolism varies among individuals with different microbial communities, so age- and region-specific clinical trials are required to ensure safety and efficacy
  68. Francois, Fritz; Roper, Jatin; Joseph, Neal; Pei, Zhiheng; Chhada, Aditi; Shak, Joshua R; de Perez, Asalia Z Olivares; Perez-Perez, Guillermo I; Blaser, Martin J. "The effect of H. pylori eradication on meal-associated changes in plasma ghrelin and leptin". BMC gastroenterology. 2011;11:37-37 (MEDL:21489301 #132313)       

    ABSTRACT: BACKGROUND: Appetite and energy expenditure are regulated in part by ghrelin and leptin produced in the gastric mucosa, which may be modified by H. pylori colonization. We prospectively evaluated the effect of H. pylori eradication on meal-associated changes in serum ghrelin and leptin levels, and body weight. METHODS: Veterans referred for upper GI endoscopy were evaluated at baseline and >/=8 weeks after endoscopy, and H. pylori status and body weight were ascertained. During the first visit in all subjects, and during subsequent visits in the initially H. pylori-positive subjects and controls, blood was collected after an overnight fast and 1 h after a standard high protein meal, and levels of eight hormones determined. RESULTS: Of 92 enrolled subjects, 38 were H. pylori-negative, 44 H. pylori-positive, and 10 were indeterminate. Among 23 H. pylori-positive subjects who completed evaluation after treatment, 21 were eradicated, and 2 failed eradication. After a median of seven months following eradication, six hormones related to energy homeostasis showed no significant differences, but post-prandial acylated ghrelin levels were nearly six-fold higher than pre-eradication (p = 0.005), and median integrated leptin levels also increased (20%) significantly (p < 0.001). BMI significantly increased (5 +/- 2%; p = 0.008) over 18 months in the initially H. pylori-positive individuals, but was not significantly changed in those who were H. pylori-negative or indeterminant at baseline. CONCLUSIONS: Circulating meal-associated leptin and ghrelin levels and BMI changed significantly after H. pylori eradication, providing direct evidence that H. pylori colonization is involved in ghrelin and leptin regulation, with consequent effects on body morphometry
  69. Goldman, Cinthia G; Matteo, Mario J; Loureiro, Julio D; Almuzara, Marisa; Barberis, Claudia; Vay, Carlos; Catalano, Mariana; Heredia, Sergio Rodriguez; Mantero, Paula; Boccio, Jose R; Zubillaga, Marcela B; Cremaschi, Graciela A; Solnick, Jay V; Perez-Perez, Guillermo I; Blaser, Martin J. "Novel gastric helicobacters and oral campylobacters are present in captive and wild cetaceans". Veterinary microbiology. 2011 Aug 26;152(1-2):138-145 (MEDL:21592686 #136497)       

    The mammalian gastric and oral mucosa may be colonized by mixed Helicobacter and Campylobacter species, respectively, in individual animals. To better characterize the presence and distribution of Helicobacter and Campylobacter among marine mammals, we used PCR and 16S rDNA sequence analysis to examine gastric and oral samples from ten dolphins (Tursiops gephyreus), one killer whale (Orcinus orca), one false killer whale (Pseudorca crassidens), and three wild La Plata river dolphins (Pontoporia blainvillei). Helicobacter spp. DNA was widely distributed in gastric and oral samples from both captive and wild cetaceans. Phylogenetic analysis demonstrated two Helicobacter sequence clusters, one closely related to H. cetorum, a species isolated from dolphins and whales in North America. The second related cluster was to sequences obtained from dolphins in Australia and to gastric non-H. pylori helicobacters, and may represent a novel taxonomic group. Dental plaque sequences from four dolphins formed a third cluster within the Campylobacter genus that likely represents a novel species isolated from marine mammals. Identification of identical Helicobacter spp. DNA sequences from dental plaque, saliva and gastric fluids from the same hosts, suggests that the oral cavity may be involved in transmission. These results demonstrate that Helicobacter and Campylobacter species are commonly distributed in marine mammals, and identify taxonomic clusters that may represent novel species
  70. Jones, Marcus B.; Peterson, Scott N.; Benn, Rosslyn; Braisted, John C.; Jarrahi, Behnam; Shatzkes, Kenneth; Ren, Dacheng; Wood, Thomas K.; Blaser, Martin J.. "Role of luxS in Bacillus anthracis growth and virulence factor expression (vol 1, pg 72, 2010)". Virulence. 2011 MAR-APR;2(2):172-172 (ISI:0002925235000 #135630)    
  71. Keo, Thormika; Collins, Jennifer; Kunwar, Pratima; Blaser, Martin J; Iovine, Nicole M. "Campylobacter capsule and lipooligosaccharide confer resistance to serum and cationic antimicrobials". Virulence. 2011 Jan 1;2(1):30-40 (MEDL:21266840 #123208)       

    The innate immune system plays a critical role in host defense against mucosal bacteria. Campylobacter jejuni is a major cause of human gastroenteritis that usually resolves spontaneously within several days, suggesting that innate mechanisms are important to control the infection. However, the specific means by which this occurs is not well understood. While diarrheal isolates of C. jejuni usually are susceptible to human serum, we found that a systemic strain of C. jejuni, isolated from the cerebrospinal fluid of an infant with meningitis, is relatively more resistant to human serum, the Bactericidal/Permeability-Increasing Protein (BPI), an endogenous cationic antimicrobial protein, and the cationic peptide antibiotic polymyxin B. To test the hypothesis that the surface properties of this strain contributed to its ability to withstand these innate host defenses, we constructed isogenic mutants in capsule (kpsM) and lipooligosaccharide (waaF) and complemented these mutants by insertion of the complementation construct in trans into hipO, a chromosomal locus. We found that capsule expression was essential for serum resistance, whereas lipooligosaccharide played no substantial role. In contrast, the lipooligosaccharide mutant showed increased sensitivity to polymyxin B, alpha-defensins, cathelicidins, and BPI. These findings suggest that the polysaccharides of C. jejuni strains contribute differently to resistance against host innate immunity; whereby capsule is more important for resisting human complement and lipooligosaccharide is more important for protection against killing mediated by cationic antimicrobial peptides and proteins
  72. Maldonado-Contreras, Ana; Goldfarb, Kate C; Godoy-Vitorino, Filipa; Karaoz, Ulas; Contreras, Monica; Blaser, Martin J; Brodie, Eoin L; Dominguez-Bello, Maria G. "Structure of the human gastric bacterial community in relation to Helicobacter pylori status". ISME journal. 2011 Apr;5(4):574-579 (MEDL:20927139 #134261)       

    The human stomach is naturally colonized by Helicobacter pylori, which, when present, dominates the gastric bacterial community. In this study, we aimed to characterize the structure of the bacterial community in the stomach of patients of differing H. pylori status. We used a high-density 16S rRNA gene microarray (PhyloChip, Affymetrix, Inc.) to hybridize 16S rRNA gene amplicons from gastric biopsy DNA of 10 rural Amerindian patients from Amazonas, Venezuela, and of two immigrants to the United States (from South Asia and Africa, respectively). H. pylori status was determined by PCR amplification of H. pylori glmM from gastric biopsy samples. Of the 12 patients, 8 (6 of the 10 Amerindians and the 2 non-Amerindians) were H. pylori glmM positive. Regardless of H. pylori status, the PhyloChip detected Helicobacteriaceae DNA in all patients, although with lower relative abundance in patients who were glmM negative. The G2-chip taxonomy analysis of PhyloChip data indicated the presence of 44 bacterial phyla (of which 16 are unclassified by the Taxonomic Outline of the Bacteria and Archaea taxonomy) in a highly uneven community dominated by only four phyla: Proteobacteria, Firmicutes, Actinobacteria and Bacteroidetes. Positive H. pylori status was associated with increased relative abundance of non-Helicobacter bacteria from the Proteobacteria, Spirochetes and Acidobacteria, and with decreased abundance of Actinobacteria, Bacteroidetes and Firmicutes. The PhyloChip detected richness of low abundance phyla, and showed marked differences in the structure of the gastric bacterial community according to H. pylori status
  73. Martins, Berta M; Blaser, Martin; Feliks, Mikolaj; Ullmann, G Matthias; Buckel, Wolfgang; Selmer, Thorsten. "Structural basis for a Kolbe-type decarboxylation catalyzed by a glycyl radical enzyme". Journal of the American Chemical Society. 2011 Sep;133(37):14666-14674 (MEDL:21823587 #165587)       

    4-Hydroxyphenylacetate decarboxylase is a [4Fe-4S] cluster containing glycyl radical enzyme proposed to use a glycyl/thiyl radical dyad to catalyze the last step of tyrosine fermentation in clostridia. The decarboxylation product p-cresol (4-methylphenol) is a virulence factor of the human pathogen Clostridium difficile . Here we describe the crystal structures at 1.75 and 1.81 A resolution of substrate-free and substrate-bound 4-hydroxyphenylacetate decarboxylase from the related Clostridium scatologenes . The structures show a (betagamma)(4) tetramer of heterodimers composed of a catalytic beta-subunit harboring the putative glycyl/thiyl dyad and a distinct small gamma-subunit with two [4Fe-4S] clusters at 40 A distance from the active site. The gamma-subunit comprises two domains displaying pseudo-2-fold symmetry that are structurally related to the [4Fe-4S] cluster-binding scaffold of high-potential iron-sulfur proteins. The N-terminal domain coordinates one cluster with one histidine and three cysteines, and the C-terminal domain coordinates the second cluster with four cysteines. Whereas the C-terminal cluster is buried in the betagamma heterodimer interface, the N-terminal cluster is not part of the interface. The previously postulated decarboxylation mechanism required the substrate's hydroxyl group in the vicinity of the active cysteine residue. In contrast to expectation, the substrate-bound state shows a direct interaction between the substrate's carboxyl group and the active site Cys503, while His536 and Glu637 at the opposite side of the active site pocket anchor the hydroxyl group. This state captures a possible catalytically competent complex and suggests a Kolbe-type decarboxylation for p-cresol formation.
  74. Pei, Anna; Oberdorf, William E; Nossa, Carlos W; Chokshi, Pooja; Blaser, Martin J; Yang, Liying; Rosmarin, David M; Pei, Zhiheng. "Diversity of 23S rRNA Genes Within Individual Prokaryotic Genomes" IN: Handbook of molecular microbial ecology. I. Metagenomics and complementary approaches. Hoboken, N.J. : Wiley-Blackwell, 2011. . p.17-28.  (OCLC:729724623-01 #845682)    
  75. Plottel, Claudia S; Blaser, Martin J. "Microbiome and malignancy". Cell Host & Microbe. 2011 Oct 4;10(4):324-335 (MEDL:22018233 #139747)       

    Current knowledge is insufficient to explain why only a proportion of individuals exposed to environmental carcinogens or carrying a genetic predisposition to cancer develop disease. Clearly, other factors must be important, and one such element that has recently received attention is the human microbiome, the residential microbes including Bacteria, Archaea, Eukaryotes, and viruses that colonize humans. Here, we review principles and paradigms of microbiome-related malignancy, as illustrated by three specific microbial-host interactions. We review the effects of the microbiota on local and adjacent neoplasia, present the estrobolome model of distant effects, and discuss the complex interactions with a latent virus leading to malignancy. These are separate facets of a complex biology interfacing all the microbial species we harbor from birth onward toward early reproductive success and eventual senescence
  76. Pohl, Mary Ann; Zhang, William; Shah, Sunny N; Sanabria-Valentin, Edgardo L; Perez-Perez, Guillermo I; Blaser, Martin J. "Genotypic and Phenotypic Variation of Lewis Antigen Expression in Geographically Diverse Helicobacter pylori Isolates". Helicobacter. 2011 Dec;16(6):475-481 (MEDL:22059399 #141081)       

    Background: Helicobacter pylori are a persistent colonizer of the human gastric mucosa, which can lead to the development of peptic ulcer disease and gastric adenocarcinomas. However, H. pylori can asymptomatically colonize a host for years. One factor that has been hypothesized to contribute to such persistence is the production of Lewis (Le) antigens in the lipopolysaccharide layer of the bacterial outer membrane as a form of molecular mimicry, because humans also express these antigens on their gastric mucosa. Humans and H. pylori both are polymorphic for Le expression, which is driven in H. pylori by variation at the Le synthesis loci. In this report, we sought to characterize Le genotypic and phenotypic variation in geographically diverse H. pylori isolates. Materials and Methods: From patients undergoing endoscopy in 29 countries, we determined Le phenotypes of 78 H. pylori strains and performed genotyping of the galT and beta-(1,3)galT loci in 113 H. pylori strains. Results: Le antigen phenotyping revealed a significant (p < .0001) association between type 1 (Le(a) and Le(b) ) expression and strains of East Asian origin. Genotyping revealed a significant correlation between strain origin and the size of the promoter region upstream of the Le synthesis gene, galT (p < .0001). Conclusion: These results indicate that the heterogeneity of human Le phenotypes is reflected in their H. pylori colonizing strains and suggest new loci that can be studied to assess the variation of Le expression
  77. Rhodes, Rosamond; Azzouni, Jody; Baumrin, Stefan Bernard; Benkov, Keith; Blaser, Martin J; Brenner, Barbara; Dauben, Joseph W; Earle, William J; Frank, Lily; Gligorov, Nada; Goldfarb, Joseph; Hirschhorn, Kurt; Hirschhorn, Rochelle; Holzman, Ian; Indyk, Debbie; Jabs, Ethylin Wang; Lackey, Douglas P; Moros, Daniel A; Philpott, Sean; Rhodes, Matthew E; Richardson, Lynne D; Sacks, Henry S; Schwab, Abraham; Sperling, Rhoda; Trusko, Brett; Zweig, Arnulf. "De minimis risk: a proposal for a new category of research risk". American journal of bioethics : AJOB. 2011 Nov;11(11):1-7 (MEDL:22047112 #142151)       
  78. Spellberg, Brad; Blaser, Martin; Guidos, Robert J; Boucher, Helen W; Bradley, John S; Eisenstein, Barry I; Gerding, Dale; Lynfield, Ruth; Reller, L Barth; Rex, John; Schwartz, David; Septimus, Edward; Tenover, Fred C; Gilbert, David N. "Combating antimicrobial resistance: policy recommendations to save lives". Clinical infectious diseases. 2011 May;52 Suppl 5:S397-S428 (MEDL:21474585 #165588)       
  79. Yilmaz P; Kottmann R; Field D; Knight R; Cole JR; Amaral-Zettler L; Gilbert JA; Karsch-Mizrachi I; Johnston A; Cochrane G; Vaughan R; Hunter C; Park J; Morrison N; Rocca-Serra P; Sterk P; Arumugam M; Bailey M; Baumgartner L; Birren BW; Blaser MJ; Bonazzi V; Booth T; Bork P; Bushman FD; Buttigieg PL; Chain PS; Charlson E; Costello EK; Huot-Creasy H; Dawyndt P; Desantis T; Fierer N; Fuhrman JA; Gallery RE; Gevers D; Gibbs RA; Gil IS; Gonzalez A; Gordon JI; Guralnick R; Hankeln W; Highlander S; Hugenholtz P; Jansson J; Kau AL; Kelley ST; Kennedy J; Knights D; Koren O; Kuczynski J; Kyrpides N; Larsen R; Lauber CL; Legg T; Ley RE; Lozupone CA; Ludwig W; Lyons D; Maguire E; Methe BA; Meyer F; Muegge B; Nakielny S; Nelson KE; Nemergut D; Neufeld JD; Newbold LK; Oliver AE; Pace NR; Palanisamy G; Peplies J; Petrosino J; Proctor L; Pruesse E; Quast C; Raes J; Ratnasingham S; Ravel J; Relman DA; Assunta-Sansone S; Schloss PD; Schriml L; Sinha R; Smith MI; Sodergren E; Spor A; Stombaugh J; Tiedje JM; Ward DV; Weinstock GM; Wendel D; White O; Whiteley A; Wilke A; Wortman JR; Yatsunenko T; Glockner FO. "Minimum information about a marker gene sequence (MIMARKS) and minimum information about any (x) sequence (MIxS) specifications". Nature biotechnology. 2011 May 6;29(5):415-420 (MEDL:21552244 #134266)       

    Here we present a standard developed by the Genomic Standards Consortium (GSC) for reporting marker gene sequences-the minimum information about a marker gene sequence (MIMARKS). We also introduce a system for describing the environment from which a biological sample originates. The 'environmental packages' apply to any genome sequence of known origin and can be used in combination with MIMARKS and other GSC checklists. Finally, to establish a unified standard for describing sequence data and to provide a single point of entry for the scientific community to access and learn about GSC checklists, we present the minimum information about any (x) sequence (MIxS). Adoption of MIxS will enhance our ability to analyze natural genetic diversity documented by massive DNA sequencing efforts from myriad ecosystems in our ever-changing biosphere
  80. Blaser, Martin J. "Harnessing the power of the human microbiome [Comment]". Proceedings of the National Academy of Sciences of the United States of America. 2010 Apr 6;107(14):6125-6126 (MEDL:20360554 #109043)       
  81. Blaser, Martin J. "Helicobacter pylori and esophageal disease: wake-up call? [Editorial]". Gastroenterology. 2010 Dec;139(6):1819-1822 (MEDL:21029801 #134409)       
  82. Cook, Michael B; Dawsey, Sanford M; Diaw, Lena; Blaser, Martin J; Perez-Perez, Guillermo I; Abnet, Christian C; Taylor, Philip R; Albanes, Demetrius; Virtamo, Jarmo; Kamangar, Farin. "Serum pepsinogens and Helicobacter pylori in relation to the risk of esophageal squamous cell carcinoma in the alpha-tocopherol, beta-carotene cancer prevention study". Cancer epidemiology biomarkers & prevention. 2010 Aug;19(8):1966-1975 (MEDL:20647397 #134354)       

    BACKGROUND: Helicobacter pylori can induce gastric atrophy in humans, which in turn increases gastric cancer risk. Whether H. pylori and gastric atrophy also affect the risk of esophageal squamous cell carcinoma (ESCC), however, remains unresolved. METHODS: We performed a nested case-control study within the prospective Alpha-Tocopherol, Beta-Carotene Cancer Prevention Study to assess these relationships. The Alpha-Tocopherol, Beta-Carotene Cancer Prevention Study is composed of 29,133 Finnish male smokers, ages 50 to 69 years, who were recruited during 1985-1988. Using baseline sera, we assessed H. pylori status (via immunoglobulin G antibodies against whole-cell and CagA antigens) and gastric atrophy status [via the biomarkers pepsinogen I (PGI) and pepsinogen II (PGII)] in 79 ESCC cases and 94 controls. Logistic regression with adjustment for age, date of blood draw, education, cigarette smoking, alcohol, body mass index, and fruit and vegetable intake was used to estimate odds ratios (OR) and 95% confidence intervals (95% CI). RESULTS: Gastric atrophy (PGI/PGII <4) was associated with ESCC (OR, 4.58; 95% CI, 2.00-10.48). There was no evidence for an association between H. pylori and ESCC (OR, 0.94; 95% CI, 0.40-2.24). CONCLUSIONS: These results could be explained by misclassification of H. pylori status due to serologic amnesia, ESCC risk being dependent on the functional consequences or interactions of H. pylori rather than the infection per se, gastric atrophy having a different histogenesis in ESCC without being primarily dependent on H. pylori acquisition, or a lack of statistical power to detect an effect. IMPACT: Validation of these results may warrant mechanistic studies to determine the route of association between gastric atrophy and ESCC
  83. Dingle, Kate E; Blaser, Martin J; Tu, Zheng-Chao; Pruckler, Janet; Fitzgerald, Collette; van Bergen, Marcel A P; Lawson, Andrew J; Owen, Robert J; Wagenaar, Jaap A. "Genetic relationships among reptilian and mammalian Campylobacter fetus strains determined by multilocus sequence typing". Journal of clinical microbiology. 2010 Mar;48(3):977-980 (MEDL:20053851 #165589)       

    Reptile Campylobacter fetus isolates and closely related strains causing human disease were characterized by multilocus sequence typing. They shared approximately 90% nucleotide sequence identity with classical mammalian C. fetus, and there was evidence of recombination among members of these two groups. The reptile group represents a possible separate genomospecies capable of infecting humans.
  84. Gao, Zhan; Perez-Perez, Guillermo I; Chen, Yu; Blaser, Martin J. "Quantitation of major human cutaneous bacterial and fungal populations". Journal of clinical microbiology. 2010 Oct;48(10):3575-3581 (MEDL:20702672 #114044)       

    Because the human skin microbiota may play roles in the causation or modification of skin diseases, we sought to provide initial quantitative analysis from different cutaneous locations. We developed quantitative PCRs to enumerate the total bacterial and fungal populations, as well as the most common bacterial and fungal genera present in six locales, in eight healthy subjects. We used a set of primers and TaqMan MGB probes based on the bacterial 16S rRNA and fungal internally transcribed spacer region, as well as bacterial genus-specific probes for Propionibacterium, Corynebacterium, Streptococcus, and Staphylococcus and a fungal genus-specific probe for Malassezia. The extent of human DNA contamination of the specimen was determined by quantitating the human housekeeping GAPDH gene. The highest level of 16S rRNA copies of bacteria was present in the axilla (4.44 +/- 0.18 log(10) copies/mul [mean +/- standard error of the mean]), with normalization based on GAPDH levels, but the other five locations were similar to one another (range, 2.48 to 2.89 log(10) copies/mul). There was strong symmetry between the left and right sides. The four bacterial genera accounted for 31% to 59% of total bacteria, with the highest percent composition in the axilla and the lowest in the forearm. Streptococcus was the most common genus present on the forehead and behind the ear. Corynebacterium spp. were predominant in the axilla. Fungal levels were 1 to 2 log(10) lower than for bacteria, with Malassezia spp. accounting for the majority of fungal gene copies. These results provide the first quantitation of the site and host specificities of major bacterial and fungal populations in human skin and present simple methods for their assessment in studies of disease
  85. Jones, Marcus B; Peterson, Scott N; Benn, Rosslyn; Braisted, John C; Jarrahi, Behnam; Shatzkes, Kenneth; Ren, Dacheng; Wood, Thomas K; Blaser, Martin J. "Role of luxS in Bacillus anthracis growth and virulence factor expression". Virulence. 2010 Mar-Apr;1(2):72-83 (MEDL:21178420 #133762)       

    Quorum-sensing (QS), the regulation of bacterial gene expression in response to changes in cell density, involves pathways that synthesize signaling molecules (auto-inducers). The luxS/AI-2-mediated QS system has been identified in both gram-positive and gram-negative bacteria. Bacillus anthracis, the etiological agent of anthrax, possesses genes involved in luxS/AI-2-mediated QS, and deletion of luxS in B. anthracis Sterne strain 34F2 results in inhibition of AI-2 synthesis and a growth defect. In the present study, we created a DeltaluxS B. anthracis strain complemented in trans by insertion of a cassette, including luxS and a gene encoding erythromycin resistance, into the truncated plcR regulator locus. The complemented DeltaluxS strain has restored AI-2 synthesis and wild-type growth. A B. anthracis microarray study revealed consistent differential gene expression between the wild-type and DeltaluxS strain, including downregulation of the B. anthracis S-layer protein gene EA1 and pXO1 virulence genes. These data indicate that B. anthracis may use luxS/AI-2-mediated QS to regulate growth, density-dependent gene expression and virulence factor expression
  86. Lee, In Ohk; Kim, Jie Hyun; Choi, Yeun Jung; Pillinger, Michael H; Kim, Seok-Yong; Blaser, Martin J; Lee, Yong Chan. "Helicobacter pylori CagA phosphorylation status determines the gp130-activated SHP2/ERK and JAK/STAT signal transduction pathways in gastric epithelial cells". Journal of biological chemistry. 2010 May;285(21):16042-16050 (MEDL:20348091 #163511)       

    The Helicobacter pylori protein CagA may undergo tyrosine phosphorylation following its entry into human gastric epithelial cells with downstream effects on signal transduction. Disruption of the gp130 receptor that modulates the balance of the SHP2/ERK and JAK/STAT pathways enhanced peptic ulceration and gastric cancer in gp130 knock-out mice. In this study, we evaluated the effect of translocated CagA in relation to its tyrosine phosphorylation status on the gp130-mediated signal switch between the SHP2/ERK and JAK/STAT3 pathways. We showed that in the presence of CagA, SHP2 was recruited to gp130. Phosphorylated CagA showed enhanced SHP2 binding activity and ERK1/2 phosphorylation, whereas unphosphorylated CagA showed preferential STAT3 activation. These findings indicate that the phosphorylation status of CagA affects the signal switch between the SHP2/ERK and JAK/STAT3 pathways through gp130, providing a novel mechanism to explain H. pylori signaling.
  87. Mane, S P; Dominguez-Bello, M G; Blaser, M J; Sobral, B W; Hontecillas, R; Skoneczka, J; Mohapatra, S K; Crasta, O R; Evans, C; Modise, T; Shallom, S; Shukla, M; Varon, C; Megraud, F; Maldonado-Contreras, A L; Williams, K P; Bassaganya-Riera, J. "Host-interactive genes in Amerindian Helicobacter pylori diverge from their Old World homologs and mediate inflammatory responses". Journal of bacteriology. 2010 Jun;192(12):3078-3092 (MEDL:20400544 #175989)       

    Helicobacter pylori is the dominant member of the gastric microbiota and has been associated with an increased risk of gastric cancer and peptic ulcers in adults. H. pylori populations have migrated and diverged with human populations, and health effects vary. Here, we describe the whole genome of the cag-positive strain V225d, cultured from a Venezuelan Piaroa Amerindian subject. To gain insight into the evolution and host adaptation of this bacterium, we undertook comparative H. pylori genomic analyses. A robust multiprotein phylogenetic tree reflects the major human migration out of Africa, across Europe, through Asia, and into the New World, placing Amerindian H. pylori as a particularly close sister group to East Asian H. pylori. In contrast, phylogenetic analysis of the host-interactive genes vacA and cagA shows substantial divergence of Amerindian from Old World forms and indicates new genotypes (e.g., VacA m3) involving these loci. Despite deletions in CagA EPIYA and CRPIA domains, V225d stimulates interleukin-8 secretion and the hummingbird phenotype in AGS cells. However, following a 33-week passage in the mouse stomach, these phenotypes were lost in isolate V225-RE, which had a 15-kb deletion in the cag pathogenicity island that truncated CagA and eliminated some of the type IV secretion system genes. Thus, the unusual V225d cag architecture was fully functional via conserved elements, but the natural deletion of 13 cag pathogenicity island genes and the truncation of CagA impaired the ability to induce inflammation.
  88. Perez-Perez, Guillermo I; Maw, Anna M; Feingold-Link, Lani; Gunn, Jennifer; Bowers, Andrea L; Minano, Cecilia; Rautelin, Hilpi; Kosunen, Timo U; Blaser, Martin J. "Longitudinal Analysis of Serological Responses of Adults to Helicobacter pylori Antigens". Journal of infectious diseases. 2010 Sep 15;202(6):916-923 (MEDL:20698790 #111828)       

    Because Helicobacter pylori persist for decades in the human stomach, the aim of this study was to examine the long-term course of H. pylori-specific serum immunoglobulin G (IgG) responses with respect to subclass and antigenic target. We studied paired serum samples obtained in 1973 and in 1994 in Vammala, Finland, from 64 healthy H. pylori-positive adults and from other healthy control subjects. H. pylori serum immunoglobulin A, IgG, and IgG subclass responses were determined by antigen-specific enzyme-linked immunosorbent assays. H. pylori-specific IgG1 and IgG4 subtype responses from 47 subjects were similar in 1973 and 1994, but not when compared with unrelated persons. H. pylori-specific IgG1:IgG4 ratios among the participants varied >1000-fold; however, 57 (89.1%) of 64 subjects had an IgG1:IgG4 ratio >1.0, consistent with a predominant IgG1 (Th1) response. Furthermore, ratios in individual hosts were stable over the 21-year period ([Formula: see text]; [Formula: see text]). The immune response to heat shock protein HspA was unchanged in 49 (77%) of the 64 subjects tested; of the 15 whose serostatus changed, all seroconverted and were significantly younger than those whose status did not change. These findings indicate that H. pylori-specific antibody responses are host-specific with IgG1:IgG4 ratios stable over 21 years, IgG1 responses predominating, and HspA seroconversion with aging
  89. Sturt, Amy S; Yang, Liying; Sandhu, Kuldip; Pei, Zhiheng; Cassai, Nicholas; Blaser, Martin J. "Streptococcus gallolyticus subspecies pasteurianus (biotype II/2), a newly reported cause of adult meningitis". Journal of clinical microbiology. 2010 Jun;48(6):2247-2249 (MEDL:20357211 #133500)       

    We report the first case of adult meningitis confirmed to be due to Streptococcus gallolyticus subsp. pasteurianus. Phenotypically reported as Streptococcus bovis biotype II/2, 16S rRNA sequencing revealed S. gallolyticus subsp. pasteurianus. Because of taxonomic uncertainties, S. gallolyticus subsp. pasteurianus may be an underrecognized agent of systemic infections
  90. Webb, G. F.; Hsieh, Y-H.; Wu, J.; Blaser, M. J.. "Pre-symptomatic Influenza Transmission, Surveillance, and School Closings: Implications for Novel Influenza A (H1N1)". Mathematical modelling of natural phenomena. MMNP. 2010 FEB;5(3):191-205 (ISI:000286883500013 #124114)    

    Early studies of the novel swine-origin 2009 influenza A (H1N1) epidemic indicate clinical attack rates in children much higher than in adults. Non-medical interventions such as school closings are constrained by their large socio-economic costs. Here we develop a mathematical model to ascertain the roles of pre-symptomatic influenza transmission as well as symptoms surveillance of children to assess the utility of school closures. Our model analysis indicates that school closings are advisable when pre-symptomatic transmission is significant or when removal of symptomatic children is inefficient. Our objective is to provide a rational basis for school closings decisions dependent on virulence characteristics and local surveillance implementation, applicable to the current epidemic and future epidemics
  91. Atherton, John C; Blaser, Martin J. "Coadaptation of Helicobacter pylori and humans: ancient history, modern implications". Journal of clinical investigation. 2009 Sep;119(9):2475-2487 (MEDL:19729845 #165592)       

    Humans have been colonized by Helicobacter pylori for at least 50,000 years and probably throughout their evolution. H. pylori has adapted to humans, colonizing children and persisting throughout life. Most strains possess factors that subtly modulate the host environment, increasing the risk of peptic ulceration, gastric adenocarcinoma, and possibly other diseases. H. pylori genes encoding these and other factors rapidly evolve through mutation and recombination, changing the bacteria-host interaction. Although immune and physiologic responses to H. pylori also contribute to pathogenesis, humans have evolved in concert with the bacterium, and its recent absence throughout the life of many individuals has led to new human physiological changes. These may have contributed to recent increases in esophageal adenocarcinoma and, more speculatively, other modern diseases.
  92. Baltrus, D A; Blaser, M J; Guillemin, K. "Helicobacter pylori Genome Plasticity". Genome dynamics. 2009;6:75-90 (MEDL:19696495 #133757)       

    Helicobacter pylori, a Gram-negative pathogen associated with ulcers, chronic gastritis, and gastric cancers, has been a resident of the human stomach since early human history [1]. This association has only recently begun to erode with the advent of antibiotics and modern lifestyles, but even today H. pylori colonizes approximately half the world's population. To have remained a successful colonizer of humans during thousands of years of association, populations of H. pylori must have been able to survive and adapt to countless evolutionary challenges within and between hosts. As a species, H. pylori possesses one of the most fluid genomes within the prokaryotic kingdom [2], a characteristic that has likely aided its continued success. H. pylori exhibits exceptionally high rates of DNA point mutations, intragenomic recombination (facilitated by repetitive elements common in H. pylori genomes), and intergenomic recombination (mediated by natural transformation), all of which contribute to the high genomic variability between isolates. Previous reviews have focused on these processes as agents of evolutionary change within H. pylori [2-8]. The mechanisms of both mutation and natural transformation, and the evolutionary processes that retain genetic variation generated by these mechanisms, dictate the extent to which each contributes to genomic diversity in the context of different bacterial population structures [9-13]. Unlike well-studied evolutionary systems, such as Salmonella and Escherichia coli, H. pylori is notable in its lack of an environmental reservoir outside of human and other primate stomachs, suggesting that between-host survival is a relatively weak determinant of selection pressures [14, 15]. Given that H. pylori exist largely as distinct host-associated populations, it is possible to begin to model the evolutionary mechanisms that affect the long-term persistence of this species. In this chapter, we consider how the attributes of H. pylori's natural history as a long-term resident of the human stomach and the specific mechanisms of mutation and genetic exchange in this organism have shaped the H. pylori genome. We begin with a survey of genome plasticity in H. pylori. We then discuss mechanisms of mutation and natural transformation in H. pylori and examine experimental evidence for the generation of genomic changes within populations. Finally, we consider how different models of H. pylori population structure affect the relative contributions of mutation and recombination to the evolutionary success of this organism. By bridging evolutionary studies with investigations of pathogenesis from a molecular perspective, we hope to shed new light on how H. pylori has and continues to evolve with its human hosts
  93. Blaser, Martin J; Falkow, Stanley. "What are the consequences of the disappearing human microbiota?". Nature reviews. Microbiology. 2009 Dec;7(12):887-894 (MEDL:19898491 #105338)       

    Humans and our ancestors have evolved since the most ancient times with a commensal microbiota. The conservation of indicator species in a niche-specific manner across all of the studied human population groups suggests that the microbiota confer conserved benefits on humans. Nevertheless, certain of these organisms have pathogenic properties and, through medical practices and lifestyle changes, their prevalence in human populations is changing, often to an extreme degree. In this Essay, we propose that the disappearance of these ancestral indigenous organisms, which are intimately involved in human physiology, is not entirely beneficial and has consequences that might include post-modern conditions such as obesity and asthma
  94. Chen, Yu; Blaser, Martin J. "Reply to raj et Al [Letter]". Journal of infectious diseases. 2009 Mar 15;199(6):915-916 (MEDL:19239343 #95157)       
  95. Cover, Timothy L; Blaser, Martin J. "Helicobacter pylori in health and disease". Gastroenterology. 2009 May;136(6):1863-1873 (MEDL:19457415 #133687)       

    Helicobacter pylori is highly adapted for colonization of the human stomach and is present in about half of the human population. When present, H pylori is usually the numerically dominant gastric microorganism. H pylori typically does not cause any adverse effects, but it is associated with an increased risk of noncardia gastric adenocarcinoma, gastric lymphoma, and peptic ulcer. Disorders such as esophageal diseases and childhood-onset asthma were recently reported to occur more frequently in individuals who lack H pylori than in H pylori-positive persons. In this review, we discuss biologic factors that allow H pylori to colonize the human stomach, mechanisms by which H pylori increases the risk of peptic ulcer disease and noncardia gastric adenocarcinoma, and potential benefits that H pylori might confer to humans
  96. Hou, Lifang; Savage, Sharon A; Blaser, Martin J; Perez-Perez, Guillermo; Hoxha, Mirjam; Dioni, Laura; Pegoraro, Valeria; Dong, Linda M; Zatonski, Witold; Lissowska, Jolanta; Chow, Wong-Ho; Baccarelli, Andrea. "Telomere length in peripheral leukocyte DNA and gastric cancer risk". Cancer epidemiology biomarkers & prevention. 2009 Nov;18(11):3103-3109 (MEDL:19861514 #165590)       

    Telomere length reflects lifetime cumulative oxidative stress from environmental exposures, such as cigarette smoking and chronic inflammation. Shortened telomere length is thought to cause genomic instability and has been associated with several cancers. We examined the association of telomere length in peripheral leukocyte DNA with gastric cancer risk as well as potential confounding factors and risk modifiers for telomere length-related risk. In a population-based study of gastric cancer conducted in a high-risk population in Warsaw, Poland, between 1994 and 1996, we measured relative telomere length in 300 cases and 416 age- and gender-matched controls using quantitative real-time PCR. Among controls, telomeres were significantly shorter in association with aging (P < 0.001), increasing pack-years of cigarette smoking (P = 0.02), decreasing fruit intake (P = 0.04), and Helicobacter pylori positivity (P = 0.03). Gastric cancer cases had significantly shorter telomere length (mean +/- SD relative telomere length, 1.25 +/- 0.34) than controls (1.34 +/- 0.35; P = 0.0008). Gastric cancer risk doubled [odds ratio (OR), 2.04; 95% confidence interval (95% CI), 1.33-3.13] among subjects in the shortest compared with the highest quartile of telomere length (P(trend) < 0.001). Telomere length-associated risks were higher among individuals with the lowest risk profile, those H. pylori-negative (OR, 5.45; 95% CI, 2.10-14.1), nonsmokers (OR, 3.07; 95% CI, 1.71-5.51), and individuals with high intake of fruits (OR, 2.43; 95% CI, 1.46-4.05) or vegetables (OR, 2.39; 95% CI, 1.51-3.81). Our results suggest that telomere length in peripheral leukocyte DNA was associated with H. pylori positivity, cigarette smoking, and dietary fruit intake. Shortened telomeres increased gastric cancer risk in this high-risk Polish population.
  97. Lin, Edward A; Zhang, Xue-Song; Levine, Steven M; Gill, Steven R; Falush, Daniel; Blaser, Martin J. "Natural transformation of helicobacter pylori involves the integration of short DNA fragments interrupted by gaps of variable size". PLoS pathogens. 2009 Mar;5(3):e1000337-e1000337 (MEDL:19282979 #95156)       

    Helicobacter pylori are gram-negative bacteria notable for their high level of genetic diversity and plasticity, features that may play a key role in the organism's ability to colonize the human stomach. Homeologous natural transformation, a key contributor to genomic diversification, has been well-described for H. pylori. To examine the mechanisms involved, we performed restriction analysis and sequencing of recombination products to characterize the length, fragmentation, and position of DNA imported via natural transformation. Our analysis revealed DNA imports of small size (1,300 bp, 95% confidence limits 950-1850 bp) with instances of substantial asymmetry in relation to selectable antibiotic-resistance markers. We also observed clustering of imported DNA endpoints, suggesting a possible role for restriction endonucleases in limiting recombination length. Additionally, we observed gaps in integrated DNA and found evidence suggesting that these gaps are the result of two or more separate strand invasions. Taken together, these observations support a system of highly efficient short-fragment recombination involving multiple recombination events within a single locus
  98. Pei, Anna; Nossa, Carlos W; Chokshi, Pooja; Blaser, Martin J; Yang, Liying; Rosmarin, David M; Pei, Zhiheng. "Diversity of 23S rRNA genes within individual prokaryotic genomes". PLoS ONE. 2009;4(5):e5437-e5437 (MEDL:19415112 #106442)       

    BACKGROUND: The concept of ribosomal constraints on rRNA genes is deduced primarily based on the comparison of consensus rRNA sequences between closely related species, but recent advances in whole-genome sequencing allow evaluation of this concept within organisms with multiple rRNA operons. METHODOLOGY/PRINCIPAL FINDINGS: Using the 23S rRNA gene as an example, we analyzed the diversity among individual rRNA genes within a genome. Of 184 prokaryotic species containing multiple 23S rRNA genes, diversity was observed in 113 (61.4%) genomes (mean 0.40%, range 0.01%-4.04%). Significant (1.17%-4.04%) intragenomic variation was found in 8 species. In 5 of the 8 species, the diversity in the primary structure had only minimal effect on the secondary structure (stem versus loop transition). In the remaining 3 species, the diversity significantly altered local secondary structure, but the alteration appears minimized through complex rearrangement. Intervening sequences (IVS), ranging between 9 and 1471 nt in size, were found in 7 species. IVS in Deinococcus radiodurans and Nostoc sp. encode transposases. T. tengcongensis was the only species in which intragenomic diversity >3% was observed among 4 paralogous 23S rRNA genes. CONCLUSIONS/SIGNIFICANCE: These findings indicate tight ribosomal constraints on individual 23S rRNA genes within a genome. Although classification using primary 23S rRNA sequences could be erroneous, significant diversity among paralogous 23S rRNA genes was observed only once in the 184 species analyzed, indicating little overall impact on the mainstream of 23S rRNA gene-based prokaryotic taxonomy
  99. Pohl, Mary Ann; Romero-Gallo, Judith; Guruge, Janaki L; Tse, Doris B; Gordon, Jeffrey I; Blaser, Martin J. "Host-dependent Lewis (Le) antigen expression in Helicobacter pylori cells recovered from Leb-transgenic mice". Journal of experimental medicine. 2009 Dec 21;206(13):3061-3072 (MEDL:20008521 #105979)       

    Variation of surface antigen expression is a mechanism used by microbes to adapt to and persist within their host habitats. Helicobacter pylori, a persistent bacterial colonizer of the human stomach, can alter its surface Lewis (Le) antigen expression. We examined H. pylori colonization in mice to test the hypothesis that host phenotype selects for H. pylori (Le) phenotypes. When wild-type and Le(b)-expressing transgenic FVB/N mice were challenged with H. pylori strain HP1, expressing Le(x) and Le(y), we found that bacterial populations recovered after 8 mo from Le(b)-transgenic, but not wild-type, mice expressed Le(b). Changes in Le phenotype were linked to variation of a putative galactosyltransferase gene (beta-(1,3)galT); mutagenesis and complementation revealed its essential role in type I antigen expression. These studies indicate that H. pylori evolves to resemble the host's gastric Le phenotype, and reveal a bacterial genetic locus that is subject to host-driven selection pressure
  100. Shak, Joshua R; Dick, Jonathan J; Meinersmann, Richard J; Perez-Perez, Guillermo I; Blaser, Martin J. "Repeat-associated plasticity in the Helicobacter pylori RD gene family". Journal of bacteriology. 2009 Nov;191(22):6900-6910 (MEDL:19749042 #104893)       

    The bacterium Helicobacter pylori is remarkable for its ability to persist in the human stomach for decades without provoking sterilizing immunity. Since repetitive DNA can facilitate adaptive genomic flexibility via increased recombination, insertion, and deletion, we searched the genomes of two H. pylori strains for nucleotide repeats. We discovered a family of genes with extensive repetitive DNA that we have termed the H. pylori RD gene family. Each gene of this family is composed of a conserved 3' region, a variable mid-region encoding 7 and 11 amino acid repeats, and a 5' region containing one of two possible alleles. Analysis of five complete genome sequences and PCR genotyping of 42 H. pylori strains revealed extensive variation between strains in the number, location, and arrangement of RD genes. Furthermore, examination of multiple strains isolated from a single subject's stomach revealed intrahost variation in repeat number and composition. Despite prior evidence that the protein products of this gene family are expressed at the bacterial cell surface, enzyme-linked immunosorbent assay and immunoblot studies revealed no consistent seroreactivity to a recombinant RD protein by H. pylori-positive hosts. The pattern of repeats uncovered in the RD gene family appears to reflect slipped-strand mispairing or domain duplication, allowing for redundancy and subsequent diversity in genotype and phenotype. This novel family of hypervariable genes with conserved, repetitive, and allelic domains may represent an important locus for understanding H. pylori persistence in its natural host
  101. Zheng, Zongli; Jia, Yanbin; Hou, Lifang; Persson, Christina; Yeager, Meredith; Lissowska, Jolanta; Chanock, Stephen J; Blaser, Martin; Chow, Wong-Ho; Ye, Weimin. "Genetic variation in a4GnT in relation to Helicobacter pylori serology and gastric cancer risk". Helicobacter. 2009 Oct;14(5):120-125 (MEDL:19751437 #165591)       

    BACKGROUND: Helicobacter pylori, a known risk factor of gastric cancer, rarely colonize the deeper portion of normal gastric glands, where the mucus is rich in alpha-1,4-linked N-acetylglucosamine capped O-glycans, that strongly inhibit H. pylori growth in vitro. MATERIALS AND METHODS: We investigated the association between genetic variation in the O-glycan transferase encoding gene (a4GnT) and H. pylori infection and gastric cancer risk using a Polish population-based case-control study (273 gastric cancer patients and 377 controls). RESULTS: A haplotype at the rs2622694-rs397266 locus was associated with H. pylori infection, with the A-A haplotype associated with a higher risk compared with the most frequent G-G haplotype (odds ratio 2.30; 95% confidence interval 1.35-3.92). The association remained significant after correction for multiple tests (global p value: nominal 0.002, empirical 0.045). Neither this haplotype nor the tagSNPs were associated with overall gastric cancer risk. CONCLUSION: a4GnT genetic variation may be relevant to H. pylori infection, but not to gastric cancer risk.
  102. Blaser, Martin J. "Disappearing microbiota: Helicobacter pylori protection against esophageal adenocarcinoma [Comment]". Cancer prevention research (Philadelphia, Pa.). 2008 Oct;1(5):308-311 (MEDL:19138974 #95158)       
  103. Blaser, Martin J. "Understanding microbe-induced cancers". Cancer prevention research (Philadelphia, Pa.). 2008 Jun;1(1):15-20 (MEDL:19138932 #93570)       

    Microbes are important causes of human cancers, and our estimation of their significance continues to grow as cancer biology is better dissected. A classification system is proposed that highlights common and proposed microbe-induced pathways toward oncogenesis, with an emphasis on types of targeted cells and host-microbial interactions. The central principles that underlie oncogenesis induced by the many diverse microbes and the major mechanisms involved are outlined. The phenomenon of microbe-induced cancers raises a number of important biological questions, the solving of which may inform other fields, including aging and degenerative disorders. Finally, our challenge for the future is to better understand the steps in microbe-induced cancers to optimize both prevention and therapy
  104. Blaser, Martin J; Chen, Yu; Reibman, Joan. "Does Helicobacter pylori protect against asthma and allergy?". Gut: journal of the British Society of Gastroenterology. 2008 May;57(5):561-567 (MEDL:18194986 #76054)       

    The microbes that persistently colonize their vertebrate hosts are not accidental (1). Although highly numerous and diverse, there is specificity by site and substantial conservation between individuals. The genus Helicobacter includes spiral, highly motile, urease-positive, gram-negative bacteria that colonize the stomach in many mammals. Each mammal has one or more dominant Helicobacter species and they are highly, if not exclusively, host species-specific (2). Such observations are consistent with the hypothesis that when ancestral mammals diverged from reptiles about 150 million years ago, they contained ancestral helicobacters, which then diverged as their hosts changed. According to this hypothesis, helicobacters represent ancestral biota (flora) in the mammalian stomach. The human-adapted strain is H. pylori (3), which has not been reproducibly observed in any animals other than humans and other primates (3)
  105. Blaser, Martin J; Valentine, Fred T. "Viral commensalism in humans?". Journal of infectious diseases. 2008 Jul 1;198(1):1-3 (MEDL:18544010 #79202)       
  106. Chen, Yu; Blaser, Martin J. "Helicobacter pylori Colonization Is Inversely Associated with Childhood Asthma". Journal of infectious diseases. 2008 Aug 15;198(4):553-560 (MEDL:18598192 #80354)       

    Background. @nbsp; Asthma, a serious health problem worldwide, is becoming more common. Colonization with Helicobacter pylori, a major human indigenous (commensal) microbe, during early life may be relevant to the risk of childhood asthma. Methods. @nbsp; We conducted cross-sectional analyses, using data from 7412 participants in the National Health and Nutrition Examination Survey (NHANES) 1999-2000, to assess the association between H. pylori and childhood asthma. Results. @nbsp; H. pylori seropositivity was inversely associated with onset of asthma before 5 years of age and current asthma in children aged 3-13 years. Among participants 3-19 years of age, the presence of H. pylori was inversely related to ever having had asthma (odds ratio [OR], 0.69; 95% confidence interval [CI], 0.45-1.06), and the inverse association with onset of asthma before 5 years of age was stronger (OR, 0.58; 95% CI, 0.38-0.88). Among participants 3-13 years of age, H. pylori positivity was significantly inversely associated with current asthma (OR, 0.41; 95% CI, 0.24-0.69). H. pylori seropositivity also was inversely related to recent wheezing, allergic rhinitis, and dermatitis, eczema, or rash. Conclusions. @nbsp; This study is the first to report an inverse association between H. pylori seropositivity and asthma in children. The findings indicate new directions for research and asthma prevention
  107. Dominguez-Bello, Maria G; Blaser, Martin J. "Do you have a probiotic in your future?". Microbes & infection. 2008 Jul;10(9):1072-1076 (MEDL:18762263 #95159)       

    The possibility of using microbes to maintain health, and to prevent or treat disease is a topic as old as microbiology. However, one factor impeding the introduction of effective probiotics has been our very limited understanding of the composition of the human microbiome, as well as the biological requirements for these organisms. With advances in understanding the microbiome and its metagenome in humans and other mammals, we now can build a more robust scientific basis to develop probiotic strategies. Increasing knowledge of intramicrobial competition and cooperation, as well as host-microbe cross-signaling, will facilitate design of new probiotics and the modeling of their deployment, leading to eventual clinical trials
  108. Epplein, Meira; Nomura, Abraham M Y; Hankin, Jean H; Blaser, Martin J; Perez-Perez, Guillermo; Stemmermann, Grant N; Wilkens, Lynne R; Kolonel, Laurence N. "Association of Helicobacter pylori infection and diet on the risk of gastric cancer: a case-control study in Hawaii". Cancer causes & control. ccc. 2008 Oct;19(8):869-877 (MEDL:18369531 #79187)       

    OBJECTIVE: The risk factors most strongly associated with gastric cancer are the gastric bacteria Helicobacter pylori and diet. Utilizing data from a case-control study among residents in Hawaii, we examined the association of diet, presence of H. pylori, and non-cardia gastric cancer risk. METHODS: Serum taken at diagnosis for cases (n = 212) and at interview for controls (n = 336) was assayed for IgG antibodies to H. pylori group antigens and to a recombinant fragment of the cytotoxin-associated antigen A (CagA) protein, and subjects completed food frequency questionnaires. Risk measures were calculated using logistic regression. The likelihood ratio test was used to assess interactions. RESULTS: Inverse associations were found between gastric cancer risk and increasing intake of several micronutrients and vegetables among all individuals. For H. pylori/CagA-positive subjects, significant trends were present for total, green, and yellow vegetables, while a significant trend was present only for yellow vegetables among H. pylori/CagA-negative individuals. For intestinal gastric cancer, there was a suggestion that intake of vegetables, especially cruciferous vegetables, had a stronger protective effect for the H. pylori/CagA-positive group. CONCLUSIONS: Diet may play a greater role in the etiology of non-cardia gastric cancer among individuals with evidence of H. pylori infection than among those without
  109. Francois, F; Roper, J; Goodman, A J; Pei, Z; Ghumman, M; Mourad, M; de Perez, A Z Olivares; Perez-Perez, G I; Tseng, C-H; Blaser, M J. "The association of gastric leptin with oesophageal inflammation and metaplasia". Gut: journal of the British Society of Gastroenterology. 2008 Jan;57(1):16-24 (MEDL:17761783 #75709)       

    BACKGROUND: Gastro-oesophageal reflux disease complications may reflect imbalances between protective and injurious factors. Through its effects on cell growth, leptin may influence oesophageal mucosal homeostasis. AIMS: To determine whether leptin receptors are present in the oesophagus, and whether serum or gastric leptin levels are associated with oesophageal inflammation and metaplasia. METHODS: From patients referred for upper endoscopy, biopsies were obtained from the stomach and distal oesophagus, and serum samples were collected. Patients were classified as having normal, inflamed or Barrett's oesophagus. Quantitative immunohistochemistry was performed on representative sections, and leptin levels in plasma and gastric biopsy samples were determined by specific immunoassay. RESULTS: Of 269 individuals enrolled, 105 were Helicobacter pylori-negative. Of the 88 patients with complete oesophageal biopsies, 44 were normal, 24 were inflamed and 20 were Barrett's oesophagus. Receptors for leptin were highly expressed on oesophageal epithelial cells, with similar density and staining pattern in all three conditions, and plasma and antral leptin levels did not differ significantly. Patients with Barrett's had significantly (p = 0.01) higher fundic leptin levels (median 202 (interquartile range 123-333) pg/mg) compared with normal (126 (78-221) pg/mg) or inflamed (114 (76-195) pg/mg) oesophagus. In multivariate analysis, for every twofold increase in fundic leptin, the odds of having Barrett's was 3.4 times (95% CI 1.5 to 7.6) higher compared with having a normal oesophagus. CONCLUSIONS: Leptin receptor expression on oesophageal epithelial cells provides a pathway for leptin-mediated signal transduction. Variation in gastric leptin production could contribute to differential oesophageal healing and metaplasia progression
  110. Gao, Zhan; Tseng, Chi-hong; Strober, Bruce E; Pei, Zhiheng; Blaser, Martin J. "Substantial alterations of the cutaneous bacterial biota in psoriatic lesions". PLoS ONE. 2008;3(7):e2719-e2719 (MEDL:18648509 #86553)       

    For psoriasis, an idiopathic inflammatory disorder of the skin, the microbial biota has not been defined using cultivation-independent methods. We used broad-range 16S rDNA PCR for archaea and bacteria to examine the microbiota of normal and psoriatic skin. From 6 patients, 19 cutaneous samples (13 from diseased skin and 6 from normal skin) were obtained. Extracted DNA was subjected to the broad range PCR, and 1,925 cloned products were compared with 2,038 products previously reported from healthy persons. Using 98% sequence identity as a species boundary, 1,841 (95.6%) clones were similar to known bacterial 16S rDNA, representing 6 phyla, 86 genera, or 189 species-level operational taxonomic unit (SLOTU); 84 (4.4%) clones with <98% identity probably represented novel species. The most abundant and diverse phylum populating the psoriatic lesions was Firmicutes (46.2%), significantly (P<0.001) overrepresented, compared to the samples from uninvolved skin of the patients (39.0%) and healthy persons (24.4%). In contrast, Actinobacteria, the most prevalent and diverse phylum in normal skin samples from both healthy persons (47.6%) and the patients (47.8%), was significantly (P<0.01) underrepresented in the psoriatic lesion samples (37.3%). Representation of Propionibacterium species were lower in the psoriatic lesions (2.9+/-5.5%) than from normal persons (21.1+/-18.2%; P<0.001), whereas normal skin from the psoriatic patients showed intermediate levels (12.3+/-21.6%). We conclude that psoriasis is associated with substantial alteration in the composition and representation of the cutaneous bacterial biota
  111. Godoy-Vitorino, Filipa; Ley, Ruth E; Gao, Zhan; Pei, Zhiheng; Ortiz-Zuazaga, Humberto; Pericchi, Luis R; Garcia-Amado, Maria A; Michelangeli, Fabian; Blaser, Martin J; Gordon, Jeffrey I; Dominguez-Bello, Maria G. "Bacterial community in the crop of the hoatzin, a neotropical folivorous flying bird". Applied & environmental microbiology. 2008 Oct;74(19):5905-5912 (MEDL:18689523 #95160)       

    The hoatzin is unique among known avian species because of the fermentative function of its enlarged crop. A small-bodied flying foregut fermenter is a paradox, and this bird provides an interesting model to examine how diet selection and the gut microbiota contribute to maximizing digestive efficiency. Therefore, we characterized the bacterial population in the crop of six adult hoatzins captured from the wild. A total of 1,235 16S rRNA gene sequences were grouped into 580 phylotypes (67% of the pooled species richness sampled, based on Good's coverage estimator, with C(ACE) and Chao1 estimates of 1,709 and 1,795 species-level [99% identity] operational taxonomic units, respectively). Members of 9 of the approximately 75 known phyla in Bacteria were identified in this gut habitat; the Firmicutes were dominant (67% of sequences, belonging to the classes Clostridia, Mollicutes, and Bacilli), followed by the Bacteroidetes (30%, mostly in the order Bacteroidales), Proteobacteria (1.8%), and Lentisphaerae, Verrucomicrobia, TM7, Spirochaetes, Actinobacteria, and Aminanaerobia (all <0.1%). The novelty in this ecosystem is great; 94% of the phylotypes were unclassified at the 'species' level and thus likely include novel cellulolytic lineages
  112. Iovine, Nicole M; Pursnani, Seema; Voldman, Alex; Wasserman, Gregory; Blaser, Martin J; Weinrauch, Yvette. "Reactive nitrogen species contribute to innate host defense against Campylobacter jejuni". Infection & immunity. 2008 Mar;76(3):986-993 (MEDL:18174337 #76388)       

    Campylobacter jejuni, a gram-negative, invasive organism, is a common cause of food-borne bacterial diarrheal disease. However, the relationship between C. jejuni and the innate immune system is not well described. To better characterize host defense against C. jejuni, we investigated the ability of nitric oxide/reactive nitrogen species to kill two strains of C. jejuni. C. jejuni viability was measured after exposure to reactive nitrogen species produced biochemically as acidified nitrite and by bone marrow-derived macrophages. We report that acidified nitrite caused a 3-log-increased kill of C. jejuni (P < 0.05) at doses that did not affect the viability of Salmonella enterica serovar Typhimurium. Expression of NOS2, the gene responsible for the production of inducible nitric oxide, was increased >100-fold in murine macrophages after incubation with C. jejuni (P < 0.001). These macrophages effected a 2-log-increased kill of C. jejuni over 24 h compared to that by NOS2-/- macrophages unable to produce nitric oxide (P < 0.05). These findings suggest that the mammalian host upregulates the production of nitric oxide in response to exposure to C. jejuni and that nitric oxide and reactive nitrogen species comprise part of the innate defense mechanisms that contribute to the resolution of C. jejuni infection
  113. Kang, Josephine; Blaser, Martin J. "Repair and antirepair DNA helicases in Helicobacter pylori". Journal of bacteriology. 2008 Jun;190(12):4218-4224 (MEDL:18375550 #79203)       

    Orthologs of RecG and RuvABC are highly conserved among prokaryotes; in Escherichia coli, they participate in independent pathways that branch migrate Holliday junctions during recombinational DNA repair. RecG also has been shown to directly convert stalled replication forks into Holliday junctions. The bacterium Helicobacter pylori, with remarkably high levels of recombination, possesses RecG and RuvABC homologs, but in contrast to E. coli, H. pylori RecG limits recombinational repair. We now show that the RuvABC pathway plays the prominent, if not exclusive, repair role. By introducing an E. coli resolvase (RusA) into H. pylori, the repair and recombination phenotypes of the ruvB mutant but not the recG mutant were improved. Our results indicate that RecG and RuvB compete for Holliday junction structures in recombinational repair, but since a classic RecG resolvase is absent from H. pylori, deployment of the RecG pathway is lethal. We propose that evolutionary loss of the H. pylori RecG resolvase provides an 'antirepair' pathway allowing for selection of varied strains. Such competition between repair and antirepair provides a novel mechanism to maximize fitness at a bacterial population level
  114. Meinersmann, Richard J; Romero-Gallo, Judith; Blaser, Martin J. "Rate heterogeneity in the evolution of Helicobacter pylori and the behavior of homoplastic sites". Infection, Genetics & Evolution. 2008 Sep;8(5):593-602 (MEDL:18571992 #95161)       

    Helicobacter pylori are bacteria with substantial inter-strain variability and phylogenetic reconstructions of sequence data from the organism have common homoplastic sites. Although frequent recombination events have been proposed to contribute to the variation, the effects of nucleotide substitution rate heterogeneities on the reconstruction of H. pylori genealogies have not been studied. We analyzed the substitution pattern of a housekeeping gene, a homologue of the ribonuclease reductase gene (rnr), to characterize rate heterogeneities between 11 H. pylori isolates. Evidence of limited recombination was demonstrated by the Sawyer's runs test, but the homoplasy test and site-by-site compatibility tests indicated frequent recombination events. Within the 1935 nucleotide gene, 292 sites were polymorphic with an average pair-wise difference of 5.01%. Xia's distances for amino acids at non-synonymous codon substitution sites were smaller at homoplastic sites than at sites that were not homoplastic. Transitions were significantly more common among homoplastic than among non-homoplastic nucleotide substitutions. Simulations of evolution with or without recombination indicated the transition/transversion ratio is expected to be higher in homoplastic sites with no recombination. Despite evidence of recombination, analyses of the rnr genealogy does not show a random tree but rather base substitution behaviors characteristic of both recombination and substitution saturation at some sites. Analyses of sequences in the H. pylori multilocus sequence-typing database provided similar evidence for substitution saturation in multiple housekeeping genes
  115. Nachamkin, Irving; Blaser, Martin J. Campylobacter. Washington DC : ASM Press, 2008. xv, 716 p. ; 29cm.   3rd ed    
  116. Paulino, Luciana C; Tseng, Chi-Hong; Blaser, Martin J. "Analysis of Malassezia microbiota in healthy superficial human skin and in psoriatic lesions by multiplex real-time PCR". FEMS yeast research. 2008 May;8(3):460-471 (MEDL:18294199 #79204)       

    Yeasts from the genus Malassezia are members of the normal biota of human skin, and may play a role in dermatopathology. Our previous study of the fungal microbiota from healthy subjects and from patients with psoriasis using clone library analysis revealed the presence of five Malassezia species and four uncharacterized phylotypes. We now compared the Malassezia microbiota from six healthy body locations and two psoriatic lesions, and evaluated its stability over time using multiplex real-time PCR. Samples from each body location were obtained monthly, for 4 months. Dual-labeled probes were designed to recognize four Malassezia sp. and two uncharacterized groups, and a genus-specific probe was also developed. A good correspondence was obtained between real-time PCR data and clone library analyses. Malassezia restricta was the most abundant species in the majority of samples, and high amounts of Malassezia globosa were also detected. The uncharacterized phylotype 1 was usually detected in lower proportions, nevertheless it was present in most samples. The microbiota was host-specific and relatively stable over time. In accordance with our previous observations, no significant dichotomy between samples from healthy skin and from psoriatic lesions was found; the samples clustered according to the subject, rather than health status
  117. Reibman, Joan; Marmor, Michael; Filner, Joshua; Fernandez-Beros, Maria-Elena; Rogers, Linda; Perez-Perez, Guillermo I; Blaser, Martin J. "Asthma is inversely associated with Helicobacter pylori status in an urban population". PLoS ONE. 2008;3(12):e4060-e4060 (MEDL:19112508 #91964)       

    BACKGROUND: Microbial exposures have been suggested to confer protection from allergic disorders and reduced exposures to gastrointestinal microbiota have been proposed as an explanation for the increase in asthma prevalence. Since the general prevalence of Helicobacter pylori has been decreasing, we hypothesized that H. pylori serostatus would be inversely related to the presence of asthma. METHODS: Adults were recruited to participate in the New York University (NYU)/Bellevue Asthma Registry in New York City. Adult asthma cases (N = 318) and controls (N = 208) were identified and serum IgG antibodies to H. pylori whole cell antigens or the immunodominant CagA antigen were measured. RESULTS: As expected, the asthma cases and controls differed with respect to atopy and lung function. Seropositivity to H. pylori or CagA antigen was present in 47.1% of the total case and control study population. Asthma was inversely associated with CagA seropositivity (OR = 0.57, 95% CI = 0.36-0.89). Median age of onset of asthma (doctor's diagnosis) was older (21 years) among individuals with CagA+ strains than among H. pylori- individuals (11 years) (p = 0.006). CONCLUSION: These data are consistent with the hypothesis that colonization with CagA+ H. pylori strains is inversely associated with asthma and is associated with an older age of asthma onset in an urban population. The data suggest H. pylori as a marker for protection
  118. Roper, Jatin; Francois, Fritz; Shue, Peter L; Mourad, Michelle S; Pei, Zhiheng; Olivares de Perez, Asalia Z; Perez-Perez, Guillermo I; Tseng, Chi-Hong; Blaser, Martin J. "Leptin and ghrelin in relation to Helicobacter pylori status in adult males". Journal of clinical endocrinology & metabolism. 2008 Jun;93(6):2350-2357 (MEDL:18397989 #159212)       

    CONTEXT: Leptin and ghrelin, hormones involved in human energy homeostasis, are both produced in the stomach. OBJECTIVE: We sought to determine whether the presence of Helicobacter pylori affects gastric and systemic levels of leptin and ghrelin. DESIGN, SETTING, AND PATIENTS: We consecutively enrolled 256 patients referred for upper endoscopy at a Veterans Affairs outpatient endoscopy center. OUTCOMES: We obtained fasting serum, fundic and antral biopsies, and gastric juice. Based on histological, biochemical, and serological assays, patients were categorized as H. pylori+ or H. pylori-. Leptin and total ghrelin levels in serum, gastric biopsies, and gastric juice were determined by specific ELISAs. RESULTS: Of the 256 subjects, 120 were H. pylori+ and 96 were H. pylori-; 40 patients of indeterminate status were excluded. Serum and fundic leptin levels correlated with body mass index in the H. pylori+ (r = 0.35; P < 0.0001 and r = 0.35; P < 0.0001, respectively) and H. pylori- (r = 0.65; P < 0.0001 and r = 0.41; P < 0.0001, respectively) groups, but H. pylori+ subjects had significantly lower serum leptin levels [median 2.2 ng/ml (interquartile range 0.9-4.6) vs. 4.0 ng/ml (1.7-7.2); P = 0.0003]. Serum ghrelin levels were similar in the H. pylori+ and H. pylori- groups [median 1651 pg/ml (interquartile range 845-2247) vs. 1629 pg/ml (992-2886); P = 0.23]. H. pylori status did not significantly affect gastric biopsy leptin and ghrelin levels. Ghrelin levels in gastric juice varied over 4 log(10) (<80-776,000 pg/ml) and correlated with gastric juice pH in the H. pylori+ group (r = 0.68; P < 0.0001). CONCLUSIONS: These findings provide evidence that H. pylori status affects leptin and ghrelin homeostasis, presumably via intragastric interactions.
  119. Shak, Joshua R; Roper, Jatin; Perez-Perez, Guillermo I; Tseng, Chi-hong; Francois, Fritz; Gamagaris, Zoi; Patterson, Carlie; Weinshel, Elizabeth; Fielding, George A; Ren, Christine; Blaser, Martin J. "The Effect of Laparoscopic Gastric Banding Surgery on Plasma Levels of Appetite-Control, Insulinotropic, and Digestive Hormones". Obesity surgery. 2008 Sep;18(9):1089-1096 (MEDL:18408980 #78623)       

    BACKGROUND: We hypothesized that laparoscopic adjustable gastric banding (LAGB) reduces weight and modulates ghrelin production, but largely spares gastrointestinal endocrine function. To examine this hypothesis, we determined plasma concentrations of appetite-control, insulinotropic, and digestive hormones in relation to LAGB. METHODS: Twenty-four patients undergoing LAGB were prospectively enrolled. Body mass index (BMI) was measured and blood samples obtained at baseline and 6 and 12 months post-surgery. Plasma concentrations of leptin, acylated and total ghrelin, pancreatic polypeptide (PP), insulin, glucose-dependent insulinotropic peptide (GIP), active glucagon-like peptide-1 (GLP-1), gastrin, and pepsinogens I and II were measured using enzyme-linked immunoassays. RESULTS: Median percent excess weight loss (%EWL) over 12 months was 45.7% with median BMI decreasing from 43.2 at baseline to 33.8 at 12 months post-surgery (p < 0.001). Median leptin levels decreased from 19.7 ng/ml at baseline to 6.9 ng/ml at 12 months post-surgery (p < 0.001). In contrast, plasma levels of acylated and total ghrelin, PP, insulin, GIP, GLP-1, gastrin, and pepsinogen I did not change in relation to surgery (p > 0.05). Pepsinogen II levels were significantly lower 6 months after LAGB but returned to baseline levels by 12 months. CONCLUSIONS: LAGB yielded substantial %EWL and a proportional decrease in plasma leptin. Our results support the hypothesis that LAGB works in part by suppressing the rise in ghrelin that normally accompanies weight loss. Unchanged concentrations of insulinotropic and digestive hormones suggest that gastrointestinal endocrine function is largely maintained in the long term
  120. Blaser, Martin J; Kirschner, Denise. "The equilibria that allow bacterial persistence in human hosts". Nature. 2007 Oct 18;449(7164):843-849 (MEDL:17943121 #75392)       

    We propose that microbes that have developed persistent relationships with human hosts have evolved cross-signalling mechanisms that permit homeostasis that conforms to Nash equilibria and, more specifically, to evolutionarily stable strategies. This implies that a group of highly diverse organisms has evolved within the changing contexts of variation in effective human population size and lifespan, shaping the equilibria achieved, and creating relationships resembling climax communities. We propose that such ecosystems contain nested communities in which equilibrium at one level contributes to homeostasis at another. The model can aid prediction of equilibrium states in the context of further change: widespread immunodeficiency, changing population densities, or extinctions
  121. Blaser, Martin J; Nomura, Abraham; Lee, James; Stemmerman, Grant N; Perez-Perez, Guillermo I. "Early-life family structure and microbially induced cancer risk". PLoS medicine. 2007 Jan;4(1):e7-e7 (MEDL:17227131 #79193)       

    BACKGROUND: Cancer may follow exposure to an environmental agent after many decades. The bacterium Helicobacter pylori, known to be acquired early in life, increases risk for gastric adenocarcinoma, but other factors are also important. In this study, we considered whether early-life family structure affects the risk of later developing gastric cancer among H. pylori+ men. METHODS AND FINDINGS: We examined a long-term cohort of Japanese-American men followed for 28 y, and performed a nested case-control study among those carrying H. pylori or the subset carrying the most virulent cagA+ H. pylori strains to address whether family structure predicted cancer development. We found that among the men who were H. pylori+ and/or cagA+ (it is possible to be cagA+ and H. pylori- if the H. pylori test is falsely negative), belonging to a large sibship or higher birth order was associated with a significantly increased risk of developing gastric adenocarcinoma late in life. For those with cagA+ strains, the risk of developing gastric cancer was more than twice as high (odds ratio 2.2; 95% confidence interval 1.2-4.0) among those in a sibship of seven or more individuals than in a sibship of between one and three persons. CONCLUSIONS: These results provide evidence that early-life social environment plays a significant role in risk of microbially induced malignancies expressing five to eight decades later, and these findings lead to new models to explain these interactions
  122. Chen, Yu; Blaser, Martin J. "Inverse Associations of Helicobacter pylori With Asthma and Allergy". Archives of internal medicine. 2007 Apr 23;167(8):821-827 (MEDL:17452546 #71638)       

    BACKGROUND: Acquisition of Helicobacter pylori, which predominantly occurs before age 10 years, may reduce risks of asthma and allergy. METHODS: We evaluated the associations of H pylori status with history of asthma and allergy and with skin sensitization using data from 7663 adults in the Third National Health and Nutrition Examination Survey. Adjusted odds ratios (ORs) for currently and ever having asthma, allergic rhinitis, allergy symptoms in the previous year, and allergen-specific skin sensitization were computed comparing participants seropositive for cagA(-) or cagA(+) strains of H pylori with those without H pylori. RESULTS: The presence of cagA(+) H pylori strains was inversely related to ever having asthma (OR, 0.79; 95% confidence interval [CI], 0.63-0.99), and the inverse association of cagA positivity with childhood-onset (age </=15 years) asthma was stronger (OR, 0.63; 95% CI, 0.43-0.93) than that with adult-onset asthma (OR, 0.97; 95% CI, 0.72-1.32). Colonization with H pylori, especially with a cagA(+) strain, was inversely associated with currently (OR, 0.77; 95% CI, 0.62-0.96) or ever (OR, 0.77; 95% CI, 0.62-0.94) having a diagnosis of allergic rhinitis, especially for childhood onset (OR, 0.55; 95% CI, 0.37-0.82). Consistent inverse associations were found between H pylori colonization and the presence of allergy symptoms in the previous year and sensitization to pollens and molds. CONCLUSION: These observations support the hypothesis that childhood acquisition of H pylori is associated with reduced risks of asthma and allergy
  123. Daskalakis, Demetre C; Blaser, Martin J. "Another perfect storm: Shigella, men who have sex with men, and HIV [Editorial]". Clinical infectious diseases. 2007 Feb 1;44(3):335-337 (MEDL:17205437 #78759)       
  124. Dingle, KE; Blaser, MJ; Tu, ZC; Pruckler, J; Fitzgerald, C; Van Bergen, MA; Lawson, AJ; Owen, RJ; Wagenaar, JA. "Characterization of Campylobacter fetus strains originating in reptiles and closely related human strains by multilocus sequence typing [Meeting Abstract]". Zoonoses & public health. 2007 JAN;54(1):76-76 (ISI:000250519200252 #87168)    
  125. Gao, Zhan; Tseng, Chi-hong; Pei, Zhiheng; Blaser, Martin J. "Molecular analysis of human forearm superficial skin bacterial biota". Proceedings of the National Academy of Sciences of the United States of America. 2007 Feb 20;104(8):2927-2932 (MEDL:17293459 #71419)       

    The microbial ecology of human skin is complex, but little is known about its species composition. We examined the diversity of the skin biota from the superficial volar left and right forearms in six healthy subjects using broad-range small subunit rRNA genes (16S rDNA) PCR-based sequencing of randomly selected clones. For the initial 1,221 clones analyzed, 182 species-level operational taxonomic units (SLOTUs) belonging to eight phyla were identified, estimated as 74.0% [95% confidence interval (C.I.), approximately 64.8-77.9%] of the SLOTUs in this ecosystem; 48.0 +/- 12.2 SLOTUs were found in each subject. Three phyla (Actinobacteria, Firmicutes, and Proteobacteria) accounted for 94.6% of the clones. Most (85.3%) of the bacterial sequences corresponded to known and cultivated species, but 98 (8.0%) clones, comprising 30 phylotypes, had <97% similarity to prior database sequences. Only 6 (6.6%) of the 91 genera and 4 (2.2%) of the 182 SLOTUs, respectively, were found in all six subjects. Analysis of 817 clones obtained 8-10 months later from four subjects showed additional phyla (numbering 2), genera (numbering 28), and SLOTUs (numbering 65). Only four (3.4%) of the 119 genera (Propionibacteria, Corynebacteria, Staphylococcus, and Streptococcus) were observed in each subject tested twice, but these genera represented 54.4% of all clones. These results show that the bacterial biota in normal superficial skin is highly diverse, with few well conserved and well represented genera, but otherwise low-level interpersonal consensus
  126. Ghose, Chandrabali; Perez-Perez, Guillermo I; Torres, Victor J; Crosatti, Marialuisa; Nomura, Abraham; Peek, Richard M Jr; Cover, Timothy L; Francois, Fritz; Blaser, Martin J. "Serological Assays for Identification of Human Gastric Colonization by Helicobacter pylori Strains Expressing VacA m1 or m2". Clinical & vaccine immunology. 2007 Apr;14(4):442-450 (MEDL:17267587 #71774)       

    The Helicobacter pylori vacA gene encodes a secreted protein (VacA) that alters the function of gastric epithelial cells and T lymphocytes. H. pylori strains containing particular vacA alleles are associated with differential risk of disease. Because the VacA midregion may exist as one of two major types, m1 or m2, serologic responses may potentially be used to differentiate between patients colonized with vacA m1- or vacA m2-positive H. pylori strains. In this study, we examined the utility of specific antigens from the m regions of VacA as allele-specific diagnostic antigens. We report that serological responses to P44M1, an H. pylori m1-specific antigen, are observed predominantly in patients colonized with m1-positive strains, whereas responses to VacA m2 antigens, P48M2 and P55M2, are observed in patients colonized with either m1- or m2-positive strains. In an Asian-American population, serologic responses to VacA m region-specific antigens were not able to predict the risk of development of gastric cancer
  127. Kamangar, F; Qiao, Y-L; Blaser, M J; Sun, X-D; Katki, H; Fan, J-H; Perez-Perez, G I; Abnet, C C; Zhao, P; Mark, S D; Taylor, P R; Dawsey, S M. "Helicobacter pylori and oesophageal and gastric cancers in a prospective study in China". British journal of cancer. 2007 Jan;96(1):172-176 (MEDL:17179990 #416872)       

    In a cohort of 29,584 residents of Linxian, China, followed from 1985 to 2001, we conducted a case-cohort study of the magnitude of the association of Helicobacter pylori seropositivity with cancer risk in a random sample of 300 oesophageal squamous cell carcinomas, 600 gastric cardia adenocarcinomas, all 363 diagnosed gastric non-cardia adenocarcinomas, and a random sample of the entire cohort (N=1050). Baseline serum was evaluated for IgG antibodies to whole-cell and CagA H. pylori antigens by enzyme-linked immunosorbent assay. Risks of both gastric cardia and non-cardia cancers were increased in individuals exposed to H. pylori (Hazard ratios (HRs) and 95% confidence intervals=1.64; 1.26-2.14, and 1.60; 1.15-2.21, respectively), whereas risk of oesophageal squamous cell cancer was not affected (1.17; 0.88-1.57). For both cardia and non-cardia cancers, HRs were higher in younger individuals. With longer time between serum collection to cancer diagnosis, associations became stronger for cardia cancers but weaker for non-cardia cancers. CagA positivity did not modify these associations. The associations between H. pylori exposure and gastric cardia and non-cardia adenocarcinoma development were equally strong, in contrast to Western countries, perhaps due to the absence of Barrett's oesophagus and oesophageal adenocarcinomas in Linxian, making all cardia tumours of gastric origin, rather than a mixture of gastric and oesophageal malignancies.
  128. Levine, Steven M; Lin, Edward A; Emara, Walid; Kang, Josephine; DiBenedetto, Michael; Ando, Takafumi; Falush, Daniel; Blaser, Martin J. "Plastic cells and populations: DNA substrate characteristics in Helicobacter pylori transformation define a flexible but conservative system for genomic variation". FASEB journal. 2007 Nov;21(13):3458-3467 (MEDL:17567566 #75362)       

    Helicobacter pylori, bacteria that colonize the human gastric mucosa, are naturally competent for transformation by exogenous DNA, and show a panmictic population structure. To understand the mechanisms involved in its horizontal gene transfer, we sought to define the interval required from exposure to substrate DNA until DNA uptake and expression of a selectable phenotype, as well as the relationship of transforming fragment length, concentration, homology, symmetry, and strandedness, to the transformation frequency. We provide evidence that natural transformation in H. pylori differs in efficiency among wild-type strains but is saturable and varies with substrate DNA length, symmetry, strandedness, and species origin. We show that H. pylori cells can be transformed within one minute of contact with DNA, by DNA fragments as small as 50 bp, and as few as 5 bp on one flank of a selectable single nucleotide mutation is sufficient substrate for recombination of a transforming fragment, and that double-stranded DNA is the preferred (1000-fold >single-stranded) substrate. The high efficiency of double-stranded DNA as transformation substrate, in conjunction with strain-specific restriction endonucleases suggests a model of short-fragment recombination favoring closest relatives, consistent with the observed H. pylori population biology
  129. Marini, Elisabetta; Maldonado-Contreras, Ana L; Cabras, Stefano; Hidalgo, Glida; Buffa, Roberto; Marin, Aura; Floris, Giovanni; Racugno, Walter; Pericchi, Luis R; Castellanos, Maria E; Groschl, Michael; Blaser, Martin J; Dominguez-Bello, Maria G. "Helicobacter pylori and intestinal parasites are not detrimental to the nutritional status of Amerindians". American journal of tropical medicine & hygiene. 2007 Mar;76(3):534-540 (MEDL:17360880 #79205)    

    Gastrointestinal parasites have evolved with humans and colonize many asymptomatic subjects. We investigated the influence of microbial gastrointestinal colonization on the nutritional status of rural Amerindians (40 males and 61 females). Helicobacter pylori was detected by 13C-breath test, and intestinal parasites were detected in fecal specimens. Body morphometry and bioelectrical impedance measurements were measured. Although Amerindians showed low height and weight for age, they had an adequate body mass index, morphometric parameters, and cell mass. Intestinal parasites were detected in 99% of the subjects, with no detrimental effect on nutritional parameters. Helicobacter pylori was present in 82% of adults and half the children, and was positively correlated with improved nutritional status. Despite the high prevalence of gastrointestinal microbes often associated with disease, the studied population of Amerindians had a body morphometry and composition indicative of good nutritional status, and improved in children positive for gastric H. pylori
  130. Pillinger, Michael H; Blaser, Martin J. "The language used by Helicobacter pylori to regulate human cells [Editorial]". Journal of infectious diseases. 2007 Jul 1;196(1):6-9 (MEDL:17538876 #73298)       
  131. Pillinger, Michael H; Marjanovic, Nada; Kim, Seok-Yong; Lee, Yong-Chan; Scher, Jose U; Roper, Jatin; Abeles, Aryeh M; Izmirly, Peter I; Axelrod, Matthew; Pillinger, Mara Y; Tolani, Sonia; Dinsell, Victoria; Abramson, Steven B; Blaser, Martin J. "Helicobacter pylori stimulates gastric epithelial cell MMP-1 secretion via CagA-dependent and -independent ERK activation". Journal of biological chemistry. 2007 Jun 29;282(26):18722-18731 (MEDL:17475625 #73947)       

    Because the mechanisms of Helicobacter pylori-induced gastric injury are incompletely understood, we examined the hypothesis that H. pylori induces matrix metalloproteinase-1 (MMP-1) secretion, with potential to disrupt gastric stroma. We further tested the role of CagA, an H. pylori virulence factor, in MMP-1 secretion. Co-incubation of AGS cells with Tx30a, an H. pylori strain lacking the cagA virulence gene, stimulated MMP-1 secretion, confirming cagA-independent secretion. Co-incubation with strain 147C (cagA(+)) resulted in CagA translocation into AGS cells and increased MMP-1 secretion relative to Tx30a. Transfection of cells with the recombinant 147C cagA gene also induced MMP-1 secretion, indicating that CagA can independently stimulate MMP-1 secretion. Co-incubation with strain 147A, containing a cagA gene that lacks an EPIYA tyrosine phosphorylation motif, as well as transfection with 147A cagA, yielded an MMP-1 secretion intermediate between no treatment and 147C, indicating that CagA tyrosine phosphorylation regulates cellular signaling in this model system. H. pylori induced activation of the MAP kinase ERK, with CagA-independent (early) and dependent (later) components. MEK inhibitors UO126 and PD98059 inhibited both CagA-independent and -dependent MMP-1 secretion, whereas p38 inhibition enhanced MMP-1 secretion and ERK activation, suggesting p38 negative regulation of MMP-1 and ERK. These data indicate H. pylori effects on host epithelial MMP-1 expression via ERK, with p38 playing a potential regulatory role
  132. Sanabria-Valentin, Edgardo; Colbert, Marie-Teresa C; Blaser, Martin J. "Role of futC slipped strand mispairing in Helicobacter pylori Lewisy phase variation". Microbes & infection. 2007 Nov-Dec;9(14-15):1553-1560 (MEDL:18024122 #76143)       

    The O antigen of the Helicobacter pylori lipopolysaccharide is composed of repeating units of fucosylated Lewis (Le) antigens. The alpha(1,2)-fucosyltransferase (futC) of H. pylori, which catalyzes the conversion of Le(x) to Le(y) by addition of fucose, is subject to slipped-strand mispairing involving a homonucleotide (poly-C) tract. To explore the distribution of Le phenotypes within H. pylori cells grown in vitro, 379 single colonies of strain J166 were examined for Le expression. Two major populations with reciprocal Le(x)/Le(y) phenotypes were identified. Phenotypes correlated with futC frame status, suggesting that strain J166 represents a mixed population with respect to futC poly-C tract length, which was confirmed by a translational reporter. After hundreds of generations in vitro, phenotypes did not change significantly, indicating that the observed J166 Le diversity reflects the founding population. Since slipped-strand mispairing in the futC poly-C tract was postulated to explain the Le(y) phenotypic change observed in J166 derivative strain 98-169 isolated 10 months after rhesus monkey challenge, in trans complementation with in-frame futC was performed. Le(y) synthesis was restored and Le(x) expression was reciprocally lowered. From these studies, we confirmed the principal role of futC slipped-strand mispairing in Le antigenic variation in vitro and in vivo
  133. Sanabria-Valentin, EL; Blaser, MJ. "Role of futC slipped strand mispairing in Helicobacter pylori Lewis(y) phase variation during rhesus monkey challenge [Meeting Abstract]". Zoonoses & public health. 2007 JAN;54(1):57-57 (ISI:000250519200182 #87167)    
  134. Young, B; Roper, H; Mourad, M; Olivares de Perez, AZ; Perez-Perez, GI; Pei, ZH; Blaser, MJ; Francois, F. "Fasting gastric leptin levels are elevated in diabetics independent of BMI [Meeting Abstract]". American journal of gastroenterology. 2007 SEP;102(6):S163-S163 (ISI:000249397800125 #74153)    
  135. Bik, Elisabeth M; Eckburg, Paul B; Gill, Steven R; Nelson, Karen E; Purdom, Elizabeth A; Francois, Fritz; Perez-Perez, Guillermo; Blaser, Martin J; Relman, David A. "Molecular analysis of the bacterial microbiota in the human stomach". Proceedings of the National Academy of Sciences of the United States of America. 2006 Jan 17;103(3):732-737 (MEDL:16407106 #62128)       

    The microbiota of the human stomach and the influence of Helicobacter pylori colonization on its composition remain largely unknown. We characterized bacterial diversity within the human gastric mucosa by using a small subunit 16S rDNA clone library approach and analyzed 1,833 sequences generated by broad-range bacterial PCR from 23 gastric endoscopic biopsy samples. A diverse community of 128 phylotypes was identified, featuring diversity at this site greater than previously described. The majority of sequences were assigned to the Proteobacteria, Firmicutes, Actinobacteria, Bacteroidetes, and Fusobacteria phyla. Ten percent of the phylotypes were previously uncharacterized, including a Deinococcus-related organism, relatives of which have been found in extreme environments but not reported before in humans. The gastric clone libraries from 19 subjects contained H. pylori rDNA; however, only 12 of these subjects tested positive for H. pylori by conventional laboratory methods. Statistical analysis revealed a large degree of intersubject variability of the gastric ecosystem. The presence of H. pylori did not affect the composition of the gastric community. This gastric bacterial rDNA data set was significantly different from sequence collections of the human mouth and esophagus described in other studies, indicating that the human stomach may be home to a distinct microbial eco-system. The gastric microbiota may play important, as-yet-undiscovered roles in human health and disease
  136. Blaser, Martin J. Wei chang dao gan ran = [Infections of the gastroenterological tract]. Bei jing : Ren min wei sheng chu ban she, 2006. ?.     
  137. Blaser, Martin J. "Microbes adapt to inner space [Comment]". Nature medicine. 2006 Sep;12(9):994-996 (MEDL:16960568 #79208)       
  138. Blaser, Martin J. "Pandemics and preparations [Editorial]". Journal of infectious diseases. 2006 Nov 1;194 Suppl 2:S70-S72 (MEDL:17163391 #79206)       
  139. Blaser, Martin J. "Who are we? Indigenous microbes and the ecology of human diseases". EMBO reports. 2006 Oct;7(10):956-960 (MEDL:17016449 #69595)       
  140. Chang, Ya-Jen; Wu, Ming-Shiang; Lin, Jaw-Town; Pestell, Richard G; Blaser, Martin J; Chen, Ching-Chow. "Mechanisms for Helicobacter pylori CagA-induced cyclin D1 expression that affect cell cycle". Cellular microbiology. 2006 Nov;8(11):1740-1752 (MEDL:16759223 #79210)       

    Particular Helicobacter pylori genotypes differentially induce epithelial cell proliferation, but the mechanisms are not characterized. We explored the effect of H. pylori CagA on expression of cyclin D1, an important cell cycle regulator. H. pylori-induced cell survival and cyclin D1 expression were attenuated in a cagA mutant. AP1 and cAMP response element (CRE), but not NF-kappaB, were involved in the induced cyclin D1 expression. Diminished mitogen-activated protein kinase (MAPK) activation, especially involving p38, with downstream effects on AP1 and CRE activation, was observed for the cagA mutant. In total, these data show that cagA+ H. pylori strains are enhanced in their ability to activate MAPKs and downstream transcription factors, increasing cyclin D1 expression, G1-S phase progression, and host cell survival, explaining both the preferential survival of affected host cells, and the enhanced oncogenesis by these bacteria
  141. Emura, Fabian; Saito, Daizo; Kakizoe, Tadao; Blaser, Martin J. "Infection, cancer and prevention: report of the 19th International Symposium of the Foundation for Promotion of Cancer Research". Japanese journal of clinical oncology. 2006 Nov;36(11):745-755 (MEDL:17158271 #79207)       
  142. Francois, Fritz; Blaser, Martin J. "Improving Helicobacter pylori eradication regimens [Editorial]". Annals of internal medicine. 2006 Jan 17;144(2):140-141 (MEDL:16418415 #62127)    
  143. Huang, S; Kang, Josephine; Sanabria-Valentin, EL; Blaser, Martin J. "Antimutator role of DNA glycosylase mutY and its phase-variation in Helicobacter pylori [Meeting Abstract]". Abstracts of the ... general meeting of the American Society for Microbiology. 2006;106:177-177 (BCI:BCI200800233407 #820082)    
  144. Huang, Shuyan; Kang, Josephine; Blaser, Martin J. "Antimutator role of the DNA glycosylase mutY gene in Helicobacter pylori". Journal of bacteriology. 2006 Sep;188(17):6224-6234 (MEDL:16923889 #68780)       

    Helicobacter pylori has a highly variable genome with ongoing diversification via inter- and intragenomic recombination and spontaneous mutation. DNA repair genes modulating mutation and recombination rates that influence diversification have not been well characterized for H. pylori. To examine the role of putative base excision repair ung and mutY glycosylase and xthA apurinic/apyrimidinic endonuclease genes in H. pylori, mutants of each were constructed in strain JP26 by allelic exchange. Spontaneous mutation frequencies of JP26 mutY mutants, assessed by rifampin resistance, were consistently higher (26-fold) than that of the wild type, whereas the ung and xthA mutants showed smaller increases. In trans complementation of the JP26 mutY mutant restored spontaneous mutation frequencies to wild-type levels. In cross-species studies, H. pylori mutY complemented an Escherichia coli mutY mutant and vice versa. In contrast, the ung and mutY mutants did not show higher frequencies of intergenomic recombination or greater sensitivity to UV-induced DNA damage than the wild type. The H. pylori mutY open reading frame contains an eight-adenine homonucleotide tract; we provide evidence that this is subject to slipped-strand mispairing, leading to frameshifts that eliminate gene function. Our findings indicate that H. pylori possesses phase-variable base excision repair, consistent with a tension between repair and mutation
  145. Kamangar, Farin; Dawsey, Sanford M; Blaser, Martin J; Perez-Perez, Guillermo I; Pietinen, Pirjo; Newschaffer, Craig J; Abnet, Christian C; Albanes, Demetrius; Virtamo, Jarmo; Taylor, Philip R. "Opposing risks of gastric cardia and noncardia gastric adenocarcinomas associated with Helicobacter pylori seropositivity". Journal of the National Cancer Institute. 2006 Oct 18;98(20):1445-1452 (MEDL:17047193 #79194)       

    BACKGROUND: Colonization with Helicobacter pylori is a risk factor for gastric adenocarcinoma, but the magnitude of this association and its relationship to anatomic location of the cancer, duration of follow-up, age at diagnosis, histologic subtype, and H. pylori strain differences are less clear. We conducted a prospective nested case-control study of H. pylori serology to address these questions. METHODS: Case and control subjects were selected from the 29,133 50- to 69-year-old males recruited into the Alpha-Tocopherol, Beta-Carotene Cancer Prevention Study. At baseline, detailed demographic data and a serum sample were collected. From 1985 to 1999, 243 incident cases of gastric adenocarcinoma were diagnosed in cohort members. Serum samples from 234 case subjects (173 with noncardia gastric cancers and 61 with gastric cardia cancers) and 234 age-matched control subjects were assayed for antibodies against H. pylori whole-cell and CagA antigens. We fit conditional logistic regression models to estimate the unadjusted and adjusted odds ratios (ORs) and 95% confidence intervals (CIs) for the association of H. pylori seropositivity, defined as seropositivity to either whole-cell or CagA antigens, with noncardia gastric and gastric cardia cancers. All statistical tests were two-sided. RESULTS: H. pylori seropositivity was strongly associated with the risk of noncardia gastric cancer (adjusted OR = 7.9, 95% CI = 3.0 to 20.9) but was inversely associated with the risk of gastric cardia cancer (adjusted OR = 0.31, 95% CI = 0.11 to 0.89). H. pylori seropositivity rates did not vary statistically significantly by length of follow-up, age at diagnosis, or histologic subtype. A calculation of rates showed that the absolute risks of noncardia gastric and cardia gastric adenocarcinomas in the H. pylori-positive participants of this cohort would be 63 and 12 per 100,000 person-years, respectively, whereas corresponding rates in H. pylori-negative participants would be 8 and 37 per 100,000 person-years, respectively. CONCLUSION: H. pylori is a strong risk factor for noncardia gastric cancer but is inversely associated with the risk of gastric cardia cancer. These findings bolster the hypothesis that decreasing H. pylori prevalence during the past century may have contributed to lower rates of noncardia cancer and higher rates of cardia cancer in Western countries
  146. Kang, Josephine M; Iovine, Nicole M; Blaser, Martin J. "A paradigm for direct stress-induced mutation in prokaryotes". FASEB journal. 2006 Dec;20(14):2476-2485 (MEDL:17142797 #69607)       

    Environmental stresses may lead to selection for hypermutator bacterial cells, which have an increased chance of generating beneficial variants. With stress removal, cost of mutation exceeds the fitness advantage, selecting against hypermutators. Hypermutators arise through several mechanisms, including inactivation of mismatch repair genes (MMR) or induction of error-prone polymerases. Helicobacter pylori may provide an alternative mechanism of stress-induced mutagenesis, since it lacks the MMR genes and error-prone polymerases found in other bacterial species, and possesses an endogenously high mutation frequency. In this study, we expose H. pylori strains to reactive oxygen species and reactive nitrogen species, stressors found in their natural environment. These exposures directly resulted in elevated rates of spontaneous point mutation, deletion between direct repeats, and intergenomic recombination. We demonstrate that these effects are transient and do not involve selection for hypermutator strains. That H. pylori possesses direct repeats in regions where potential gene rearrangements can occur suggests a mechanism for targeted mutation in response to stress that avoids the deleterious fitness costs of fixed hypermutation. These studies provide a new paradigm for adaptation under increased selective pressures that may be present in other prokaryotes
  147. Kang, Josephine; Blaser, Martin J. "Bacterial populations as perfect gases: genomic integrity and diversification tensions in Helicobacter pylori". Nature reviews. Microbiology. 2006 Nov;4(11):826-836 (MEDL:17041630 #69084)       

    Microorganisms that persist in single hosts face particular challenges. Helicobacter pylori, an obligate bacterial parasite of the human stomach, has evolved a lifestyle that features interstrain competition and intraspecies cooperation, both of which involve horizontal gene transfer. Microbial species must maintain genomic integrity, yet H. pylori has evolved a complex nonlinear system for diversification that exists in dynamic tension with the mechanisms for ensuring fidelity. Here, we review these tensions and propose that they create a dynamic pool of genetic variants that is sufficiently genetically diverse to allow H. pylori to occupy all of the potential niches in the stomach
  148. Kang, Josephine; Blaser, Martin J. "UvrD helicase suppresses recombination and DNA damage-induced deletions". Journal of bacteriology. 2006 Aug;188(15):5450-5459 (MEDL:16855234 #67539)       

    UvrD, a highly conserved helicase involved in mismatch repair, nucleotide excision repair (NER), and recombinational repair, plays a critical role in maintaining genomic stability and facilitating DNA lesion repair in many prokaryotic species. In this report, we focus on the UvrD homolog in Helicobacter pylori, a genetically diverse organism that lacks many known DNA repair proteins, including those involved in mismatch repair and recombinational repair, and that is noted for high levels of inter- and intragenomic recombination and mutation. H. pylori contains numerous DNA repeats in its compact genome and inhabits an environment rich in DNA-damaging agents that can lead to increased rearrangements between such repeats. We find that H. pylori UvrD functions to repair DNA damage and limit homologous recombination and DNA damage-induced genomic rearrangements between DNA repeats. Our results suggest that UvrD and other NER pathway proteins play a prominent role in maintaining genome integrity, especially after DNA damage; thus, NER may be especially critical in organisms such as H. pylori that face high-level genotoxic stress in vivo
  149. Kim, Seok-Yong; Lee, Yong-Chan; Kim, Hyong Kyu; Blaser, Martin J. "Helicobacter pylori CagA transfection of gastric epithelial cells induces interleukin-8". Cellular microbiology. 2006 Jan;8(1):97-106 (MEDL:16367869 #79212)       

    To determine the effect of Helicobacter pylori CagA expression on interleukin-8 (IL-8) induction in AGS cells, cagA and five of its fragments from strains 147A and 147C that vary in the 3' repeat region were cloned into the eukaryotic expression plasmid pSP65SRalpha. IL-8, but not RANTES or IL-Ibeta, levels were increased in AGS cells transfected with 147A-cagA and to a greater extent with 147C-cagA, compared with negative controls. The 5' b fragment from the two strains had similar effects, but the 3' d and e fragments from 147C CagA had greater effects than those from 147A-CagA. When the Western CagA-specific sequence (WSS) of 147C-cagA was replaced with East Asian CagA-specific sequence (ESS) and cloned into pSP65SRalpha as an East/West chimera, there was no significant effect on IL-8 production. Use of specific inhibitors indicates that Src kinase activation, and the mitogen-activated protein (MAP) kinase and NF-kappaB pathways are the major intermediates for CagA effects on IL-8 induction, but the p38 MAP kinase pathway has little effect. These results indicate a direct CagA effect on IL-8 induction by gastric epithelial cells, and indicate signal pathway loci that can be targeted for amelioration
  150. Krause-Gruszczynska, M; Rohde, M; Hartig, R; Schmidt, G; Miller, WG; Blaser, MJ; Konig, W; Backert, S. "Role of the small Rho GTPases Racl and Cdc42 in epithelial cell invasion of Campylobacter jejuni 81-176 [Meeting Abstract]". International journal of medical microbiology : IJMM. 2006 SEP;296(2):167-167 (ISI:000241442600337 #70623)    
  151. Lee, I; Kim, J; Ryu, E; Choi, Y; Cheon, J; Lee, Y; Kim, S; Blaser, M. "Deregulation of SHP-2 affecting signal transduction switch by Helicobacter pylori oncoprotein CagA [Meeting Abstract]". Helicobacter. 2006 AUG;11(4):394-395 (ISI:000239005100224 #68676)    
  152. Paulino, Luciana C; Tseng, Chi-Hong; Strober, Bruce E; Blaser, Martin J. "Molecular analysis of fungal microbiota in samples from healthy human skin and psoriatic lesions". Journal of clinical microbiology. 2006 Aug;44(8):2933-2941 (MEDL:16891514 #66657)       

    Psoriasis, a common cutaneous disease of unknown etiology, may be triggered by infections, including those due to fungi. Since the fungal community of human skin is poorly characterized, we aimed to analyze the mycological microbiota in healthy skin and psoriatic lesions. Twenty-five skin samples from five healthy subjects (flexor forearm) and three patients with psoriasis were analyzed using broad-range 18S ribosomal DNA (rDNA) and 5.8S rDNA/internal transcribed spacer 2 (ITS2) Malassezia-specific PCR primers. Broad-range PCR analysis indicated that most organisms resembled Malassezia. Malassezia-specific 5.8S/ITS2 analysis of 1,374 clones identified five species and four unknown phylotypes, potentially representing new species. The species distribution appears largely host specific and conserved in different sites of healthy skin. In three subjects, the Malassezia microbiota composition appeared relatively stable over time. Samples of Malassezia microbiota from healthy skin and psoriatic lesions were similar in one patient but substantially different in two others. These data indicate the predominance of Malassezia organisms in healthy human skin, host-specific variation, stability over time, and as yet, no consistent patterns differentiating psoriatic skin from healthy skin
  153. Perez-Perez, GI; Andersson, M; Olivares, AZ; Gonzalez, EG; Padilla, FB; Torres, J; Blaser, MJ. "Specific geographic genotypes among Helicobacter pylori strains [Meeting Abstract]". Helicobacter. 2006 AUG;11(4):342-342 (ISI:000239005100075 #68671)    
  154. Perez-Perez, GI; Wong, C; Olivares, AZ; Gonzalez, EG; Padilla, FB; Blaser, MJ. "Stability and variability of cagA and its correlation with disease outcome [Meeting Abstract]". Helicobacter. 2006 AUG;11(4):333-333 (ISI:000239005100052 #68670)    
  155. Pride, David T; Wassenaar, Trudy M; Ghose, Chandrabali; Blaser, Martin J. "Evidence of host-virus co-evolution in tetranucleotide usage patterns of bacteriophages and eukaryotic viruses". BMC genomics. 2006;7:8-8 (MEDL:16417644 #79211)       

    BACKGROUND: Virus taxonomy is based on morphologic characteristics, as there are no widely used non-phenotypic measures for comparison among virus families. We examined whether there is phylogenetic signal in virus nucleotide usage patterns that can be used to determine ancestral relationships. The well-studied model of tail morphology in bacteriophage classification was used for comparison with nucleotide usage patterns. Tetranucleotide usage deviation (TUD) patterns were chosen since they have previously been shown to contain phylogenetic signal similar to that of 16S rRNA. RESULTS: We found that bacteriophages have unique TUD patterns, representing genomic signatures that are relatively conserved among those with similar host range. Analysis of TUD-based phylogeny indicates that host influences are important in bacteriophage evolution, and phylogenies containing both phages and their hosts support their co-evolution. TUD-based phylogeny of eukaryotic viruses indicates that they cluster largely based on nucleic acid type and genome size. Similarities between eukaryotic virus phylogenies based on TUD and gene content substantiate the TUD methodology. CONCLUSION: Differences between phenotypic and TUD analysis may provide clues to virus ancestry not previously inferred. As such, TUD analysis provides a complementary approach to morphology-based systems in analysis of virus evolution
  156. Wirth, Hans-Peter; Yang, Manqiao; Sanabria-Valentin, Edgardo; Berg, Douglas E; Dubois, Andre; Blaser, Martin J. "Host Lewis phenotype-dependent Helicobacter pylori Lewis antigen expression in rhesus monkeys". FASEB journal. 2006 Jul;20(9):1534-1536 (MEDL:16720729 #68992)       

    Both human and H. pylori populations are polymorphic for the expression of Lewis antigens. Using an experimental H. pylori challenge of rhesus monkeys of differing Lewis phenotypes, we aimed to determine whether H. pylori populations adapt their Lewis phenotypes to those of their hosts. After inoculation of four monkeys with a mixture of seven strains identified by RAPD-polymerase chain reaction, H. pylori Lewis expression was followed in 86 isolates obtained over 40 wk. Host Lewis(a/b) secretion status was characterized by immunological assays. Fingerprints of the predominating strain (J166) were identical in all four animals after 40 wk, but its Lewis phenotype had substantial variability in individual hosts. At 40 wk, J166 populations from two Lewis(a-b+) animals predominantly expressed Lewis(y). In contrast, J166 populations had switched to a Lewis(x) dominant phenotype in the two Lewis(a+b-) animals; a frame shift in futC, regulating conversion of Lewis(x) to Lewis(y), accounted for the phenotypic switch. The results indicate that individual cells in H. pylori populations can change Lewis phenotypes during long-term colonization of natural hosts to resemble those of their hosts, providing evidence for host selection for bacterial phenotypes
  157. Yu, Lihua; Blaser, Martin; Andrei, Paula I; Pierik, Antonio J; Selmer, Thorsten. "4-Hydroxyphenylacetate decarboxylases: properties of a novel subclass of glycyl radical enzyme systems". Biochemistry. 2006 Aug 8;45(31):9584-9592 (MEDL:16878993 #79209)       

    The 4-hydroxyphenylacetate decarboxylases from Clostridium difficile and Clostridium scatologenes, which catalyze the formation of p-cresol, form a distinct group of glycyl radical enzymes (GREs). Cresol formation provides metabolic toxicity, which allows an active suppression of other microbes and may provide growth advantages for the producers in highly competitive environments. The GRE decarboxylases are characterized by a small subunit, which is not similar to any protein of known function in the databases, and provides unique properties that have not been observed in other GREs. Both decarboxylases are functional hetero-octamers (beta(4)gamma(4)), which contain iron-sulfur centers in addition to the glycyl radical prosthetic group. The small subunit is responsible for metal binding and is also involved in the regulation of the enzymes' oligomeric state and activity, which are triggered by reversible serine phosphorylation of the glycyl radical subunits. Biochemical data suggest that the iron-sulfur centers of the decarboxylases could be involved in the radical dissipation of previously activated enzymes in the absence of substrate. The cognate activating enzymes differ from their Pfl and Nrd counterparts in that up to two iron-sulfur centers, in addition to the characteristic SAM cluster, were found. Biochemical data suggested that these [4Fe-4S] centers are involved in the electron transfer to the SAM cluster but do not directly participate in the reductive cleavage of SAM. These data imply a tight regulation of p-cresol formation, which is necessary in order to avoid detrimental effects of the toxic product on the producers
  158. Bhat, Niranjan; Gaensbauer, James; Peek, Richard M; Bloch, Karen; Tham, Kyi-Toe; Blaser, Martin J; Perez-Perez, Guillermo. "Local and systemic immune and inflammatory responses to Helicobacter pylori strains". Clinical & diagnostic laboratory immunology. 2005 Dec;12(12):1393-1400 (MEDL:16339062 #79197)       

    Colonization with Helicobacter pylori eventuates in varied clinical outcomes, which relate to both bacterial and host factors. Here we examine the relationships between cagA status, serum and gastric juice antibody responses, and gastric inflammation in dyspeptic patients. Serum, gastric juice, and gastric biopsy specimens were obtained from 89 patients undergoing endoscopy. H. pylori colonization and cagA status were determined by histology, culture, and PCR methods, and acute inflammation and chronic inflammation in the gastric mucosa were scored by a single pathologist. Serum and gastric juice antibodies to H. pylori whole-cell and CagA antigens were determined by enzyme-linked immunosorbent assay. Relationships between variables were sequentially analyzed using univariate and multivariate statistical methods. Of the 89 subjects, 62 were colonized by H. pylori. By univariate analyses, levels of serum immunoglobulin G (IgG) and IgA and gastric juice IgA antibodies against whole-cell and CagA antigens each were significantly higher in the H. pylori-positive group than in the H. pylori-negative group (P<0.001). H. pylori and CagA sero-positivities were both significantly associated with enhanced inflammation in gastric antrum and body (P<0.02). The presence of gastric juice antibodies to H. pylori antigens was associated with more severe gastric inflammation. However, in multivariate analyses, only the presence of serum antibodies against CagA and, to a lesser extent, whole-cell antigens remained significantly associated with acute and chronic inflammation in antrum and body (P<0.05). Thus, serum antibody response to CagA correlates with severity of gastric inflammation. Furthermore, given the relationships demonstrated by multivariate analysis, determination of gastric juice antibodies may provide a better representation of serum, rather than secretory, immune response
  159. Blaser, Martin J. "An endangered species in the stomach". Scientific american. 2005 Feb;292(2):38-45 (MEDL:15715390 #48225)       
  160. Blaser, Martin J. "The biology of cag in the Helicobacter pylori-human interaction [Editorial]". Gastroenterology. 2005 May;128(5):1512-1515 (MEDL:15887132 #79218)       
  161. Blaser, Martin J. "Theodore E. Woodward Award: Global warming and the human stomach: microecology follows macroecology". Transactions of the American Clinical & Climatological Association. 2005;116:65-75; discussion 75 (MEDL:16555606 #64204)    

    Just as there have been 20th century changes in our 'macroecology,' including global warming, there have been alterations in our 'microecology,' involving the microbial populations that colonize the human body. Helicobacterpylori, an ancient inhabitant of the human stomach, has been disappearing over the course of the 20th century. As such, by comparing H. pylori+ and H. pylori- persons, the consequences of its colonization can be determined. The presence of H. pylori is associated with increased risk for development of gastric cancer and peptic ulceration, and with decreased risk for gastroesophageal reflux disease (GERD) and its sequelae, including esophageal adenocarcinoma. The disappearance of H. pylori (especially cag+ strains), possibly contributing to the risk of these esophageal diseases, may be an indicator for changing human microecology
  162. Blaser, Martin; Schmid-Hempel, Paul. "Determinants of virulence for the parasite Nosema whitei in its host Tribolium castaneum". Journal of invertabrate pathology. 2005 Jul;89(3):251-257 (MEDL:15963529 #79217)       

    For many parasites, especially those that obligately kill the host for transmission, host age is crucially important to determine success. Here, we have experimentally investigated this relationship with the microsporidian parasite, Nosema whitei, in its host, the Red Flour Beetle, Tribolium castaneum. We find that infection is only possible in young larvae and that spore load at the time of transmission (i.e., host death) correlates with host body size. The data suggested that an infection by N. whitei prolongs the life span of the infected larva and prevents them from pupation. Together, virulence to the host and success for the parasite is mainly determined by the host age at infection. The patterns are consistent with theoretical predictions for obligate killer parasites
  163. Cao, Ping; Lee, Kerry Jo; Blaser, Martin J; Cover, Timothy L. "Analysis of hopQ alleles in East Asian and Western strains of Helicobacter pylori". FEMS microbiology letters. 2005 Oct 1;251(1):37-43 (MEDL:16102915 #79216)       

    Helicobacter pylori hopQ (omp27) alleles exhibit a high level of genetic diversity, and certain hopQ genotypes have been associated with an increased risk for peptic ulcer disease. In this study, we analyzed hopQ alleles in H. pylori strains from East Asia and the United States. Phylogenetic analysis indicated the presence of two highly divergent families of hopQ alleles, without evidence of extensive recombination. Type I hopQ alleles from Western and Asian H. pylori strains were similar, and markedly different from type II hopQ alleles. Analyses of synonymous and non-synonymous nucleotide substitutions suggested that there is a positive selection for HopQ amino acid diversity. Type II hopQ alleles were identified commonly in Western H. pylori strains, but rarely in East Asian strains. Nearly all of the East Asian strains analyzed were cagA-positive and contained type I hopQ alleles. Geographic variation in the genetic characteristics of H. pylori strains may be a factor contributing to geographic variation in gastric cancer incidence
  164. Charap, Mitchell H; Levin, Richard I; Pearlman, R Ellen; Blaser, Martin J. "Internal medicine residency training in the 21st century: aligning requirements with professional needs". American journal of medicine. 2005 Sep;118(9):1042-1046 (MEDL:16164893 #58700)       
  165. Cho, Ilseung; Blaser, Martin J; Francois, Fritz; Mathew, Jomol P; Ye, Xiang Y; Goldberg, Judith D; Bini, Edmund J. "Helicobacter pylori and overweight status in the United States: data from the Third National Health and Nutrition Examination Survey". American journal of epidemiology. 2005 Sep 15;162(6):579-584 (MEDL:16093294 #58658)       

    Obesity is an important public health problem in the United States. Because of its potential effects on gastric leptin homeostasis, Helicobacter pylori may play a role in regulating body weight. The authors' aim in this study was to examine the association between H. pylori colonization and overweight status. Nonpregnant participants in the Third National Health and Nutrition Examination Survey (1988-1994) aged > or = 20 years who had had H. pylori testing performed and body mass index (weight (kg)/height (m2)) measured were studied. Overweight was defined as a body mass index greater than or equal to 25. On the basis of serologic results, the participants were categorized into three H. pylori status groups: H. pylori-positive and cytotoxin-associated gene A (cagA)-positive (H. pylori+ cagA+), H. pylori-positive and cagA-negative (H. pylori+ cagA-), and H. pylori-negative (H. pylori-). Of the 7,003 subjects with complete body mass index and H. pylori data, 2,634 (weighted percentage, 22.9%) were H. pylori+ cagA+, 1,385 (15.1%) were H. pylori+ cagA-, and 2,984 (62.0%) were H. pylori-. The adjusted odds of being overweight were 1.17 (95% confidence interval: 0.98, 1.39; p = 0.075) for the H. pylori+ cagA+ group and 0.99 (95% confidence interval: 0.80, 1.22; p = 0.92) for the H. pylori+ cagA- group in comparison with H. pylori- subjects. Serum leptin levels did not differ significantly between the three H. pylori groups. In this US population-based study, there was no significant association between H. pylori colonization, cagA+ strains of H. pylori, and being overweight
  166. Dominguez-Bello, Maria G; Blaser, Martin J. "Are iron-scavenging parasites protective against malaria? [Comment]". Journal of infectious diseases. 2005 Feb 15;191(4):646-646 (MEDL:15655790 #48226)       
  167. Ghose, C; Perez-Perez, G I; van Doorn, L J; Dominguez-Bello, M G; Blaser, M J. "High Frequency of Gastric Colonization with Multiple Helicobacter pylori Strains in Venezuelan Subjects". Journal of clinical microbiology. 2005 Jun;43(6):2635-2641 (MEDL:15956377 #55866)       

    Multiple Helicobacter pylori strains may colonize an individual host. Using enzyme-linked immunosorbent assay and line probe assay (LiPA) techniques, we analyzed the prevalence of mixed H. pylori colonization in 127 subjects from Venezuela, a country of high H. pylori prevalence, from three regions representing different population groups: the Andes (Merida), where Caucasian mestizos predominate, a major city near the coast (Caracas), where Amerindian-Caucasian-African mestizos predominate, and an Amazonian community (Puerto Ayacucho), where Amerindians predominate and mestizos reflect Amerindian and Caucasian ancestry. Among 121 H. pylori-positive persons, the prevalence of cagA-positive strains varied from 50% (Merida) to 86% (Puerto Ayacucho) by LiPA. Rates of mixed colonization also varied, as assessed by LiPA of the vacA s (mean, 49%) and m (mean, 26%) regions. In total, 55% of the individuals had genotypic evidence of mixed colonization. vacA s1c, a marker of Amerindian (East Asian) origin, was present in all three populations, especially from Puerto Ayacucho (86%). These results demonstrate the high prevalence of mixed colonization and indicate that the H. pylori East Asian vacA genotype has survived in all three populations tested
  168. Iovine, NM; Blaser, MJ. "Antimicrobial resistance in Campylobacter - In reply [Letter]". Emerging infectious diseases. 2005 JUN;11(6):984-984 (ISI:000229307400041 #55777)    
  169. Iovine, NM; Blaser, MJ. "Fluoroquinolone use in food animals - Response [Letter]". Emerging infectious diseases. 2005 NOV;11(11):1790-1790 (ISI:000233076300030 #58902)    
  170. Jones, Marcus B; Jani, Rachana; Ren, Dacheng; Wood, Thomas K; Blaser, Martin J. "Inhibition of Bacillus anthracis growth and virulence-gene expression by inhibitors of quorum-sensing". Journal of infectious diseases. 2005 Jun 1;191(11):1881-1888 (MEDL:15871122 #55981)       

    Density-dependent gene expression, quorum sensing (QS), involves the synthesis and detection of low-molecular-weight molecules known as autoinducers. Inhibitors of bacterial QS systems offer potential treatment of infections with highly virulent or multidrug-resistant agents. We studied the effects on Bacillus anthracis growth and the virulence gene (pagA, lef, and cya) expression of the QS inhibitor (5Z)-4-bromo-5-(bromomethylene)-3-butyl-2(5H)-furanone, which is naturally synthesized by the marine alga Delisea pulchra, as well as a related compound and synthetic derivatives. Growth of B. anthracis Sterne strain was substantially reduced in the presence of each furanone in a dose-dependent manner. When furanones were added to midlog-phase cultures of B. anthracis strains with LacZ reporters in pagA, lef, or cya, growth was inhibited, and expression of these virulence genes was inhibited to a proportionately greater extent. These data suggest that use of QS inhibitors could represent novel therapies for anthrax
  171. Kang, Josephine; Benson, S; Blaser, Martin J. "Role of RuvB and RecG helicases in H-pylori recomnination and repair [Meeting Abstract]". Abstracts of the ... general meeting of the American Society for Microbiology. 2005;105:200-200 (BCI:BCI200800236530 #820092)    
  172. Kang, Josephine; Huang, Shuyan; Blaser, Martin J. "Structural and functional divergence of MutS2 from bacterial MutS1 and eukaryotic MSH4-MSH5 homologs". Journal of bacteriology. 2005 May;187(10):3528-3537 (MEDL:15866941 #55800)       

    MutS homologs, identified in nearly all bacteria and eukaryotes, include the bacterial proteins MutS1 and MutS2 and the eukaryotic MutS homologs 1 to 7, and they often are involved in recognition and repair of mismatched bases and small insertion/deletions, thereby limiting illegitimate recombination and spontaneous mutation. To explore the relationship of MutS2 to other MutS homologs, we examined conserved protein domains. Fundamental differences in structure between MutS2 and other MutS homologs suggest that MutS1 and MutS2 diverged early during evolution, with all eukaryotic homologs arising from a MutS1 ancestor. Data from MutS1 crystal structures, biochemical results from MutS2 analyses, and our phylogenetic studies suggest that MutS2 has functions distinct from other members of the MutS family. A mutS2 mutant was constructed in Helicobacter pylori, which lacks mutS1 and mismatch repair genes mutL and mutH. We show that MutS2 plays no role in mismatch or recombinational repair or deletion between direct DNA repeats. In contrast, MutS2 plays a significant role in limiting intergenomic recombination across a range of donor DNA tested. This phenotypic analysis is consistent with the phylogenetic and biochemical data suggesting that MutS1 and MutS2 have divergent functions
  173. Moss, Steven F; Blaser, Martin J. "Mechanisms of disease: Inflammation and the origins of cancer". Nature clinical practice. Oncology. 2005 Feb;2(2):90-7; quiz 1 p following 113 (MEDL:16264881 #79213)       

    Many common cancers develop as a consequence of years of chronic inflammation. Increasing evidence indicates that the inflammation may result from persistent mucosal or epithelial cell colonization by microorganisms; including hepatitis B virus and hepatitis C virus, which can cause hepatocellular cancer; human papilloma virus subtypes, which cause cervical cancer, and the bacterium Helicobacter pylori, which can cause gastric cancer. At present, the cause of other chronic inflammatory conditions associated with increased cancer risk, such as ulcerative colitis, is obscure. Particular microbial characteristics as well as the type of the inflammatory response contribute to clinical outcomes via influence on epithelial cell and immune responses. Persistent inflammation leads to increased cellular turnover, especially in the epithelium, and provides selection pressure that result in the emergence of cells that are at high risk for malignant transformation. Cytokines, chemokines, free radicals, and growth factors modulate microbial populations that colonize the host. Thus, therapeutic opportunities exist to target the causative microbe, the consequent inflammatory mediator, or epithelial cell responses. Such measures could be of value to reduce cancer risk in inflammation-associated malignancies
  174. Nomura, Abraham M Y; Kolonel, Laurence N; Miki, Kazumasa; Stemmermann, Grant N; Wilkens, Lynne R; Goodman, Marc T; Perez-Perez, Guillermo I; Blaser, Martin J. "Helicobacter pylori, pepsinogen, and gastric adenocarcinoma in Hawaii". Journal of infectious diseases. 2005 Jun 15;191(12):2075-2081 (MEDL:15897993 #64080)       

    BACKGROUND: The objective was to investigate the association of Helicobacter pylori and serum pepsinogen (PG) levels with gastric adenocarcinoma. METHODS: Serum obtained from 299 patients at the time of cancer diagnosis and from 336 population-based control subjects was tested for PG I, PG II, and antibodies to H. pylori and to CagA. RESULTS: Subjects with low PG I levels or low PG I/II ratios were at increased risk for cardia and noncardia gastric cancer, whereas those with H. pylori or CagA seropositivity had an elevated risk for noncardia cancer only. Subjects seropositive for either H. pylori or CagA who had low PG I levels had the highest odds ratio (OR) (9.21 [95% confidence interval {CI}, 4.95-17.13]) for noncardia cancer, compared with subjects with neither factor. Elevated risks were also found among subjects with only 1 factor (OR, 5.40 [95% CI, 2.61-11.20] for low PG I level only; OR, 4.86 [95% CI, 5.90-8.13] for H. pylori or CagA seropositivity only). This pattern persisted when PG I/II ratio replaced PG I level and when CagA seropositivity alone replaced H. pylori immunoglobulin G or CagA seropositivity. CONCLUSIONS: The results suggest that persons with both H. pylori or CagA seropositivity and a low PG I level or PG I/II ratio are highly susceptible to development of noncardia gastric cancer
  175. Pei, Zhiheng; Yang, Liying; Peek, Richard M; Jr Levine, Steven M; Pride, David T; Blaser, Martin J. "Bacterial biota in reflux esophagitis and Barrettos esophagus". World journal of gastroenterology : WJG. 2005 Dec 14;11(46):7277-7283 (MEDL:16437628 #61597)    

    AIM: To identify the bacterial flora in conditions such as Barrettos esophagus and reflux esophagitis to determine if they are similar to normal esophageal flora. METHODS: Using broad-range 16S rDNA PCR, esophageal biopsies were examined from 24 patients [9 with normal esophageal mucosa, 12 with gastroesophageal reflux disease (GERD), and 3 with Barrettos esophagus]. Two separate broad-range PCR reactions were performed for each patient, and the resulting products were cloned. In one patient with Barrettos esophagus, 99 PCR clones were analyzed. RESULTS: Two separate clones were recovered from each patient (total = 48), representing 24 different species, with 14 species homologous to known bacteria, 5 homologous to unidentified bacteria, and 5 were not homologous (<97% identity) to any known bacterial 16S rDNA sequences. Seventeen species were found in the reflux esophagitis patients, 5 in the Barrettos esophagus patients, and 10 in normal esophagus patients. Further analysis concentrating on a single biopsy from an individual with Barrettos esophagus revealed the presence of 21 distinct bacterial species. Members of four phyla were represented, including Bacteroidetes, Firmicutes, Proteobacteria, and Actinobacteria. Microscopic examination of each biopsy demonstrated bacteria in intimate association with the distal esophageal epithelium, suggesting that the presence of these bacteria is not transitory. CONCLUSION: These findings provide evidence for a complex, residential bacterial population in esophageal reflux-related disorders. While much of this biota is present in the normal esophagus, more detailed comparisons may help identify potential disease associations
  176. Perez-Perez, Guillermo Ignacio; Olivares, Asalia Zuni; Foo, F Yeong; Foo, Sun; Neusy, Andre J; Ng, Christopher; Holzman, Robert S; Marmor, Michael; Blaser, Martin J. "Seroprevalence of Helicobacter pylori in New York City populations originating in East Asia". Journal of urban health. 2005 Sep;82(3):510-516 (MEDL:16033932 #58190)       

    Helicobacter pylori prevalence is higher in developing countries than in industrialized countries, and within the latter, higher among immigrants than among nativeborn residents. Using a point-prevalence survey, we sought to identify risk factors for H. pylori seropositivity in US urban East Asian-born populations. At a clinic in New York City, we consecutively enrolled 194 East Asian-born adults, who then responded to a survey and provided a blood sample. Assays were performed to detect IgG antibodies against whole cell (WC) and cytotoxin associated gene A (CagA) antigens of H. pylori. For this group (mean age 50.2+/-14.7 years), the mean period of residence in the United States was 11.9+/-7.7 years. The total H. pylori seroprevalence was 70.1%, with highest (81.4%) in Fujianese immigrants. Multiple logistic regression analysis indicated an independent association of H. pylori seropositivity with Fujianese origin [odds ratios (OR) =2.3, 95% confidence interval (95% CI) =1.05-5.0] and inverse associations with period in the United States (OR per year of residency in the United States =0.95, 95% CI =0.91-0.99) and with a history of dyspepsia (OR for a history of stomach pain =0.52, 95% CI =0.3-1.0). We conclude that H. pylori is highly prevalent among recent East Asian immigrants, especially among Fujianese. The protective effects of history of dyspepsia and duration in the United States suggest that these may be markers for antibiotic therapies.
  177. Pillinger, Michael H; Marjanovic, Nada; Kim, Seok-Yong; Scher, Jose U; Izmirly, Peter; Tolani, Sonia; Dinsell, Victoria; Lee, Yong-Chan; Blaser, Martin J; Abramson, Steven B. "Matrix metalloproteinase secretion by gastric epithelial cells is regulated by E prostaglandins and mitogen-activated protein kinases". Journal of biological chemistry. 2005 Mar 18;280(11):9973-9979 (MEDL:15640153 #48227)       

    Since matrix metalloproteinases (MMP) play roles in inflammatory tissue injury, we asked whether MMP secretion by gastric epithelial cells may contribute to gastric injury in response to signals involved in H. pylori-induced inflammation and/or cyclooxygenase inhibition. TNF-alpha, IL-1beta and epidermal growth factor (EGF) stimulated gastric cell MMP-1 secretion, indicating that MMP-1 secretion occurs in inflammatory as well as non-inflammatory situations. MMP-1 secretion required activation of the mitogen-activated protein kinase (MAPK) Erk, and subsequent protein synthesis, but was downregulated by the alternate MAPK, p38. In contrast, secretion of MMP-13 was stimulated by TNF-alpha/IL-1beta but not EGF, was Erk-independent and mediated by p38. MMP-13 secretion was more rapid (peak 6 h) than MMP-1 (peak = 30 h) and only partly depended on protein synthesis, suggesting initial release of a pre-existing MMP-13 pool. Therefore, MMP-1 and MMP-13 secretion are differentially regulated by MAPKs. MMP-1 secretion was regulated by E prostaglandins (PGEs) in an Erk-dependent manner. PGEs enhanced Erk activation and MMP-1 secretion in response to EGF, but inhibited Erk and MMP-1 when TNF-alpha/IL-1beta were the stimuli, indicating that the effects of PGEs on gastric cell responses are context-dependent. These data show that secretion of MMPs is differentially regulated by MAPKs, and suggest mechanisms through which H pylori infection and/or cyclooxygenase inhibition may induce epithelial cell signaling to contribute to gastric ulcerogenesis
  178. Sivapalasingam, Sumathi; Blaser, Martin J. "Bacterial diarrhea in HIV-infected patients: why Clostridium difficile, and why now? [Editorial]". Clinical infectious diseases. 2005 Dec 1;41(11):1628-1630 (MEDL:16267736 #64405)       
  179. Sjolund, Maria; Tano, Eva; Blaser, Martin J; Andersson, Dan I; Engstrand, Lars. "Persistence of resistant Staphylococcus epidermidis after single course of clarithromycin". Emerging infectious diseases. 2005 Sep;11(9):1389-1393 (MEDL:16229767 #79214)    

    We examined how a common therapy that includes clarithromycin affects normally colonizing Staphylococcus epidermidis. Samples from the nostrils of 5 patients receiving therapy were collected before, immediately after, 1 year after, and 4 years after treatment. From each patient and sample, S. epidermidis strains were isolated and analyzed for clarithromycin susceptibility and presence of the erm(C) gene. We show that macrolide-resistant strains of S. epidermidis were selected during therapy and that the same resistant strain may persist for 4 years, in the absence of further antimicrobial treatment
  180. Takata, Tohru; Ando, Takafumi; Israel, Dawn A; Wassenaar, Trudy M; Blaser, Martin J. "Role of dprA in transformation of Campylobacter jejuni". FEMS microbiology letters. 2005 Nov 1;252(1):161-168 (MEDL:16194595 #79215)       

    The role of a dprA ortholog (Cj0634) in Campylobacter jejuni transformation was phenotypically assessed using two strains. C. jejuni strain 11168 was naturally competent for transformation by chromosomal DNA, while efficiency decreased 100-fold in a Cj0634::aphA mutant, whereas C. jejuni strain 480 was not naturally competent. C. jejuni strain 480 but not 11168 could be electro-transformed by shuttle plasmid pRY111, an effect completely abolished by Cj0634 interruption. Complementation of the Cj0634 mutation in C. jejuni strain 480 in trans with vectors containing the dprA homologs from C. jejuni, Helicobacter pylori, or Haemophilus influenzae, completely (for Cj0634) or partially (H. pylori>H. influenzae) restored electro-transformation. Thus, C. jejuni expresses a DprA ortholog that functionally most closely resembles that of H. pylori and is involved in DNA transformation
  181. Tu, Zheng-Chao; Eisner, William; Kreiswirth, Barry N; Blaser, Martin J. "Genetic divergence of Campylobacter fetus strains of mammal and reptile origins". Journal of clinical microbiology. 2005 Jul;43(7):3334-3340 (MEDL:16000457 #57719)       

    Campylobacter fetus is a gram-negative bacterial pathogen of both humans and animals. Two subspecies have been identified, Campylobacter fetus subsp. fetus and Campylobacter fetus subsp. venerealis, and there are two serotypes, A and B. To further investigate the genetic diversity among C. fetus strains of different origins, subspecies, and serotypes, we performed multiple genetic analyses by utilizing random amplification of polymorphic DNA (RAPD), pulsed-field gel electrophoresis (PFGE), and DNA-DNA hybridization. All 10 primers used for the RAPD analyses can distinguish C. fetus strains of reptile and mammal origin, five can differentiate between C. fetus subsp. fetus and C. fetus subsp. venerealis strains, and four showed differences between type A and type B isolates from mammals. PFGE with SmaI and SalI digestion showed varied genome patterns among different C. fetus strains, but for mammalian C. fetus isolates, genome size was well conserved (mean, 1.52 +/- 0.06 Mb for SmaI and 1.52 +/- 0.05 Mb for SalI). DNA-DNA hybridization demonstrated substantial genomic-homology differences between strains of mammal and reptile origin. In total, these data suggest that C. fetus subsp fetus strains of reptile and mammal origin have genetic divergence more extensive than that between the two subspecies and that between the type A and type B strains. Combining these studies with sequence data, we conclude that there has been substantial genetic divergence between Campylobacter fetus of reptile and mammal origin. Diagnostic tools have been developed to differentiate among C. fetus isolates for taxonomic and epidemiologic uses
  182. Tu, Zheng-Chao; Gaudreau, Christiane; Blaser, Martin J. "Mechanisms Underlying Campylobacter fetus Pathogenesis in Humans: Surface-Layer Protein Variation in Relapsing Infections". Journal of infectious diseases. 2005 Jun 15;191(12):2082-2089 (MEDL:15897994 #55980)       

    Campylobacter fetus causes gastrointestinal and systemic infections in humans. Although relapse is common despite antibiotic treatment, the mechanisms are not well understood. The surface-layer proteins (SLPs) of C. fetus, which are critical in virulence, undergo high-frequency phenotypic switching due to recombination of sap homologues, resulting in antigenic variation. To investigate the mechanisms involved in relapsing C. fetus infections, we compared SLP variation in 4 pairs of C. fetus strains that infect humans; initial and follow-up isolations were performed 20 days to 34 months apart. Of the 4 pairs of strains, 2 had antigenic variation, and another provided evidence for selection for SLP-positive populations. Southern hybridization indicated recombination underlying the SLP variation and up-regulation. The fourth pair had the same SLP antigenic profile and sap homologue hybridization pattern, which is consistent with latency of the original strain in a privileged locus. In total, these findings indicate that relapse may reflect at least 3 differing pathogenetic pathways
  183. Aspholm-Hurtig, Marina; Dailide, Giedrius; Lahmann, Martina; Kalia, Awdhesh; Ilver, Dag; Roche, Niamh; Vikstrom, Susanne; Sjostrom, Rolf; Linden, Sara; Backstrom, Anna; Lundberg, Carina; Arnqvist, Anna; Mahdavi, Jafar; Nilsson, Ulf J; Velapatino, Billie; Gilman, Robert H; Gerhard, Markus; Alarcon, Teresa; Lopez-Brea, Manuel; Nakazawa, Teruko; Fox, James G; Correa, Pelayo; Dominguez-Bello, Maria Gloria; Perez-Perez, Guillermo I; Blaser, Martin J; Normark, Staffan; Carlstedt, Ingemar; Oscarson, Stefan; Teneberg, Susann; Berg, Douglas E; Boren, Thomas. "Functional Adaptation of BabA, the H. pylori ABO Blood Group Antigen Binding Adhesin". Science. 2004 Jul 23;305(5683):519-522 (MEDL:15273394 #43533)       

    Adherence by Helicobacter pylori increases the risk of gastric disease. Here, we report that more than 95% of strains that bind fucosylated blood group antigen bind A, B, and O antigens (generalists), whereas 60% of adherent South American Amerindian strains bind blood group O antigens best (specialists). This specialization coincides with the unique predominance of blood group O in these Amerindians. Strains differed about 1500-fold in binding affinities, and diversifying selection was evident in babA sequences. We propose that cycles of selection for increased and decreased bacterial adherence contribute to babA diversity and that these cycles have led to gradual replacement of generalist binding by specialist binding in blood group O-dominant human populations
  184. Blaser MJ. "You may have this stomach bug and not even know it". Bottom Line/Health. 2004;18(7):7-11 (CINAHL:2005013630 #48032)    

    H. pylori is found in 30% of Americans. New research suggests that its effect on your health may be much more complex than once believed
  185. Blaser, Martin J. "Bacteria and diseases of unknown cause: hemolytic-uremic syndrome [Comment]". Journal of infectious diseases. 2004 Feb 1;189(3):552-555 (MEDL:14745714 #42604)       
  186. Blaser, Martin J; Atherton, John C. "Helicobacter pylori persistence: biology and disease". Journal of clinical investigation. 2004 Feb;113(3):321-333 (MEDL:14755326 #42598)       

    Helicobacter pylori are bacteria that have coevolved with humans to be transmitted from person to person and to persistently colonize the stomach. Their population structure is a model for the ecology of the indigenous microbiota. A well-choreographed equilibrium between bacterial effectors and host responses permits microbial persistence and health of the host but confers risk of serious diseases, including peptic ulceration and gastric neoplasia
  187. Cho, I; Bini, EJ; Francois, F; Blaser, MJ. "Helicobacter pylori seropositivity is not associated with being overweight among persons in the United States: Data from the Third National Health and Nutrition Examination Survey (NHANES III) [Meeting Abstract]". American journal of gastroenterology. 2004 OCT;99(10):S43-S43 (ISI:000224479700128 #49060)    
  188. Cho, I; Bini, EJ; Francois, F; Blaser, MJ. "Lack of association between Helicobacter pylori seropositivity and the metabolic syndrome among persons in the United States: Data from the Third National Health and Nutrition Examination Survey (NHANES III) [Meeting Abstract]". American journal of gastroenterology. 2004 OCT;99(10):S42-S42 (ISI:000224479700124 #49059)    
  189. Francois, F; Bini, EJ; Perez-Perez, GI; Yee, HT; Blaser, MJ. "A three-component clinical model to predict reflux-related histopathology [Meeting Abstract]". Gastroenterology. 2004;126(4):A324-A324 (ISI:000220890201628 #108227)    
  190. Iovine, Nicole M; Blaser, Martin J. "Antibiotics in animal feed and spread of resistant Campylobacter from poultry to humans [Comment]". Emerging infectious diseases. 2004 Jun;10(6):1158-1159 (MEDL:15224671 #43534)    
  191. Iovine, Nicole M; Blaser, Martin J. "Antimicrobial resistance in Campylobacter [Comment]". Emerging infectious diseases. 2004 Jul;10(7):1346-1346 (MEDL:15338553 #44758)    
  192. Kang, Josephine; Gregory, AE; Aras, RA; Blaser, Martin J. "Role of UvrD helicase and DNA damage in Helicobacter pylori transient hypermutation [Meeting Abstract]". Abstracts of the ... general meeting of the American Society for Microbiology. 2004;104:228-228 (BCI:BCI200700324092 #820102)    
  193. Kang, Josephine; Tavakoli, Don; Tschumi, Ariane; Aras, Rahul A; Blaser, Martin J. "Effect of host species on recG phenotypes in Helicobacter pylori and Escherichia coli". Journal of bacteriology. 2004 Nov;186(22):7704-7713 (MEDL:15516585 #47826)       

    Recombination is a fundamental mechanism for the generation of genetic variation. Helicobacter pylori strains have different frequencies of intragenomic recombination, arising from deletions and duplications between DNA repeat sequences, as well as intergenomic recombination, facilitated by their natural competence. We identified a gene, hp1523, that influences recombination frequencies in this highly diverse bacterium and demonstrate its importance in maintaining genomic integrity by limiting recombination events. HP1523 shows homology to RecG, an ATP-dependent helicase that in Escherichia coli allows repair of damaged replication forks to proceed without recourse to potentially mutagenic recombination. Cross-species studies done show that hp1523 can complement E. coli recG mutants in trans to the same extent as E. coli recG can, indicating that hp1523 has recG function. The E. coli recG gene only partially complements the hp1523 mutation in H. pylori. Unlike other recG homologs, hp1523 is not involved in DNA repair in H. pylori, although it has the ability to repair DNA when expressed in E. coli. Therefore, host context appears critical in defining the function of recG. The fact that in E. coli recG phenotypes are not constant in other species indicates the diverse roles for conserved recombination genes in prokaryotic evolution
  194. Pagano, Joseph S; Blaser, Martin; Buendia, Marie-Annick; Damania, Blossom; Khalili, Kamel; Raab-Traub, Nancy; Roizman, Bernard. "Infectious agents and cancer: criteria for a causal relation". Seminars in cancer biology. 2004 Dec;14(6):453-471 (MEDL:15489139 #79219)       

    Infectious agents, mainly viruses, are among the few known causes of cancer and contribute to a variety of malignancies worldwide. The agents and cancers considered here are human papillomaviruses (cervical carcinoma); human polyomaviruses (mesotheliomas, brain tumors); Epstein-Barr virus (B-cell lymphoproliferative diseases and nasopharyngeal carcinoma); Kaposi's Sarcoma Herpesvirus (Kaposi's Sarcoma and primary effusion lymphomas); hepatitis B and hepatitis C viruses (hepatocellular carcinoma); Human T-cell Leukemia Virus-1 (T-cell leukemias); and helicobacter pylori (gastric carcinoma), which account for up to 20% of malignancies around the globe. The criteria most often used in determining causality are consistency of the association, either epidemiologic or on the molecular level, and oncogenicity of the agent in animal models or cell cultures. However use of these generally applied criteria in deciding on causality is selective, and the criteria may be weighted differently. Whereas for most of the tumor viruses the viral genome persists in an integrated or episomal form with a subset of viral genes expressed in the tumor cells, some agents (HBV, HCV, helicobacter) are not inherently oncogenic, but infection leads to transformation of cells by indirect means. For some malignancies the viral agent appears to serve as a cofactor (Burkitt's lymphoma-EBV; mesothelioma - SV(40)). For others the association is inconsistent (Hodgkin's Disease, gastric carcinomas, breast cancer-EBV) and may either define subsets of these malignancies, or the virus may act to modify phenotype of an established tumor, contributing to tumor progression rather than causing the tumor. In these cases and for the human polyomaviruses the association with malignancy is less consistent or still emerging. In contrast despite the potent oncogenic properties of some strains of human adenovirus in tissue culture and animals the virus has not been linked with any human cancers. Finally it is likely that more agents, most likely viruses, both known and unidentified, have yet to be implicated in human cancer. In the meantime study of tumorigenic infectious agents will continue to illuminate molecular oncogenic processes
  195. Pei, Zhiheng; Bini, Edmund J; Yang, Liying; Zhou, Meisheng; Francois, Fritz; Blaser, Martin J. "Bacterial biota in the human distal esophagus". Proceedings of the National Academy of Sciences of the United States of America. 2004 Mar 23;101(12):4250-4255 (MEDL:15016918 #42671)       

    The esophagus, like other luminal organs of the digestive system, provides a potential environment for bacterial colonization, but little is known about the presence of a bacterial biota or its nature. By using broad-range 16S rDNA PCR, biopsies were examined from the normal esophagus of four human adults. The 900 PCR products cloned represented 833 unique sequences belonging to 41 genera, or 95 species-level operational taxonomic units (SLOTU); 59 SLOTU were homologous with culture-defined bacterial species, 34 with 16S rDNA clones, and two were not homologous with any known bacterial 16S rDNA. Members of six phyla, Firmicutes, Bacteroides, Actinobacteria, Proteobacteria, Fusobacteria, and TM7, were represented. A large majority of clones belong to 13 of the 41 genera (783/900, 87%), or 14 SLOTU (574/900, 64%) that were shared by all four persons. Streptococcus (39%), Prevotella (17%), and Veilonella (14%) were most prevalent. The present study identified approximately 56-79% of SLOTU in this bacterial ecosystem. Most SLOTU of esophageal biota are similar or identical to residents of the upstream oral biota, but the major distinction is that a large majority (82%) of the esophageal bacteria are known and cultivable. These findings provide evidence for a complex but conserved bacterial population in the normal distal esophagus
  196. Pillinger, MH; Marjanovic, N; Izmirly, P; Dinsell, V; Tolani, S; Blaser, MJ; Abramson, SB. "Gastric epithelial cell matrix metalloproteinase secretion is stimulated by H. pvlori and inflammatory cytokines, and inhibited by E prostaglandins: Regulation by MAP kinases [Meeting Abstract]". Arthritis & rheumatism. 2004 SEP;50(9):S327-S327 (ISI:000223799000844 #49039)    
  197. Tu, Zheng-Chao; Hui, John; Blaser, Martin J. "Conservation and diversity of sap homologues and their organization among Campylobacter fetus isolates". Infection & immunity. 2004 Mar;72(3):1715-1724 (MEDL:14977980 #42586)       

    Campylobacter fetus surface layer proteins (SLPs), encoded by sapA homologues, are important in virulence. In wild-type C. fetus strain 23D, all eight sapA homologues are located in the 54-kb sap island, and SLP expression reflects the position of a unique sapA promoter in relation to the sapA homologues. The extensive homologies in the sap island include both direct and inverted repeats, which allow DNA rearrangements, deletion, or duplication; these elements confer substantial potential for genomic plasticity. To better understand C. fetus sap island diversity and variation mechanisms, we investigated the organization and distribution of sapA homologues among 18 C. fetus strains of different subspecies, serotypes, and origins. For all type A strains, the boundaries of the sap island were relatively consistent. A 187-bp noncoding DNA insertion near the upstream boundary of the sap island was found in two of three reptile strains studied. The sapA homologue profiles were strain specific, and six new sapA homologues were recognized. Several homologues from reptile strains are remarkably conserved in relation to their corresponding mammalian homologues. In total, the observed differences suggest that the sap island has evolved differing genotypes that are plastic, perhaps enabling colonization of varied niches, in addition to antigenic variation
  198. Tu, Zheng-Chao; Zeitlin, Gary; Gagner, Jean-Pierre; Keo, Thormika; Hanna, Bruce A; Blaser, Martin J. "Campylobacter fetus of Reptile Origin as a Human Pathogen". Journal of clinical microbiology. 2004 Sep;42(9):4405-4407 (MEDL:15365057 #44757)       

    A Campylobacter species was isolated from blood from a febrile patient with precursor T-cell acute lymphoblastic leukemia, and after antibiotic treatment, a similar bacterium was isolated from blood 37 days later. Although phenotypic testing did not definitively identify the organisms, molecular analysis indicated that they were the same strain of Campylobacter fetus subsp. fetus and were of reptile origin
  199. Webb, Glenn F; Blaser, Martin J; Zhu, Huaiping; Ardal, Sten; Wu, Jianhong. "Critical role of nosocomial transmission in the toronto sars outbreak". Mathematical biosciences & engineering : MBE. 2004 Jun;1(1):1-13 (MEDL:20369956 #165593)       

    We develop a compartmental mathematical model to address the role of hospitals in severe acute respiratory syndrome ( SARS ) transmission dynamics, which partially explains the heterogeneity of the epidemic. Comparison of the effects of two major policies, strict hospital infection control procedures and community-wide quarantine measures, implemented in Toronto two weeks into the initial outbreak, shows that their combination is the key to short-term containment and that quarantine is the key to long-term containment.
  200. Wirth, Thierry; Wang, Xiaoyan; Linz, Bodo; Novick, Richard P; Lum, J Koji; Blaser, Martin; Morelli, Giovanna; Falush, Daniel; Achtman, Mark. "Distinguishing human ethnic groups by means of sequences from Helicobacter pylori: lessons from Ladakh". Proceedings of the National Academy of Sciences of the United States of America. 2004 Apr 6;101(14):4746-4751 (MEDL:15051885 #63880)       

    The history of mankind remains one of the most challenging fields of study. However, the emergence of anatomically modern humans has been so recent that only a few genetically informative polymorphisms have accumulated. Here, we show that DNA sequences from Helicobacter pylori, a bacterium that colonizes the stomachs of most humans and is usually transmitted within families, can distinguish between closely related human populations and are superior in this respect to classical human genetic markers. H. pylori from Buddhists and Muslims, the two major ethnic communities in Ladakh (India), differ in their population-genetic structure. Moreover, the prokaryotic diversity is consistent with the Buddhists having arisen from an introgression of Tibetan speakers into an ancient Ladakhi population. H. pylori from Muslims contain a much stronger ancestral Ladakhi component, except for several isolates with an Indo-European signature, probably reflecting genetic flux from the Near East. These signatures in H. pylori sequences are congruent with the recent history of population movements in Ladakh, whereas similar signatures in human microsatellites or mtDNA were only marginally significant. H. pylori sequence analysis has the potential to become an important tool for unraveling short-term genetic changes in human populations
  201. Zabar, S; Kalet, AL; Kachur, EK; Triola, M; Yedidia, M; Blaser, M; Steigbigel, NH; Freeman, R; Lipkin, M. "Practicing bioterrorism-related psychosocial skills with standardized patients". Journal of general internal medicine. 2004 APR;19:194-194 (ISI:000221125800720 #702212)    
  202. Ando, T; Aras, R A; Kusugami, K; Blaser, M J; Wassenaar, T M. "Evolutionary history of hrgA, which replaces the restriction gene hpyIIIR in the hpyIII locus of Helicobacter pylori". Journal of bacteriology. 2003 Jan;185(1):295-301 (MEDL:12486066 #34574)       

    A recently identified Helicobacter pylori gene, hrgA, was previously reported to be present in 70 (33%) of 208 strains examined (T. Ando, T. M. Wassenaar, R. M. Peek, R. A. Aras, A. I. Tschumi, L.-J. Van Doorn, K. Kusugami, and M. J. Blaser, Cancer Res. 62:2385-2389, 2002). Sequence analysis of nine such strains indicated that in each strain hrgA replaced hpyIIIR, which encodes a restriction endonuclease and which, together with the gene for its cognate methyltransferase, constitutes the hpyIII locus. As a consequence of either the hrgA insertion or independent mutations, hpyIIIM function was lost in 11 (5%) of the 208 strains examined, rendering chromosomal DNA sensitive to MboI digestion. The evolutionary history of the locus containing either hpyIII or hrgA was reconstructed. By homologous recombination involving flanking sequences, hrgA and hpyIIIR can replace one another in the hpyIII locus, and there is simultaneous replacement of several flanking genes. These findings, combined with the hpyIM/iceA2 locus discovered previously, suggest that the two most strongly conserved methylase genes of H. pylori, hpyIIIM and hpyIM, are both preceded by alternative genes that compete for presence at their loci
  203. Aras, Rahul A; Fischer, Wolfgang; Perez-Perez, Guillermo I; Crosatti, MariaLuisa; Ando, Takafumi; Haas, Rainer; Blaser, Martin J. "Plasticity of repetitive DNA sequences within a bacterial (Type IV) secretion system component". Journal of experimental medicine. 2003 Nov 3;198(9):1349-1360 (MEDL:14581606 #42650)       

    DNA rearrangement permits bacteria to regulate gene content and expression. In Helicobacter pylori, cagY, which contains an extraordinary number of direct DNA repeats, encodes a surface-exposed subunit of a (type IV) bacterial secretory system. Examining potential DNA rearrangements involving the cagY repeats indicated that recombination events invariably yield in-frame open reading frames, producing alternatively expressed genes. In individual hosts, H. pylori cell populations include strains that produce CagY proteins that differ in size, due to the predicted in-frame deletions or duplications, and elicit minimal or no host antibody recognition. Using repetitive DNA, H. pylori rearrangements in a host-exposed subunit of a conserved bacterial secretion system may permit a novel form of antigenic evasion
  204. Aras, Rahul A; Kang, Josephine; Tschumi, Ariane I; Harasaki, Yasuaki; Blaser, Martin J. "Extensive repetitive DNA facilitates prokaryotic genome plasticity". Proceedings of the National Academy of Sciences of the United States of America. 2003 Nov 11;100(23):13579-13584 (MEDL:14593200 #39007)       

    Prokaryotic genomes are substantially diverse, even when from closely related species, with the resulting phenotypic diversity representing a repertoire of adaptations to specific constraints. Within the microbial population, genome content may not be fixed, as changing selective forces favor particular phenotypes; however, organisms well adapted to particular niches may have evolved mechanisms to facilitate such plasticity. The highly diverse Helicobacter pylori is a model for studying genome plasticity in the colonization of individual hosts. For H. pylori, neither point mutation, nor intergenic recombination requiring the presence of multiple colonizing strains, is sufficient to fully explain the observed diversity. Here we demonstrate that H. pylori has extensive, nonrandomly distributed repetitive chromosomal sequences, and that recombination between identical repeats contributes to the variation within individual hosts. That H. pylori is representative of prokaryotes, especially those with smaller (<2 megabases) genomes, that have similarly extensive direct repeats, suggests that recombination between such direct DNA repeats is a widely conserved mechanism to promote genome diversification
  205. Aras, Rahul A; Lee, Yongchan; Kim, Sung-Kook; Israel, Dawn; Peek, Richard M Jr; Blaser, Martin J. "Natural variation in populations of persistently colonizing bacteria affect human host cell phenotype". Journal of infectious diseases. 2003 Aug 15;188(4):486-496 (MEDL:12898434 #39118)       

    The highly diverse bacterium Helicobacter pylori, which persistently colonizes the human stomach, provides models to study the role of genome plasticity in host adaptation. Within H. pylori populations from 2 colonized individuals, intragenomic recombination between cagA DNA repeat sequences leads to deletion or duplication of tyrosine phosphorylation sites in the CagA protein, which is injected by a type IV secretion system into host cells. Experimental coculture of gastric epithelial cells with the strains containing these naturally occurring CagA phosphorylation site variants induced markedly divergent host cell morphologic responses. Mutants were constructed in which a phosphorylation site was either added or deleted in the expressed CagA protein; coculture studies confirmed that the naturally occurring differences in CagA phosphorylation are responsible for the observed phenotypic variation. These findings indicate that within an individual host, intragenomic recombination between H. pylori repetitive DNA produces strain variants differing in their signals to host cells
  206. Blaser, Martin. Great Teachers - Cancer, Ulcer, and Helicobacter: To Have or to Have Not? [Videocast]. [S.l.] : NIH, 2003. Videocast : 00:57:50 ; Air date: Wednesday, November 12, 2003, 12:00:00 PM.   
  207. Chuman, Yoshiko; Takata, Tohru; Sameshima, Hisako; Takeuchi, Shogo; Takatsuka, Yoshifusa; Makino, Torahiko; Blaser, Martin J; Utsunomiya, Atae. "Campylobacter fetus bacteremia in a patient with adult T cell leukemia [Letter]". Clinical infectious diseases. 2003 Jun 1;36(11):1497-1498 (MEDL:12766848 #43540)       
  208. Engel, Lawrence S; Chow, Wong-Ho; Vaughan, Thomas L; Gammon, Marilie D; Risch, Harvey A; Stanford, Janet L; Schoenberg, Janet B; Mayne, Susan T; Dubrow, Robert; Rotterdam, Heidrun; West, A Brian; Blaser, Martin; Blot, William J; Gail, Mitchell H; Fraumeni, Joseph F Jr. "Population attributable risks of esophageal and gastric cancers". Journal of the National Cancer Institute. 2003 Sep 17;95(18):1404-1413 (MEDL:13130116 #79220)       

    BACKGROUND: Several risk factors have been identified for esophageal adenocarcinoma, gastric cardia adenocarcinoma, esophageal squamous cell carcinoma, and noncardia gastric adenocarcinoma, but no study has comprehensively examined their contributions to the cancer burden in the general population. Herein, we estimate the population attributable risks (PARs) for various risk factors observed in a multicenter population-based case-control study. METHODS: We calculated PARs by using 293 patients with esophageal adenocarcinoma, 261 with gastric cardia adenocarcinoma, 221 with esophageal squamous cell carcinoma, 368 with noncardia gastric adenocarcinoma, and 695 control subjects. We included smoking for all four tumor types and Helicobacter pylori infection for noncardia gastric adenocarcinoma as established causal risk factors as well as several other factors for which causality is under evaluation. RESULTS: Ever smoking, body mass index above the lowest quartile, history of gastroesophageal reflux, and low fruit and vegetable consumption accounted for 39.7% (95% confidence interval [CI] = 25.6% to 55.8%), 41.1% (95% CI = 23.8% to 60.9%), 29.7% (95% CI = 19.5% to 42.3%), and 15.3% (95% CI = 5.8% to 34.6%) of esophageal adenocarcinomas, respectively, with a combined PAR of 78.7% (95% CI = 66.5% to 87.3%). Ever smoking and body mass index above the lowest quartile were responsible for 45.2% (95% CI = 31.3% to 59.9%) and 19.2% (95% CI = 4.9% to 52.0%) of gastric cardia adenocarcinomas, respectively, with a combined PAR of 56.2% (95% CI = 38.1% to 72.8%). Ever smoking, alcohol consumption, and low fruit and vegetable consumption accounted for 56.9% (95% CI = 36.6% to 75.1%), 72.4% (95% CI = 53.3% to 85.8%), and 28.7% (95% CI = 11.1% to 56.5%) of esophageal squamous cell carcinomas, respectively, with a combined PAR of 89.4% (95% CI = 79.1% to 95.0%). Ever smoking, history of gastric ulcers, nitrite intake above the lowest quartile, and H. pylori infection were responsible for 18.3% (95% CI = 6.5% to 41.8%), 9.7% (95% CI = 5.4% to 16.8%), 40.7% (95% CI = 23.4% to 60.7%), and 10.4% (95% CI = 0.3% to 79.6%) of noncardia gastric adenocarcinomas, respectively, with a combined PAR of 59.0% (95% CI = 16.2% to 91.4%). CONCLUSION: In this population, a few known risk factors account for a majority of esophageal and gastric cancers. These results suggest that the incidence of these cancers may be decreased by reducing the prevalence of smoking, gastroesophageal reflux, and being overweight and by increasing the consumption of fruits and vegetables
  209. Falush, Daniel; Wirth, Thierry; Linz, Bodo; Pritchard, Jonathan K; Stephens, Matthew; Kidd, Mark; Blaser, Martin J; Graham, David Y; Vacher, Sylvie; Perez-Perez, Guillermo I; Yamaoka, Yoshio; Megraud, Francis; Otto, Kristina; Reichard, Ulrike; Katzowitsch, Elena; Wang, Xiaoyan; Achtman, Mark; Suerbaum, Sebastian. "Traces of human migrations in Helicobacter pylori populations". Science. 2003 Mar 7;299(5612):1582-1585 (MEDL:12624269 #34570)       

    Helicobacter pylori, a chronic gastric pathogen of human beings, can be divided into seven populations and subpopulations with distinct geographical distributions. These modern populations derive their gene pools from ancestral populations that arose in Africa, Central Asia, and East Asia. Subsequent spread can be attributed to human migratory fluxes such as the prehistoric colonization of Polynesia and the Americas, the neolithic introduction of farming to Europe, the Bantu expansion within Africa, and the slave trade
  210. Francois, F; Bini, EJ; Perez-Perez, GI; Blaser, MJ. "Do GERD symptoms predict Helicobacter pylori colonization? [Meeting Abstract]". Gastroenterology. 2003;124(4):A624-A624 (ISI:000182675903158 #108237)    
  211. Francois, F; Bini, EJ; Perez-Perez, GI; Yee, HT; Blaser, MJ. "Relationship of Helicobacter pylori and strain characteristics to esophageal pathology [Meeting Abstract]". Gastroenterology. 2003;124(4):A55-A55 (ISI:000182675900269 #108235)    
  212. Grogono-Thomas, R; Blaser, M J; Ahmadi, M; Newell, D G. "Role of S-layer protein antigenic diversity in the immune responses of sheep experimentally challenged with Campylobacter fetus subsp. fetus". Infection & immunity. 2003 Jan;71(1):147-154 (MEDL:12496160 #34572)       

    Surface layer proteins (SLPs) are essential for induction of abortion by Campylobacter fetus subsp. fetus in experimentally challenged ewes. These proteins are encoded by multiple sap genes and vary in size and antigenicity. The role of SLP antigenic variation during experimental ovine infection was investigated. Following subcutaneous challenge, the SLPs were highly antigenic, and antibodies were detected in serum, milk, bile, and urine. Fecal anti-SLP antibodies were detected only in animals challenged orally. Ewes challenged with wild-type strain 23D with variable SLPs developed detectable circulating anti-SLP immunoglobulin G (IgG) antibodies by 2 weeks postchallenge. In contrast, ewes challenged with mutants of 23D that had fixed expression of a single SLP developed antibodies within 1 week postchallenge, suggesting that antigenic variation in SLPs may delay the host antibody response. Although not statistically significant, the data from challenge experiments in which vaccinated ewes were used suggested that SLP-expressing vaccines could protect animals from abortion and that this effect was independent of the SLP expressed, indicating involvement of conserved epitopes in the SLP. The conserved 184-amino-acid N-terminal region of the SLP, identified from previously published sequences, was epitope mapped with rabbit anti-SLP antisera by using overlapping synthetic 20-mer peptides. Two putative epitopes were identified at amino acids 81 to 110 and 141 to 160. Amino acids 81 to 100 also bound serum IgG antibodies from experimentally challenged sheep. Conserved antigenic regions of the SLP that induce protective immune responses may enable development of synthetic vaccine candidates for C. fetus subsp. fetus-associated ovine abortion
  213. Jones, Marcus B; Blaser, Martin J. "Detection of a luxS-signaling molecule in Bacillus anthracis". Infection & immunity. 2003 Jul;71(7):3914-3919 (MEDL:12819077 #39188)       

    Quorum-sensing regulation of density-dependent genes has been described for numerous bacterial species. The partially annotated genome sequence of Bacillus anthracis contains an open reading frame (BA5047) predicted to encode an ortholog of luxS, required for synthesis of the quorum-sensing signaling molecule autoinducer-2 (AI-2). To determine whether B. anthracis produces AI-2, the Vibrio harveyi luminescence bioassay was used. Cell-free conditioned media from vaccine (Sterne) strain 34F(2) induced luminescence in V. harveyi reporter strain BB170, indicating its production of AI-2. Cloned BA5047, expressed in Escherichia coli DH5 alpha cells, restored AI-2 activity to these cells. To evaluate whether BA5047 is essential for AI-2 synthesis, it was deleted through allelic exchange with marker rescue; the resulting mutant had no functional luxS activity and had reduced growth in vitro. In the wild-type strain, AI-2 activity was greatest during the exponential phase of growth. In total, these data indicate that BA5047 is a functional luxS ortholog in B. anthracis necessary for growth-phase-specific AI-2 expression. Thus, B. anthracis may utilize extracellular signaling molecules to regulate density-dependent gene expression
  214. Kang, Josephine; Aras, RA; Blaser, Martin J. "The role of Helicobacter pylori mutS2 in genome plasticity [Meeting Abstract]". Abstracts of the ... general meeting of the American Society for Microbiology. 2003;103:?-? (BCI:BCI200300520519 #820112)    

    Helicobacter pylori is noted for its high level of genetic diversity. A naturally competent organism, H. pylori is capable of genomic diversification through intergenomic and intragenomic recombination, and spontaneous mutation. DNA repair genes, such as mutS, have been shown to influence the generation of diversity by modulating mutation rates. In E. coli, mutS mutants have rates of spontaneous mutation and intragenomic recombination elevated by 1000- and 100-fold, respectively. Sequences of H. pylori strains 26695 and J99 do not show a mutS homolog, but show a related gene, mutS2, which is well-conserved amongst bacterial species. To examine the role of mutS2 in H. pylori, mutant JP26 mutS2::aphA was created by inserting a kanamycin resistance (aphA) cassette into mutS2 of strain JP26. The role of mutS2 in intergenomic recombination was assessed by transformation with an 800 bp PCR product that confers streptomycin resistance; intragenomic recombination was assessed by quantifying deletion of a 869 bp cassette flanked by direct DNA repeats; and spontaneous mutation was assessed by determining rifampin resistance. Intergenomic recombination frequencies of JP26 mutS::aphA (4.3X10-6+-2.X10-6) were consistently higher (11.2-fold) and significantly (p=0.002) different from transformation frequencies of wild-type JP26 (4.1X10-7+-2.1X10-7). Intragenomic recombination frequencies of JP26 mutS2::aphA and wild-type JP26 were not significantly (p>0.05) different. Spontaneous mutation frequencies of JP26 mutS2::aphA (5.0X10-7+-6.4X10-7) were consistently higher (25-fold) and significantly (p=0.03) different from wild-type JP26 (2.0X10-8+-2.2X10-8). Our findings indicate that mutS2 may play a role in intergenomic recombination and mismatch repair, but not intragenomic recombination. Thus, mutS2 may function in H. pylori as a DNA repair gene and influence its rate of genomic diversification
  215. Kato, Seiichi; Okamoto, Hiroaki; Nishino, Yoshikazu; Oyake, Yasuo; Nakazato, Yutaka; Okuda, Masumi; Fujisawa, Takuji; Iinuma, Kazuie; Blaser, Martin J. "Helicobacter pylori and TT virus prevalence in Japanese children". Journal of gastroenterology. 2003;38(12):1126-1130 (MEDL:14714248 #43536)       

    BACKGROUND: The major transmission route of Helicobacter pylori, oral-oral or fecal-oral, remains to be established. TT virus (TTV), a recently discovered microbe that is prevalent in healthy persons, is believed to be mainly transmitted by nonparenteral routes. The purpose of this study was to test the hypothesis that these two microorganisms have a common mode of transmission. METHODS: We investigated the seroprevalence of H. pylori and TTV in a cross-sectional study of 454 healthy Japanese children from birth to age 15 years, living in five different geographic areas. Determination of H. pylori status was based on the presence of specific serum IgG and IgA antibodies, determined using enzyme immunoassays. TTV DNA was detected and the titer was determined using semiquantitative polymerase chain reaction with heminested primers. RESULTS: The overall prevalences of H. pylori and TTV were 12.2% and 21.6%, respectively. An age-related increase of prevalence was shown for H. pylori ( P < 0.001), but not for TTV ( P = 0.23). Titers of TTV DNA significantly decreased with age (P = 0.02). There were significant geographic differences in TTV prevalence ( P < 0.001), but not in H. pylori seroprevalence (P = 0.33). There was no true correlation between the prevalence of these two organisms (Phi coefficient = -0.02 and P = 0.66). CONCLUSIONS: Although Japanese children frequently acquire both H. pylori and TTV, especially in early childhood, their acquisition appears to be independent
  216. Leonard, Edward E 2nd; Takata, Tohru; Blaser, Martin J; Falkow, Stanley; Tompkins, Lucy S; Gaynor, Erin C. "Use of an open-reading frame-specific Campylobacter jejuni DNA microarray as a new genotyping tool for studying epidemiologically related isolates". Journal of infectious diseases. 2003 Feb 15;187(4):691-694 (MEDL:12599089 #43541)       

    Findings from use of an open-reading frame-specific Campylobacter jejuni DNA microarray to investigate genetic diversity among clinical isolates associated with 5 independent clusters of infection were compared with data from random amplified polymeric DNA (RAPD) and Penner serotyping analyses. The DNA microarray provides a highly specific epidemiological typing tool for analysis of C. jejuni isolates and reveals both divergent and highly conserved gene classes among isolates
  217. McGowan, Catherine C; Necheva, Antoaneta S; Forsyth, Mark H; Cover, Timothy L; Blaser, Martin J. "Promoter analysis of Helicobacter pylori genes with enhanced expression at low pH". Molecular microbiology. 2003 Jun;48(5):1225-1239 (MEDL:12787351 #43539)       

    To identify Helicobacter pylori genes with expression that is enhanced under low pH conditions, we used subtractive hybridization methodology. We identified 28 acid-induced genes, of which 18 have known or putative functions. Six pairs of genes were co-transcribed. Primer extension analysis identified single or multiple transcriptional start points (tsp) for 14 of the 22 loci. Sequence analysis of the -10 regions upstream of the tsps revealed consensus motifs for multiple RNA polymerase sigma factors present in H. pylori (sigma80, sigma54 and sigma28). No sequences resembling the -35 Escherichia coli consensus sequence (TTGACA) were present upstream of any of the genes. Both increased gene transcription and decreased mRNA decay contribute to the observed increase in H. pylori transcript abundance at acid pH. These studies document the complex response of H. pylori to environmental pH changes, and provide insight into mechanisms used for intragastric survival
  218. Perez-Perez, Guillermo I; Sack, R Bradley; Reid, Raymond; Santosham, Mathuram; Croll, Janne; Blaser, Martin J. "Transient and persistent Helicobacter pylori colonization in Native American children". Journal of clinical microbiology. 2003 Jun;41(6):2401-2407 (MEDL:12791856 #39203)       

    Helicobacter pylori is chiefly acquired in childhood, but the exact timing of acquisition is not well understood. The main goal of this study was to assess H. pylori acquisition in a pediatric population. We studied two cohorts of Native American children: a birth cohort of 50 children and 58 older children (mean age, 53 months). We measured serum immunoglobulin G (IgG), IgM, and IgA antibodies to H. pylori whole-cell antigen and IgG antibodies to CagA. Among 44 birth cohort children monitored for more than 12 months, 24 (54.5%) had seroconversions, 7 (15.9%) were transient, and 17 (38.6%) were persistent. Among the older children, 49 (84.5%) of the 58 children were monitored for 1 year; 34 (69.4%) had H. pylori antibodies at study entry. During the next year, 7 (20.6%) children seroreverted, and of 15 initially negative children, 5 (33.3%) seroconverted. In both groups, evaluation of CagA antibodies increased the sensitivity of H. pylori detection. Serum pepsinogen I (PGI) levels in H. pylori-negative children rose significantly until age 6 months and remained constant for the next 19 months. At the time of H. pylori seroconversion, PGI peaked to levels significantly higher than in the never-seroconverted (P = 0.02) and the pre-seroconverted (P = 0.03) children, but then declined to levels paralleling those of H. pylori-negative children. Thus, H. pylori acquisition, accompanied by a transient PGI increase, was frequent in this population, especially in the second and third years of life, but often was brief
  219. Pride, David T; Meinersmann, Richard J; Wassenaar, Trudy M; Blaser, Martin J. "Evolutionary implications of microbial genome tetranucleotide frequency biases". Genome research. 2003 Feb;13(2):145-158 (MEDL:12566393 #34571)       

    We compared nucleotide usage pattern conservation for related prokaryotes by examining the representation of DNA tetranucleotide combinations in 27 representative microbial genomes. For each of the organisms studied, tetranucleotide usage departures from expectations (TUD) were shared between related organisms using both Markov chain analysis and a zero-order Markov method. Individual strains, multiple chromosomes, plasmids, and bacteriophages share TUDs within a species. TUDs varied between coding and noncoding DNA. Grouping prokaryotes based on TUD profiles resulted in relationships with important differences from those based on 16S rRNA phylogenies, which may reflect unequal rates of evolution of nucleotide usage patterns following divergence of particular organisms from a common ancestor. By both symmetrical tree distance and likelihood analysis, phylogenetic trees based on TUD profiles demonstrate a level of congruence with 16S rRNA trees similar to that of both RpoA and RecA trees. Congruence of these trees indicates that there exists phylogenetic signal in TUD patterns, most prominent in coding region DNA. Because relationships demonstrated in TUD-based analyses utilize whole genomes, they should be considered complementary to phylogenies based on single genetic elements, such as 16S rRNA
  220. Sjolund, Maria; Wreiber, Karin; Andersson, Dan I; Blaser, Martin J; Engstrand, Lars. "Long-term persistence of resistant Enterococcus species after antibiotics to eradicate Helicobacter pylori". Annals of internal medicine. 2003 Sep 16;139(6):483-487 (MEDL:13679325 #43537)    

    BACKGROUND: Antibiotic treatment selects for resistance not only in the pathogen to which it is directed but also in the indigenous microflora. OBJECTIVE: To determine whether a widely used regimen (clarithromycin, metronidazole, and omeprazole) for Helicobacter pylori eradication affects resistance development in enterococci. DESIGN: Cohort study. SETTING: Endoscopy units at 3 community hospitals in Sweden. PATIENTS: 5 consecutive dyspeptic patients who were colonized with H. pylori, had endoscopy-confirmed duodenal ulcer, and received antibiotic treatment, and 5 consecutive controls with dyspepsia but no ulcer who did not receive treatment. MEASUREMENTS: Fecal samples were obtained from patients and controls before, immediately after, 1 year after, and 3 years after treatment. From each patient and sample, enterococci were isolated and analyzed for DNA fingerprint, clarithromycin susceptibility, and presence of the erm(B) gene. RESULTS: In treated patients, all enterococci isolated immediately after treatment showed high-level clarithromycin resistance due to erm(B). In 3 patients, resistant enterococci persisted for 1 to 3 years after treatment. No resistance developed among controls. CONCLUSION: A common H. pylori treatment selects for highly resistant enterococci that can persist for at least 3 years without further selection
  221. Stolzenberg-Solomon, Rachael Z; Dodd, Kevin W; Blaser, Martin J; Virtamo, Jarmo; Taylor, Philip R; Albanes, Demetrius. "Tooth loss, pancreatic cancer, and Helicobacter pylori". American journal of clinical nutrition. 2003 Jul;78(1):176-181 (MEDL:12816788 #43538)    

    BACKGROUND: Poor dental health has been associated with increased risks of oral, esophageal, and gastric cancer and may also be associated with pancreatic cancer. In addition, Helicobacter pylori has been found in dental plaque and has been associated with periodontal disease and pancreatic cancer. OBJECTIVE: The objective was to investigate prospectively the relation between dentition history and pancreatic cancer in the Alpha-Tocopherol, Beta-Carotene Cancer Prevention Study cohort in Finland and the association between dentition history and H. pylori seropositivity in a cross-sectional sample of subjects without cancer (n = 475) from the same cohort. DESIGN: Of the 29,104 male smokers aged 50-69 y in the cohort for whom there were complete data, 174 developed pancreatic cancer from 1985 to 1997. Cox proportional hazard models were used to estimate age-, smoking-, education-, urban living-, and height-adjusted hazard ratios and 95% CIs for pancreatic cancer, and logistic regression models were used to estimate age- and education-adjusted odds ratios for H. pylori carriage. RESULTS: Tooth loss was positively associated with pancreatic cancer (edentulous compared with missing 0-10 teeth: hazard ratio = 1.63; 95% CI: 1.09, 2.46; P for trend = 0.02) but was not significantly associated with H. pylori seropositivity (edentulous compared with missing 0-10 teeth: odds ratio = 1.30; 95% CI: 0.73, 2.32; P for trend = 0.37). CONCLUSION: Additional studies are needed to evaluate the association between tooth loss and pancreatic cancer, as well as cancers at other gastrointestinal sites, particularly with respect to possible biological mechanisms
  222. Triola, Marc M; Blaser, Martin J. "An email alert system for internal medicine physicians". Proceedings (AMIA Annual Symposium). 2003;189(3):1035-1035 (MEDL:14728538 #43535)    

    This study evaluated the effectiveness of an email-based alerting system for internal medicine house staff and faculty in geographically dispersed locales. Responses to a test alert email message were used to quantify the rapidity by which physicians read the message, and to define subgroups in which this communication modality proved most successful. The results of this study are being used to improve our preparedness for emergencies
  223. Tu, Zheng-Chao; Wassenaar, Trudy M; Thompson, Stuart A; Blaser, Martin J. "Structure and genotypic plasticity of the Campylobacter fetus sap locus". Molecular microbiology. 2003 May;48(3):685-698 (MEDL:12694614 #34569)       

    The Campylobacter fetus surface layer proteins (SLPs), encoded by five to nine sapA homologues, are major virulence factors. To characterize the sapA homologues further, a 65.9 kb C. fetus genomic region encompassing the sap locus from wild-type strain 23D was completely sequenced and analysed; 44 predicted open reading frames (ORFs) were recognized. The 53.8 kb sap locus contained eight complete and one partial sapA homologues, varying from 2769 to 3879 bp, sharing conserved 553-2622 bp 5' regions, with partial sharing of 5' and 3' non-coding regions. All eight sapA homologues were expressed in Escherichia coli as antigenic proteins and reattached to the surface of SLP- strain 23B, indicating their conserved function. Analysis of the sap homologues indicated three phylogenetic groups. Promoter-specific polymerase chain reactions (PCRs) and sapA homologue-specific reverse transcription (RT)-PCRs showed that the unique sapA promoter can potentially express all eight sapA homologues. Reciprocal DNA recombination based on the 5' conserved regions can involve each of the eight sapA homologues, with frequencies from 10(-1) to 10(-3). Intragenic recombination between sapA7 and sapAp8, mediated by their conserved regions with a 10(-1)-10(-2) frequency, allows the formation of new sap homologues. As divergent SLP C-termini possess multiple antigenic sites, their reciprocal recombination behind the unique sap promoter leads to continuing antigenic variation
  224. Ando, T; Peek, R M; Pride, D; Levine, S M; Takata, T; Lee, Y-C; Kusugami, K; van der Ende, A; Kuipers, E J; Kusters, J G; Blaser, M J. "Polymorphisms of Helicobacter pylori HP0638 reflect geographic origin and correlate with cagA status". Journal of clinical microbiology. 2002 Jan;40(1):239-246 (MEDL:11773122 #39735)       

    Since the associations between Helicobacter pylori genotype and disease differ in Asia and the West, we investigated the correlation between HP0638, encoding an outer membrane protein, and potential markers of virulence (cagA, vacA, and iceA). For 109 strains from nine countries, the status of cagA, vacA, and iceA was determined by PCR and/or a line probe assay. We also studied 18 strains from 8 patients (parents and 6 daughters) from a Dutch family and paired strains collected on average 8 years apart from 11 patients. When the HP0638 signal sequences were amplified by PCR and DNA sequence determinations were performed, 89 (96%) of 93 cagA-positive strains had HP0638 in frame, versus none (0%) of 16 cagA-negative strains (P < 0.001). Among strains in which HP0638 was in frame, a six-CT dinucleotide repeat pattern was dominant in Western countries (23 of 33 strains [70%]), while a pattern of three CT repeats with another CT after four T's (3 + 1-CT-repeat pattern) was dominant in East Asia (31 of 46 strains [67%]); however, specific CT repeat patterns did not correlate with clinical outcome. HP0638 phylogenetic trees also showed geographic characters. The HP0638 frame status and CT dinucleotide repeat patterns were identical for 9 of 11 pairs of strains obtained on average 8 years apart from individuals and the 15 strains obtained from the mother and all six daughters. Thus, HP0638 frame status and cagA status are strongly correlated. The CT dinucleotide repeat pattern in the putative HP0638 signal sequence has geographic characters and appears stable in particular patients and families over a period of years. Analysis of HP0638 CT polymorphisms may serve as a new typing system to discriminate H. pylori isolates for epidemiological purposes
  225. Ando, Takafumi; Peek, Richard M Jr; Lee, Yong-Chan; Krishna, Uma; Kusugami, Kazuo; Blaser, Martin J. "Host cell responses to genotypically similar Helicobacter pylori isolates from United States and Japan". Clinical & diagnostic laboratory immunology. 2002 Jan;9(1):167-175 (MEDL:11777849 #39731)       

    Associations of Helicobacter pylori genotypes with disease differ between Western countries and Asia. Therefore, we directly compared histopathological and in vitro responses to clinical isolates with similar genotypes. Sixty-three cagA(+) vacAs1/m1 H. pylori isolates (United States, n = 24; Japan, n = 39) and eight cagA-negative vacAs2/m2 strains were incubated with AGS cells, and supernatants were assayed for interleukin-8 (IL-8) and for DNA fragmentation. CagA tyrosine phosphorylation in AGS cells and the sequence of the putative HP0638 (oipA) signal sequence region were determined for 22 representative strains. HP0638 and/or cag island mutant strains were created and examined in IL-8 and CagA tyrosine phosphorylation assays. Levels of IL-8 induction and DNA fragmentation were similar in the U.S. and Japanese cagA(+) vacAs1/m1 isolates. All 10 of the isolates with the highest IL-8 induction and 8 of the 10 isolates with the lowest IL-8 induction had an in-frame oipA open reading frame, and all 10 of the isolates with the highest IL-8 induction and 7 of the 10 isolates with the lowest IL-8 induction induced CagA tyrosine phosphorylation in AGS cells. Eight isolates from gastric ulcer patients induced significantly more apoptosis in vitro, and more severe gastritis and atrophy in vivo, than other Japanese isolates. Disruption of HP0638 did not affect IL-8 induction or CagA tyrosine phosphorylation. Thus, H. pylori cagA(+) vacAs1/m1 isolates from the United States and Japan induce similar IL-8 and apoptosis levels. Inactivation of HP0638 does not alter epithelial responses mediated by the cag island in vitro. Assessment of apoptosis in vitro identified a group of H. pylori isolates that induce more severe gastric inflammation and atrophy
  226. Ando, Takafumi; Wassenaar, Trudy M; Peek, Richard M Jr; Aras, Rahul A; Tschumi, Ariane I; van Doorn, Leen-Jan; Kusugami, Kazuo; Blaser, Martin J. "A Helicobacter pylori restriction endonuclease-replacing gene, hrgA, is associated with gastric cancer in Asian strains". Cancer research. 2002 Apr 15;62(8):2385-2389 (MEDL:11956101 #39674)    

    The sensitivity of Helicobacter pylori chromosomal DNA to MboI digestion was investigated in 208 strains from several continents. Only 11 (5%) of strains were sensitive to MboI, and it was hypothesized that HpyIII, a type II restriction/modification enzyme with sequence homology to MboI, mediated the protection. This was confirmed by PCR analysis of the gene locus of hpyIII, normally composed of hpyIIIR and hpyIIIM. In all but one strain sensitive to MboI, no PCR product of hpyIIIR was obtained. In contrast, all strains yielded a product for hpyIIIM, independent of MboI phenotype. Further examination of the hpyIII locus in strains lacking a hpyIIIR PCR product identified a novel gene, hrgA, upstream of hpyIIIM. All 208 strains examined had either hpyIIIR or hrgA, but not both, upstream of hpyIIIM. Although hrgA has homology with a Campylobacter jejuni gene (Cj1602), its function is not known. In Western countries, hrgA was more prevalent (53%) than in Asia (25%; P < 0.0001, chi(2)). In Asia, hrgA was more prevalent among gastric cancer patients (18 of 43; 42%) than among noncancer patients (16 of 95; 17%; P = 0.001, chi(2)). All 143 Asian strains tested were cagA(+), but among Western strains, hrgA was more prevalent in cagA(+) strains (26 of 42; 62%) than in cagA(-) strains (9 of 23; 39%; P = 0.04, chi(2)). In coculture with epithelial cells, hpyIIIR and hrgA strains did not show any significant differences in interleukin-8 induction and apoptosis. Although a direct function for hrgA in virulence could not be demonstrated, our data indicate that hrgA is a strain-specific gene that might be associated with gastric cancer among H. pylori isolates from Asian patients
  227. Aras, Rahul A; Small, Aaron J; Ando, Takafumi; Blaser, Martin J. "Helicobacter pylori interstrain restriction-modification diversity prevents genome subversion by chromosomal DNA from competing strains". Nucleic acids research. 2002 Dec 15;30(24):5391-5397 (MEDL:12490707 #34573)       

    Helicobacter pylori, bacteria that colonize the human gastric mucosa, possess a large number of genes for restriction-modification (R-M) systems, and essentially, every strain possesses a unique complement of functional and partial R-M systems. Nearly half of the H.pylori strains studied possess an active type IIs R-M system, HpyII, with the recognition sequence GAAGA. Recombination between direct repeats that flank the R-M cassette allows for its deletion whereas strains lacking hpyIIRM can acquire this cassette through natural transformation. We asked whether strains lacking HpyII R-M activity can acquire an active hpyIIRM cassette [containing a 1.4 kb kanamycin resistance (aphA) marker], whether such acquisition is DNase sensitive or resistant and whether restriction barriers limit acquisition of chromosomal DNA. Our results indicate that natural transformation and conjugation-like mechanisms may contribute to the transfer of large (4.8 kb) insertions of chromosomal DNA between H.pylori strains, that inactive or partial R-M systems can be reactivated upon recombination with a functional allele, consistent with their being contingency genes, and that H.pylori R-M diversity limits acquisition of chromosomal DNA fragments of >/=1 kb
  228. Beard, Albertine S; Blaser, Martin J. "The ecology of height: the effect of microbial transmission on human height". Perspectives in biology & medicine. 2002 Fall;45(4):475-498 (MEDL:12388882 #34580)       

    The height that adult humans achieve results from a complex interplay between genetic endowment and environmental exposures during development. We hypothesize that exposure to microbes--both exogenous pathogens and endogenous biota--are critical environmental determinants of the expression of human height in a community. Both experimental studies and historical changes in height in relation to presumed microbial transmission support this hypothesis
  229. Blaser, Martin J. Infections of the gastrointestinal tract. Philadelphia PA : Lippincott Williams & Wilkins, 2002. xvi, 1319 p. ; 29cm.   2nd ed    
  230. Blaser, Martin J. "Polymorphic bacteria persisting in polymorphic hosts: assessing Helicobacter pylori-related risks for gastric cancer [Comment]". Journal of the National Cancer Institute. 2002 Nov 20;94(22):1662-1663 (MEDL:12441315 #34576)    
  231. Blaser, Martin J. "The genetic gymnastics of our indigenous microbes". New England journal of medicine. 2002 Jun 27;346(26):2083-2085 (MEDL:12087147 #34585)       
  232. Blaser, Martin J; Saito, Daizo. "Trends in reported adenocarcinomas of the oesophagus and gastric cardia in Japan". European journal of gastroenterology & hepatology. 2002 Feb;14(2):107-113 (MEDL:11981333 #43544)       

    Adenocarcinomas involving the oesophagus and gastric cardia are becoming more common in Western countries, but data from Japan are limited. We sought to determine whether the frequency of these cancers in Japan has increased in recent decades. Review of national cancer mortality data, national registries of oesophageal and gastric cancer cases, and records from two large cancer centres for various time periods between 1950 and 1998 did not show increased reporting of oesophageal adenocarcinomas. In contrast, both national and cancer centre data indicate an absolute increase in the number of gastric cancers involving the C-area (proximal third of the stomach). From a national registry of resected primary gastric cancer cases, those arising in the C-area as a proportion of all tumours rose by 41.8% between 1963 (12.2% of all registered cases) and 1990 (17.3%). Analysis of true cardia (<2 cm distal to oesophagus-cardia junction) early cancers from the two cancer centres showed significant increases in both absolute number and in proportion to other gastric cancers over a 36-year period. These data suggest that the frequency of cardia cancers is increasing in Japan. Lack of a parallel increase in oesophageal adenocarcinomas could be due to misclassification artefacts and/or coding preferences for gastro-oesophageal junction tumours
  233. Drake, Wonder Puryear; Pei, Zhiheng; Pride, David T; Collins, Robert D; Cover, Timothy L; Blaser, Martin J. "Molecular analysis of sarcoidosis tissues for mycobacterium species DNA". Emerging infectious diseases. 2002 Nov;8(11):1334-1341 (MEDL:12453366 #34575)    

    We performed polymerase chain reaction analysis, for Mycobacterium species 16S rRNA, rpoB, and IS6110 sequences, on 25 tissue specimens from patients with sarcoidosis and on 25 control tissue specimens consisting of mediastinal or cervical lymph nodes and lung biopsies. Mycobacterium species 16S rRNA sequences were amplified from 12 (48%) rpoB sequences and from 6 (24%) of the sarcoidosis specimens. In total, 16S rRNA or rpoB sequences were amplified from 15 sarcoidosis specimens (60%) but were not detected in any of the control tissues (p=0.00002, chi square). In three specimens, the sequences resembled Mycobacterium species other than M. tuberculosis. All specimens with sequences consistent with M. tuberculosis were negative for IS6110. We provide evidence that one of a variety of Mycobacterium species, especially organisms resembling M. tuberculosis, is found in most patients with sarcoidosis
  234. Freedman, Abigail; Afonja, Olubunmi; Chang, Mary Wu; Mostashari, Farzad; Blaser, Martin; Perez-Perez, Guillermo; Lazarus, Herb; Schacht, Robert; Guttenberg, Jane; Traister, Michael; Borkowsky, William. "Cutaneous anthrax associated with microangiopathic hemolytic anemia and coagulopathy in a 7-month-old infant". JAMA. 2002 Feb 20;287(7):869-874 (MEDL:11851579 #26017)       

    A 7-month-old infant with cutaneous anthrax developed severe systemic illness despite early treatment with antibiotics. The infant displayed severe microangiopathic hemolytic anemia with renal involvement, coagulopathy, and hyponatremia. These findings are unusual with cutaneous anthrax, but have been described in illness resulting from spider toxin and may delay correct diagnosis. The systemic manifestations of the disease persisted for nearly a month despite corticosteroid therapy, but resolved
  235. Ghose, Chandrabali; Perez-Perez, Guillermo I; Dominguez-Bello, Maria-Gloria; Pride, David T; Bravi, Claudio M; Blaser, Martin J. "East Asian genotypes of Helicobacter pylori strains in Amerindians provide evidence for its ancient human carriage". Proceedings of the National Academy of Sciences of the United States of America. 2002 Nov 12;99(23):15107-15111 (MEDL:12417749 #34577)       

    Phylogenies of indigenous microbes have been used as surrogates for the origins of the hosts that carry them. Conversely, polymorphisms may be used to date the spread of a microbial species when information about their host populations is available. Therefore, we examined polymorphisms in Helicobacter pylori, which persistently colonize the human stomach, to test the hypothesis that they have been ancient inhabitants of humans. Three H. pylori loci that previously have been shown to have phylogeographic affinity have been analyzed for two populations with different ethnic origins from Venezuela. In a group of Amerindian subjects from Amazonia, East Asian H. pylori genotypes were present for each of the loci examined but were absent in a mestizo population from Caracas. These findings provide evidence that H. pylori has been present in humans at least since ancestors of Amerindians migrated from Asia more than 11,000 years ago
  236. Groves, Frank D; Perez-Perez, Guillermo; Zhang, Lian; You, Wei-cheng; Lipsitz, Stuart R; Gail, Mitchell H; Fraumeni, Joseph F Jr; Blaser, Martin J. "Serum antibodies to Helicobacter pylori and the CagA antigen do not explain differences in the prevalence of precancerous gastric lesions in two Chinese populations with contrasting gastric cancer rates". Cancer epidemiology biomarkers & prevention. 2002 Oct;11(10 Pt 1):1091-1094 (MEDL:12376512 #34582)    

    Incidence and mortality rates for gastric cancer in rural People's Republic of China differ greatly over short distances. In Shandong Province, we studied asymptomatic adult subjects from Bei Duan village (n = 196) in Linqu County (a high-risk area for gastric cancer) and from Shi Huang village (n = 192) in Cangshan County (a low-risk area for gastric cancer). The prevalence of advanced precancerous gastric lesions (APGL) was assessed by microscopic examination of endoscopic stomach biopsies. ELISAs were used to detect serum IgG to Helicobacter pylori whole-cell antigen and to the CagA protein. A logistic regression model was used to quantify the role of the two H. pylori seromarkers in explaining the differences in prevalence of APGL between the two villages after adjusting for age and sex. The prevalence of APGL was much greater in Bei Duan than in Shi Huang. Although H. pylori seroprevalence by the whole-cell ELISA was similar in the two populations, seroprevalence of CagA was significantly greater in Bei Duan. Although age, sex, and both H. pylori seromarkers were associated with APGL in the logistic regression model, the effect of village of residence remained strong after adjustment for all four covariates. Only a relatively small proportion of the difference in prevalence of APGL between these two rural Chinese populations can be explained by differences in H. pylori or CagA seroprevalence
  237. Kang, Josephine; Aras, RA; Levine, S; Blaser, Martin J. "The role of Helicobacter pylori mutS and polA in recombination [Meeting Abstract]". Abstracts of the ... general meeting of the American Society for Microbiology. 2002;102:166-166 (BCI:BCI200200585416 #820122)    

    Helicobacter pylori, a gram-negative bacteria that colonizes more than 50% of the world's population is noted for its high level of genetic diversity. A naturally competent organism, H. pylori is capable of genomic diversification through natural transformation and recombination with foreign DNA. Sequencing of H. pylori strains 26695 and J99 have identified several open reading frames (ORFs) with homology to DNA repair genes in other bacterial species; however, their function in H. pylori is unknown. Two genes, mutS and polA, present in both genomes, are known to play a role in DNA repair and recombination in other organisms. For E. coli, mutS and polA mutants increase recombination frequencies 1000- and 100-fold, respectiviely. To examine the role of mutS and polA in H. pylori, we performed PCR using mutS and polA specific primers on 10 H. pylori strains, generated phylogenetic trees for both genes, and created mutants JP26-JKM and JP26-JKP by inserting a kanamycin resistance (aphA) cassette into mutS and polA of strain JP26, respectively. Recombination frequencies of the mutants were examined by transforming them with an 800 bp PCR product that confers streptomycin resistance. PCR analysis of mutS and polA yielded products of the expected size in all strains examined. Phylogenetic studies indicate that both genes are most closely related to homologs in C. jejuni. Transformation frequencies of JP26-JKM (2.9e-6+-2.8e-6) were consistently higher and significantly (p=0.04) different from the transformation frequencies of the wild-type JP26 (8.4e-7+-6.4e-7). For JP26-JKP (2.5e-6+-1.2e-6), transformation frequencies were consistently and significantly (p=0.004) than that of the wild-type JP26. Our findings indicate that mutS and polA are conserved in H. pylori and that they may play a limited role in recombination but to a lesser extent than in other bacterial species (e.g. E. coli). These findings are consistent with sequence analyses indicating a high rate of recombination in H. pylori
  238. Levine, Steven M; Perez-Perez, Guillermo; Olivares, Asalia; Yee, Herman; Hanna, Bruce A; Blaser, Martin J. "PCR-based detection of Bacillus anthracis in formalin-fixed tissue from a patient receiving ciprofloxacin". Journal of clinical microbiology. 2002 Nov;40(11):4360-4362 (MEDL:12409432 #34579)       

    We demonstrate that Bacillus anthracis may be detected from a formalin-fixed, paraffin-embedded biopsy specimen, even after the patient has received antibiotic treatment. Although traditional PCR methods may not be sufficiently sensitive for anthrax detection in such patients, cycle numbers can be increased or PCR can be repeated by using an aliquot from a previous PCR as the template
  239. Limburg, Paul J; Stolzenberg-Solomon, Rachael Z; Colbert, Lisa H; Perez-Perez, Guillermo I; Blaser, Martin J; Taylor, Philip R; Virtamo, Jarmo; Albanes, Demetrius. "Helicobacter pylori seropositivity and colorectal cancer risk: a prospective study of male smokers". Cancer epidemiology biomarkers & prevention. 2002 Oct;11(10 Pt 1):1095-1099 (MEDL:12376513 #34581)    

    Because Helicobacter pylori colonization can produce systemic as well as local effects, it may be associated with carcinogenesis in extra gastric target organs. The currently available data regarding a possible link between H. pylori seropositivity and colorectal cancer risk are limited and inconclusive. In this prospective case-control study nested within the Alpha-Tocopherol, Beta-Carotene Study cohort of Finnish male smokers aged 50-69 years, we examined the association between H. pylori seropositivity and incident colorectal adenocarcinoma. Separate risk estimates were derived by colorectal cancer anatomical subsite and by H. pylori CagA seropositivity status. Demographic, dietary, and lifestyle variables were accounted for in the data analyses using information obtained from a prerandomization questionnaire and physical examination. Baseline serum samples from 118 cases and 236 matched controls were assayed for both H. pylori whole cell and H. pylori CagA antibodies. In total, 258 (73%) and 212 (60%) subjects expressed whole cell and CagA antibodies, respectively. H. pylori seropositivity, defined as one or both antibody assays positive, was present in 273 (77%) subjects. None of the seropositivity results were statistically different between cases and controls. Multivariate odds ratio (95% confidence interval) estimates for whole cell, cagA, and H. pylori seropositivity were 1.05 (0.63-1.74), 1.17 (0.74-1.84), and 0.91 (0.53-1.55), respectively. Stratification by colorectal cancer subsite yielded similarly unremarkable results. On the basis of these data, H. pylori carriage does not appear to be an important risk factor for colorectal adenocarcinoma
  240. Moran, AP; Ferris, JA; Perepelov, AV; Blaser, MJ; Kocharova, NA; Knirel, YA; Wirth, HP; Jansson, PE. "Structural examination of Lewis expression and adaptation in lipopolysacharides of Helicobacter pylori from experimentally infected rhesus monkeys [Meeting Abstract]". Gut: journal of the British Society of Gastroenterology. 2002 SEP;51(2):A15-A15 (ISI:000178344100059 #55585)    
  241. Nomura, Abraham M Y; Lee, James; Stemmermann, Grant N; Nomura, Ryan Y; Perez-Perez, Guillermo I; Blaser, Martin J. "Helicobacter pylori CagA seropositivity and gastric carcinoma risk in a Japanese American population". Journal of infectious diseases. 2002 Oct 15;186(8):1138-1144 (MEDL:12355365 #34583)       

    Helicobacter pylori colonization is associated with gastric cancer, but whether and to what extent the risk is greater for strains with the cagA gene than for those without needs to be determined. Between 1967 and 1977, 9963 Japanese American men were recruited and examined. By 1996, incident cases of gastric carcinoma of the distal stomach had been diagnosed in 261 men. Stored serum samples from these case patients and 261 age-matched control subjects were tested for immunoglobulin G antibodies to H. pylori and to the CagA product of H. pylori, using antibody-specific enzyme-linked immunosorbent assays. Compared with H. pylori-negative, CagA-negative men, H. pylori-positive, CagA-negative men had an odds ratio (OR) of 2.7 (95% confidence interval [CI], 1.3-5.6) for intestinal gastric carcinoma. Men seropositive for both H. pylori and CagA had an OR of 4.1 (95% CI, 2.2-7.7). This suggests that colonization by an H. pylori strain with the cagA gene is associated with a greater risk of intestinal gastric carcinoma
  242. Nomura, Abraham M Y; Perez-Perez, Guillermo I; Lee, James; Stemmermann, Grant; Blaser, Martin J. "Relation between Helicobacter pylori cagA status and risk of peptic ulcer disease". American journal of epidemiology. 2002 Jun 1;155(11):1054-1059 (MEDL:12034584 #34587)       

    Although colonization with any Helicobacter pylori strain is associated with peptic ulcer, it is uncertain whether the risk is greater with cagA(+) or cagA(-) strains, which differ in their biology. A nested case-control study was done, based on a cohort of 5,443 Japanese-American men examined on the Hawaiian island of Oahu from 1967 to 1970. A total of 150 men with gastric ulcer, 65 with duodenal ulcer, and 14 with both diseases were identified. The authors matched the 229 cases with 229 population controls and tested their serum for immunoglobulin G antibodies to H. pylori and immunoglobulin G antibodies to the cagA product of H. pylori using enzyme-linked immunosorbent assays. Persons with H. pylori positivity had an odds ratio of 4.0 (95% confidence interval (CI): 1.9, 8.5) for gastric ulcer and 2.5 (95% CI: 0.8, 7.4) for duodenal ulcer. For CagA positivity, the odds ratios were 1.4 (95% CI: 0.9, 2.4) for gastric ulcer and 2.6 (95% CI: 1.1, 5.8) for duodenal ulcer. Subjects who were seropositive for both H. pylori and CagA had an odds ratio of 4.4 (95% CI: 1.8, 10.5) for gastric ulcer and 5.8 (95% CI: 1.1, 30.0) for duodenal ulcer. The results suggest that colonization with a cag(+) H. pylori strain elevates the risk beyond that of a cag(-) H. pylori strain for both gastric and duodenal ulcers
  243. Peek, Richard M Jr; Blaser, Martin J. "Helicobacter pylori and gastrointestinal tract adenocarcinomas". Nature reviews. Cancer. 2002 Jan;2(1):28-37 (MEDL:11902583 #43546)       

    Although gastric adenocarcinoma is associated with the presence of Helicobacter pylori in the stomach, only a small fraction of colonized individuals develop this common malignancy. H. pylori strain and host genotypes probably influence the risk of carcinogenesis by differentially affecting host inflammatory responses and epithelial-cell physiology. Understanding the host-microbial interactions that lead to neoplasia will improve cancer-targeted therapeutics and diagnostics, and provide mechanistic insights into other malignancies that arise within the context of microbially initiated inflammatory states
  244. Perez-Perez, G I; Salomaa, A; Kosunen, T U; Daverman, B; Rautelin, H; Aromaa, A; Knekt, P; Blaser, M J. "Evidence that cagA(+) Helicobacter pylori strains are disappearing more rapidly than cagA(-) strains". Gut: journal of the British Society of Gastroenterology. 2002 Mar;50(3):295-298 (MEDL:11839704 #25600)       

    Background and aims: The prevalence of Helicobacter pylori colonisation in populations in developed country has been declining, as shown by community based serological surveys of adults in Vammala, Finland in 1973 and 1994. In this study, we determined whether the proportion of subjects colonised by cagA(+) or cagA(-) H pylori strains has changed as the overall prevalence of H pylori(+) has declined. Methods: We examined 911 sera from Vammala's study for antibodies to the CagA antigen of H pylori using a truncated CagA protein as the antigen in an ELISA and we examined the trend in acquisition and carriage of cagA(+) strains. Results: As expected, the prevalence of carriage of both cagA(+) and cagA(-) strains fell between 1973 and 1994 (p<0.001). However, the prevalence of cagA(+) strains among those <45 years declined (34% to 8%) significantly (p<0.001) more than for cagA(-) strains (12% to 6%). Of 221 subjects with paired serum samples, 12 (5.4%) changed H pylori status; the estimated seroconversion and reversion rates were 0.4% and 0.13% per year, respectively. Except for the few individuals who changed serostatus, absolute antibody levels to H pylori antigens, including CagA, changed little over the 21 year period. Conclusions: The decline in CagA seroprevalence predominantly reflects declining acquisition of cag(+) strains in younger subjects. In addition, these data confirm that H pylori acquisition chiefly occurs during childhood but continues to occur during adulthood, albeit at low rates, in developed countries
  245. Perez-Perez, GI; Olivares, AZ; Peek, RM; Tham, K; Blaser, MJ. "Detection of Helicobacter pylori in gastric juice by PCR [Meeting Abstract]". Gut: journal of the British Society of Gastroenterology. 2002 SEP;51(2):A110-A110 (ISI:000178344100384 #55589)    
  246. Pride, David T; Blaser, Martin J. "Concerted evolution between duplicated genetic elements in Helicobacter pylori". Journal of molecular biology. 2002 Feb 22;316(3):629-642 (MEDL:11866522 #43548)       

    The Helicobacter pylori genome includes a family of outer membrane proteins (OMPs) with substantial N and C-terminal identity. To better understand their evolution, the nucleotide sequences for two members, babA and babB, were determined from a worldwide group of 23 strains. The geographic origin of each strain was found to be the major determinant of phylogenetic structure, with strains of Eastern and Western origin showing greatest divergence. For strains 96-10 (Japan) and 96-74 (USA), the 5' regions of babB are replaced with babA sequences, demonstrating that recombination occurs between the two loci. babA and babB have nearly equivalent variation in nucleotide and amino acid identity, and frequencies of synonymous and non-synonymous substitutions. Both genes have segmental conservation but within the 3' segment, substitution patterns are nearly identical. Although babA and babB 5' and midregion segment phylogenies show strong interstrain similarity, the 3' segments show strong intrastrain similarity, indicative of concerted evolution. Within these 3' segments, the lower intrastrain than interstrain frequencies of nucleotide substitutions, which are below mean background H. pylori substitution frequencies, indicate selection against intrastrain diversification. Since babA/babB gene conversions likely underlie the concerted evolution of the 3' segments, in an experimental system, we demonstrate that gene conversions can frequently (10(-3)) occur in H. pylori. That these events are recA-dependent and DNase-resistant indicates their likely cause is intragenomic recombination
  247. Romero-Gallo, Judith; Perez-Perez, Guillermo I; Novick, Richard P; Kamath, Patrick; Norbu, Tsering; Blaser, Martin J. "Responses of endoscopy patients in Ladakh, India, to Helicobacter pylori whole-cell and Cag A antigens". Clinical & diagnostic laboratory immunology. 2002 Nov;9(6):1313-1317 (MEDL:12414766 #34578)       

    Although Helicobacter pylori is a cosmopolitan colonizer of the human stomach, the responses among persons in remote populations from whom H. pylori was cultured have not been studied. We report on studies of 189 persons in the Ladakh region of India in whom serum immunoglobulin G responses to H. pylori whole-cell and Cag A antigens were measured. H. pylori was isolated from 68 of these patients. An H. pylori whole-cell antigen derived from Ladakhi strains outperformed a similar antigen from U.S. strains, as determined by antigen-specific enzyme-linked immunosorbent assays. In total, 95% of the population was seropositive, including individuals responding only to the Cag A antigen. Correlation with culture results showed that these were true positives and, therefore, that the H. pylori whole-cell serology was falsely negative in some cases. In addition to establishing a collection of H. pylori isolates from a remote area in the world, we show that use of H. pylori whole-cell and Cag A serology together increases the sensitivity for the detection of colonization
  248. Takata, Tohru; Aras, Rahul; Tavakoli, Donald; Ando, Takafumi; Olivares, Asalia Z; Blaser, Martin J. "Phenotypic and genotypic variation in methylases involved in type II restriction-modification systems in Helicobacter pylori". Nucleic acids research. 2002 Jun 1;30(11):2444-2452 (MEDL:12034832 #34586)       

    To determine relationships between Helicobacter pylori geographical origin and type II methylase activity, we examined 122 strains from various locations around the world for methylase expression. Most geographic regions possessed at least one strain resistant to digestion by each of 14 restriction endonucleases studied. Across all of the strains studied, the average number of active methylases was 8.2 +/- 1.9 with no significant variation between the major geographic regions. Although seven pairs of isolates showed the same susceptibility patterns, their cagA/vacA status differed, and the remaining 108 strains each possessed unique patterns of susceptibility. From a single clonal group, 15 of 18 strains showed identical patterns of resistance, but diverged with respect to M.MboII activity. All of the methylases studied were present in all major human population groupings, suggesting that their horizontal acquisition pre-dated the separation of these populations. For the hpyV and hpyAIV restriction-modification systems, an in-depth analysis of genotype, indicating extensive diversity of cassette size and chromosomal locations regardless of the susceptibility phenotype, points toward substantial strain-specific selection involving these loci
  249. Takata, Tohru; El-Omar, Emad; Camorlinga, Margarita; Thompson, Stuart A; Minohara, Yutaka; Ernst, Peter B; Blaser, Martin J. "Helicobacter pylori does not require Lewis X or Lewis Y expression to colonize C3H/HeJ mice". Infection & immunity. 2002 Jun;70(6):3073-3079 (MEDL:12011000 #43543)       

    Helicobacter pylori strains frequently express Lewis X (Le(x)) and/or Le(y) on their cell surfaces as constituents of the O antigens of their lipopolysaccharide molecules. To assess the effect of Le(x) and Le(y) expression on the ability of H. pylori to colonize the mouse stomach and to adhere to epithelial cells, isogenic mutants were created in which fucT1 alone or fucT1 and fucT2, which encode the fucosyl transferases necessary for Le(x) and Le(y) expression, were deleted. C3H/HeJ mice were experimentally challenged with either wild-type 26695 H. pylori or its isogenic mutants. All strains, whether passaged in the laboratory or recovered after mouse passage, colonized the mice well and without consistent differences. During colonization by the mutants, there was no reversion to wild type. Similarly, adherence to AGS and KatoIII cells was unaffected by the mutations. Together, these findings indicate that Le expression is not necessary for mouse gastric colonization or for H. pylori adherence to epithelial cells
  250. Wassenaar, Trudy M; Blaser, Martin J. "Contagion on the Internet [Letter]". Emerging infectious diseases. 2002 Mar;8(3):335-336 (MEDL:11927037 #43545)    
  251. Webb, G F; Blaser, M J. "Dynamics of bacterial phenotype selection in a colonized host". Proceedings of the National Academy of Sciences of the United States of America. 2002 Mar 5;99(5):3135-3140 (MEDL:11867714 #43547)       

    The population dynamics of Helicobacter pylori during colonization in an infected animal host provide a quantifiable experimental model of in vivo microbial phenotype evolution. Phenotype variability in H. pylori populations can be typed as polymorphic expression of Lewis antigens on their cell surfaces. The high mutational frequency of H. pylori for Lewis expression provides substrate for differential selection by the host. Experimental challenge and successful colonization of mice and gerbils allows tracking of H. pylori phenotype variability from the initial inoculation to the ultimate establishment of a quasispecies. Colonization data provide a quantitative experimental model of phenotype evolution in a relatively large population (>10(4) individuals) over a relatively long evolutionary time scale (>10(3) generations). A mathematical model is developed to interpret the data in terms of the dynamic processes occurring during colonization. The mathematical model distinguishes the roles of selection and mutation; quantifies the effects of initial phenotype diversity, mutational frequency, and selective advantage; and applies generally to phenotype evolution in biological populations
  252. Webb, Glenn F; Blaser, Martin J. "Mailborne transmission of anthrax: Modeling and implications". Proceedings of the National Academy of Sciences of the United States of America. 2002 May 14;99(10):7027-7032 (MEDL:12011462 #43542)       

    A mathematical model is developed to analyze the transmission of inhalational anthrax through the postal system by cross-contamination of mail. The model consists of state vectors describing the numbers of cross-contaminated letters generated, the numbers of anthrax spores on these letters, the numbers of resulting infections in recipients, and matrices of transition probabilities acting on these vectors. The model simulates the recent outbreak in the United States, and provides a general framework to investigate the potential impact of possible future outbreaks
  253. Xu, Qing; Morgan, R D; Roberts, R J; Xu, S Y; van Doorn, L J; Donahue, J P; Miller, G G; Blaser, Martin J. "Functional analysis of iceA1, a CATG-recognizing restriction endonuclease gene in Helicobacter pylori". Nucleic acids research. 2002 Sep 1;30(17):3839-3847 (MEDL:12202769 #34584)       

    iceA1 in Helicobacter pylori is a homolog of nlaIIIR, which encodes the CATG-specific restriction endonuclease NlaIII in Neisseria lactamica. Analysis of iceA1 sequences from 49 H.pylori strains shows that a full-length NlaIII-like ORF is present in 10 strains, including CH4, but in other strains, including strain 60190, the ORFs are truncated due to a variety of mutations. Our goal was to determine whether iceA1 can encode a NlaIII-like endonuclease. Overexpression in Escherichia coli of iceA1 from CH4, but not from 60190, yielded NlaIII-like activity, indicating that the full-length iceA1 is a functional endonuclease gene. Repair of the iceA1 frameshift mutation in strain 60190 and its expression in E.coli yielded functional NlaIII-like activity. We conclude that iceA1 in CH4 is a functional restriction endonuclease gene, while iceA1 in 60190 is not, due to a frameshift mutation, but that its repair restores its restriction endonuclease activity
  254. Ando, T; Peek, RM; Kusugami, K; Blaser, MJ. "Comparison of IL-8 and apoptosis induction by cagA+ vacA s1/m1 H. pylori strains from the US and Japan [Meeting Abstract]". Gastroenterology. 2001 APR;120(5):A671-A671 (ISI:000168514703332 #55039)    
  255. Ando, T; Peek, RM; Levine, SM; Kusugami, K; Lee, YC; Van der Ende, A; Kusters, JG; Takata, T; Blaser, MJ. "Diversity of Helicobacter pylori HP0638, encoding OipA, correlates with cagA status and geographic origin [Meeting Abstract]". Gastroenterology. 2001 APR;120(5):A723-A723 (ISI:000168514703595 #55040)    
  256. Aras RA; Takata T; Ando T; van der Ende A; Blaser MJ. "Regulation of the HpyII restriction-modification system of Helicobacter pylori by gene deletion and horizontal reconstitution". Molecular microbiology. 2001 Oct;42(2):369-382 (MEDL:11703661 #32230)       

    Helicobacter pylori, Gram-negative, curved bacteria colonizing the human stomach, possess strain-specific complements of functional restriction-modification (R-M) systems. Restriction-modification systems have been identified in most bacterial species studied and are believed to have evolved to protect the host genome from invasion by foreign DNA. The large number of R-Ms homologous to those in other bacterial species and their strain-specificity suggest that H. pylori may have horizontally acquired these genes. A type IIs restriction-modification system, hpyIIRM, was active in two out of the six H. pylori strains studied. We demonstrate now that in most strains lacking M.HpyII function, there is complete absence of the R-M system. Direct DNA repeats of 80 bp flanking the hpyIIRM system allow its deletion, resulting in an 'empty-site' genotype. We show that strains possessing this empty-site genotype and strains with a full but inactive hpyIIRM can reacquire the hpyIIRM cassette and functional activity through natural transformation by DNA from the parental R-M+ strain. Identical isolates divergent for the presence of an active HpyII R-M pose different restriction barriers to transformation by foreign DNA. That H. pylori can lose HpyII R-M function through deletion or mutation, and can horizontally reacquire the hpyIIRM cassette, is, in composite, a novel mechanism for R-M regulation, supporting the general hypothesis that H. pylori populations use mutation and transformation to regulate gene function
  257. Blaser MJ; Berg DE. "Helicobacter pylori genetic diversity and risk of human disease". Journal of clinical investigation. 2001 Apr;107(7):767-773 (MEDL:11285290 #19026)       
  258. Blaser MJ; Musser JM. "Bacterial polymorphisms and disease in humans". Journal of clinical investigation. 2001 Feb;107(4):391-392 (MEDL:11181636 #19032)       
  259. Figueiredo C; Quint W; Nouhan N; van Den Munckhof H; Herbrink P; Scherpenisse J; de Boer W; Schneeberger P; Perez-Perez G; Blaser MJ; van Doorn LJ. "Assessment of Helicobacter pylori vacA and cagA Genotypes and Host Serological Response". Journal of clinical microbiology. 2001 Apr;39(4):1339-1344 (MEDL:11283053 #19027)       

    Helicobacter pylori strains can be distinguished by genotyping of virulence-associated genes, such as vacA and cagA. Because serological discrimination between strain types would reduce the need for endoscopy, 61 patients carrying H. pylori were studied by vacA and cagA genotyping of H. pylori in gastric biopsy specimens and by detection of specific serum antibodies. Serological responses to H. pylori were determined by Helicoblot (versions 2.0 and 2.1). Antibodies to CagA also were determined by a rapid anti-CagA assay (Pyloriset screen CagA) as well as by two noncommercially developed enzyme immunoassays, each using a recombinant CagA protein. Assessment of performance of the Helicoblot assays indicated substantial interobserver variation, with kappa values between 0.20 and 0.93. There was no relationship between the serological profiles on the Helicoblot and the genotypes from the same patients, except for strong associations between the presence of anti-CagA and the cagA-positive and vacA s1 H. pylori genotypes. Detection of anti-CagA by the five different assays varied considerably, with kappa values ranging from 0.21 to 0.78. Using the cagA genotype as the 'gold standard,' the sensitivity and specificity of the anti-CagA assays varied from 71.4 to 85.7% and from 54.2 to 100%, respectively. Thus, serological profiles of antibodies to H. pylori are heterogeneous and, with the exception of anti-CagA antibodies, show no relation to the H. pylori vacA and cagA genotypes. Detection of anti-CagA antibodies is strongly dependent on the test used
  260. Ghose, C; Perez-Perez, GI; Dominguez-Bello, MG; Blaser, MJ. "Helicobacter pylori among indigenous peoples of Venezuela: European or Asian origin? [Meeting Abstract]". Clinical infectious diseases. 2001 OCT 1;33(7):1233-1233 (ISI:000171226900871 #54859)    
  261. Israel DA; Salama N; Arnold CN; Moss SF; Ando T; Wirth HP; Tham KT; Camorlinga M; Blaser MJ; Falkow S; Peek RM. "Helicobacter pylori strain-specific differences in genetic content, identified by microarray, influence host inflammatory responses". Journal of clinical investigation. 2001 Mar;107(5):611-620 (MEDL:11238562 #19031)       

    Helicobacter pylori enhances the risk for ulcer disease and gastric cancer, yet only a minority of H. pylori-colonized individuals develop disease. We examined the ability of two H. pylori isolates to induce differential host responses in vivo or in vitro, and then used an H. pylori whole genome microarray to identify bacterial determinants related to pathogenesis. Gastric ulcer strain B128 induced more severe gastritis, proliferation, and apoptosis in gerbil mucosa than did duodenal ulcer strain G1.1, and gastric ulceration and atrophy occurred only in B128+ gerbils. In vitro, gerbil-passaged B128 derivatives significantly increased IL-8 secretion and apoptosis compared with G1.1 strains. DNA hybridization to the microarray identified several strain-specific differences in gene composition including a large deletion of the cag pathogenicity island in strain G1.1. Partial and complete disruption of the cag island in strain B128 attenuated induction of IL-8 in vitro and significantly decreased gastric inflammation in vivo. These results indicate that the ability of H. pylori to regulate epithelial cell responses related to inflammation depends on the presence of an intact cag pathogenicity island. Use of an H pylori whole genome microarray is an effective method to identify differences in gene content between H. pylori strains that induce distinct pathological outcomes in a rodent model of H. pylori infection
  262. Lew, EA; Risch, HA; Chow, WH; Gammon, MD; Vaughan, TL; Schoenberg, JB; Stanford, JL; West, AB; Rotterdam, H; Blot, WJ; Blaser, MJ; Fraumeni, JF. "Helicobacter pylori, gastroesophageal reflux, their interrelationships, and the risk of esophageal adenocarcinoma [Meeting Abstract]". Gastroenterology. 2001 APR;120(5):A31-A31 (ISI:000168514700150 #55028)    
  263. Limburg P; Qiao Y; Mark S; Wang G; Perez-Perez G; Blaser M; Wu Y; Zou X; Dong Z; Taylor P; Dawsey S. "Helicobacter pylori seropositivity and subsite-specific gastric cancer risks in Linxian, China". Journal of the National Cancer Institute. 2001 Feb 7;93(3):226-233 (MEDL:11158192 #34627)       

    BACKGROUND: Helicobacter pylori carriage (i.e., persistent exposure to the organism without gastric epithelial cell invasion) is an established risk factor for noncardia gastric cancer. However, its association with the risk of cancer of the gastric cardia is controversial. Consequently, we designed this prospective, nested case-control study to further explore the subsite-specific gastric cancer risks associated with H. pylori seropositivity (a surrogate marker for persistent exposure). METHODS: A total of 99 patients with gastric cardia cancer, 82 patients with noncardia gastric cancer, and 192 cancer-free subjects were selected from among the participants (n = 29 584) of a nutrition intervention trial previously conducted in Linxian, China. H. pylori seropositivity was determined by assaying for the presence of H. pylori whole cell and CagA antibodies in baseline serum samples from all subjects. Seropositivity was defined as one or both serum assays being positive. Odds ratios (ORs) for subsite-specific gastric cancer were estimated by multivariate logistic regression analyses. All statistical comparisons were two-sided (alpha =.05). RESULTS: H. pylori seropositivity rates for subjects with gastric cardia cancer, noncardia gastric cancer, and gastric cardia and noncardia cancers combined were 70% (P =.02), 72% (P: =.01), and 71% (P =.003) compared with 56% for cancer-free control subjects. OR estimates for H. pylori seropositivity were 1.87 (95% confidence interval [CI] = 1.10 to 3.17) for gastric cardia cancer, 2.29 (95% CI = 1.26 to 4.14) for noncardia gastric cancer, and 2.04 (95% CI = 1.31 to 3.18) for gastric cardia and noncardia cancers combined. CONCLUSIONS: H. pylori seropositivity was associated with increased risks for both gastric cardia cancer and noncardia gastric cancer in this well-characterized cohort. Thus, H. pylori carriage may increase the risk of cancer throughout the stomach
  264. Misawa N; Kawashima K; Kondo F; Allos BM; Blaser MJ. "DNA diversity of the wla gene cluster among serotype HS:19 and non-HS:19 Campylobacter jejuni strains". Journal of endotoxin research. 2001;7(5):349-358 (MEDL:11753203 #43549)       

    Campylobacter jejuni infection is an important trigger of Guillain-Barre syndrome (GBS), and serotype HS:19 strains are over-represented among GBS-associated isolates. Structures in C. jejuni lipooligosaccharide (LOS) resemble human gangliosides, suggesting that molecular mimicry could be important in triggering the neural injury. We assessed the genetic diversity among 36 C. jejuni serotype HS:19 and non-HS:19 strains by analysis of PCR-based restriction fragment length polymorphism (RFLP) patterns of 12 LOS biosynthesis-related genes (wla cluster). PCR amplification revealed that the size, order, and direction of each wla gene was identical among all strains tested. However, an additional ORF, located between wlaI and wlaK, was detected in 28 of the 36 isolates examined, and nucleotide sequence analysis revealed that the gene was identical to orfE in C. jejuni strain NCTC 11168. An inverted repeat motif was found downstream of the wlaI stop codon and upstream of the orfE stop codon, an organization allowing pairing of repeated sequences that could lead to deletion of the internal segment. Digestion of the PCR products with restriction endonuclease DdeI or AluI and cluster analysis of RFLP banding patterns showed that all HS:19 strains were closely related and distinct from non-HS:19 strains, consistent with earlier analyses, suggesting that HS:19 strains represent a highly clonal population. RFLP analysis of wla genes also may be useful for epidemiological studies
  265. Moss SF; Sordillo EM; Abdalla AM; Makarov V; Hanzely Z; Perez-Perez GI; Blaser MJ; Holt PR. "Increased gastric epithelial cell apoptosis associated with colonization with cagA + Helicobacter pylori strains". Cancer research. 2001 Feb 15;61(4):1406-1411 (MEDL:11245442 #19030)    

    Gastric colonization by Helicobacter pylori is a risk factor for noncardia gastric cancer. The association between H. pylori and cancer may be attributable to increased epithelial cell turnover, possibly related to antigastric antibodies. Two previous studies reported a disproportionate increase in proliferation relative to apoptosis in patients with H. pylori strains expressing the virulence-related cagA gene. This has led to the hypothesis that an abrogation of apoptosis by cagA-positive strains may promote neoplasia. We, therefore, examined the effect of H. pylori on gastric epithelial proliferation, apoptosis, and the presence of serum antiparietal cell antibodies in a large prospective study. Proliferation and apoptosis were evaluated 'blindly' using validated immunohistochemical methods in two antral and two gastric corpus biopsies from 60 patients with nonulcer dyspepsia, and results were correlated with the presence of serum antiparietal cell antibodies. H. pylori colonization was assessed by histology, biopsy urease test, and serology. Proliferation was increased 2-fold in both antrum and corpus in H. pylori-positive patients, was not related to H. pylori cagA status, and was positively correlated with histological gastritis. Apoptosis was increased in the antrum and body only in patients with cagA-positive H. pylori strains. Antiparietal cell antibodies were not more prevalent in H. pylori colonization, and their presence was inversely related to epithelial apoptosis scores we therefore conclude that in patients with nonulcer dyspepsia, H. pylori carriage is associated with increased proliferation. Futhermore the cag pathogenicity island is associated with increased apoptosis. Our results do not support the hypothesis that there is a relative deficiency of gastric epithelial cell apoptosis associated with the carriage of cagA-positive strains. Host factors may be more important than bacterial products in determining the long-term outcome of H. pylori colonization
  266. Perez-Perez, GI; Dominguez-Bello, MG; Ghose, C; Pacheco, N; Gonzalez, E; Mago, V; de Novoa, PG; Gomez, I; Mora, R; Blaser, MJ. "Presence of specific Asian Helicobacter pylori genotypes in Amerindians in Venezuela [Meeting Abstract]". Gut: journal of the British Society of Gastroenterology. 2001 SEP;49(4):A33-A33 (ISI:000171232500115 #54871)    
  267. Pride DT; Meinersmann RJ; Blaser MJ. "Allelic Variation within Helicobacter pylori babA and babB". Infection & immunity. 2001 Feb;69(2):1160-1171 (MEDL:11160014 #19033)       

    Helicobacter pylori strains show both geographic and disease-associated allelic variation. We investigated the diversity present in two genes, babA and babB, which are members of a paralogous family of outer membrane proteins. Eleven family members within a single H. pylori strain, predicted to encode proteins with substantial N- and C-terminal similarity to each other, were classified as babA paralogues. In their central regions, most are less than 54% related to one another. Examining the babA and babB central regions in 42 H. pylori strains from different geographic locales, we identified five different allele groups of babA (AD1 to AD5) and three different allele groups of babB (BD1 to BD3). Phylogenetic analysis revealed that the allelic groupings of babA and babB are independent of one another and that, for both, geographic variation is present. Analysis of synonymous and nonsynonymous substitutions in these regions showed that babA is more diverse, implying an earlier origin than that of the same region of babB, but that the babA diversity region may have more functional constraints. Although recombination has been central to the evolution of both genes, with babA and babB showing low mean compatibility scores and homoplasy ratios of 0.71 and 0.67, respectively, recombination is not sufficient to obscure evidence of clonal descent. Despite the involvement of babA in binding to the host blood group antigen Lewis B, neither the presence of different babA allele groups nor that of different babB allele groups is a determining factor in Lewis B binding of H. pylori strains
  268. Sozzi M; Crosatti M; Kim SK; Romero J; Blaser MJ. "Heterogeneity of Helicobacter pylori cag genotypes in experimentally infected mice". FEMS microbiology letters. 2001 Sep 11;203(1):109-114 (MEDL:11557148 #43550)       

    Our aim was to assess whether the Helicobacter pylori population recovered from experimentally infected mice show heterogeneity in cag genotypes. Wild-type FVB/N mice were challenged with strain Hp1 and sacrificed 8 weeks later. Direct PCR on gastric tissue was performed using primers for glmM and cagA, and for these two genes and for cagE and virB11 using DNA from the infecting and the emerging strains. The gastric tissues of two of five mice were PCR+ for glmM but not cagA. For the infecting strain, the PCRs for all four genes studied were strongly positive, but the sweeps from the emerging strains from both mice gave weaker signals for cagA and cagE. Examination of single colonies showed reduced or absent signals for cagA and cagE in relation to glmM and virB11. Serial dilution PCR of sweep isolates from the mice showed a 10- to 100-fold decrease in cagA signal compared to the infecting strain. The decrease of cagA and cagE, but not virB11, amplification and lack of cagA hybridization in Southern blots indicates a selective loss of the right half of the cag island during murine infection. This phenomenon is consistent with host-induced adaptive changes of cag genotype in the population of colonizing H. pylori cells
  269. Stolzenberg-Solomon RZ; Blaser MJ; Limburg PJ; Perez-Perez G; Taylor PR; Virtamo J; Albanes D. "Helicobacter pylori seropositivity as a risk factor for pancreatic cancer". Journal of the National Cancer Institute. 2001 Jun 20;93(12):937-941 (MEDL:11416115 #34624)       

    BACKGROUND: Pancreatic cancer is among the most fatal cancers worldwide and one for which few preventable risk factors have been established. Gastric carriage of Helicobacter pylori, particularly cytotoxin-associated gene-A-positive (CagA+) strains, is known to be a risk factor for peptic ulcer disease and gastric cancer and may have a similar etiologic relationship with pancreatic cancer. METHODS: We investigated the association of H. pylori carriage and exocrine pancreatic cancer in a nested case-control study within the Alpha-Tocopherol, Beta-Carotene Cancer Prevention Study cohort of 29 133 male Finnish smokers aged 50-69 years at baseline. Case subjects (n = 121) were matched on date of baseline serum collection, study center, age, trial intervention, and completion of the dietary questionnaire to 226 control subjects who were alive at the time the matching case subject was diagnosed and who remained free of cancer, during up to 10 years of follow-up. Levels of immunoglobulin G antibodies to H. pylori whole-cell and CagA+ antigens from stored baseline serum were measured by enzyme-linked immunosorbent assay. Smoking-adjusted odds ratios (ORs) and 95% confidence intervals (CIs) were estimated by use of conditional logistic regression. Statistical tests were two-sided. RESULTS: Seroprevalence of H. pylori was 82% and 73% among case and control subjects, respectively. Compared with seronegative subjects, those with H. pylori or CagA+ strains were at statistically significantly elevated risk of pancreatic cancer (OR = 1.87 [95% CI = 1.05 to 3.34]; OR = 2.01 [95% CI = 1.09 to 3.70], respectively). CONCLUSIONS: Our findings support a possible role for H. pylori carriage in the development of exocrine pancreatic cancer
  270. Tham KT; Peek RM; Atherton JC; Cover TL; Perez-Perez GI; Shyr Y; Blaser MJ. "Helicobacter pylori genotypes, host factors, and gastric mucosal histopathology in peptic ulcer disease". Human pathology. 2001 Mar;32(3):264-273 (MEDL:11274634 #19028)       

    From 183 patients undergoing upper gastrointestinal endoscopy, we used antral and corpus gastric biopsies for bacterial culture and histopathologic examination, blood samples to detect immunoglobulin G antibodies against Helicobacter pylori, and H pylori genomic DNA to analyze cytotoxin-associated gene A (cagA) and vacuolating cytotoxin (vacA) genotypes. As expected, among H pylori biopsy-positive patients, those with duodenal ulcer (DU) (n = 34) had significantly more severe chronic and acute inflammation (P <.001) and epithelial degeneration (P =.004) in the gastric antrum than in the gastric corpus. Each of those 3 parameters and H pylori density were significantly higher in the antrum of patients with DU than in patients with gastric ulcer (GU) or no ulcer. Colonization with vacA s1/cagA-positive strains of H pylori was associated with inflammation and epithelial degeneration in gastric mucosa and increased risk for peptic ulcer disease (PUD), whereas colonization with vacA s2m2/cagA-negative strains was associated with mild gastric histopathology and was not associated with any significant risk for PUD. The predominant H pylori strains in African Americans were vacA s1bm1/cagA-positive, whereas all genotypes were well represented in non-Hispanic-Caucasians. By multivariate analysis, H pylori colonization was significantly associated with DU (Adjusted odds ratio [AdjOR] = 3.2 [1.4-7.2]) and nonsteroidal anti-inflammatory drugs (NSAID) use was inversely associated (AdjOR = 0.3 [0.2-0.7]). NSAID use (AdjOR = 4.3 [1.02-18.5]) and African-American ethnicity (AdjOR = 10.9 [2.6-50]) were significantly associated with GU. Smoking and age were not significantly associated with either DU or GU. These data indicate that DU is associated with an antral-dominant gastritis, and H pylori genotype and NSAID use independently contribute to the pathogenesis of PUD. HUM PATHOL 32:264-273. This is a US Government work. There are no restrictions on its use
  271. Tu ZC; Dewhirst FE; Blaser MJ. "Evidence that the Campylobacter fetus sap locus is an ancient genomic constituent with origins before mammals and reptiles diverged". Infection & immunity. 2001 Apr;69(4):2237-2244 (MEDL:11254579 #19029)       

    Campylobacter fetus bacteria, isolated from both mammals and reptiles, may be either subsp. fetus or subsp. venerealis and either serotype A or serotype B. Surface layer proteins, expressed and secreted by genes in the sap locus, play an important role in C. fetus virulence. To assess whether the sap locus represents a pathogenicity island and to gain further insights into C. fetus evolution, we examined several C. fetus genes in 18 isolates. All of the isolates had 5 to 9 sapA or sapB homologs. One strain (85-387) possessed both sapA and sapB homologs, suggesting a recombinational event in the sap locus between sapA and sapB strains. When we amplified and analyzed nucleotide sequences from portions of housekeeping gene recA (501 bp) and sapD (450 bp), a part of the 6-kb sap invertible element, the phylogenies of the genes were highly parallel. Among the 15 isolates from mammals, serotype A and serotype B strains generally had consistent positions. The fact that the serotype A C. fetus subsp. fetus and subsp. venerealis strains were on the same branch suggests that their differentiation occurred after the type A-type B split. Isolates from mammals and reptiles formed two distinct tight phylogenetic clusters that were well separated. Sequence analysis of 16S rRNA showed that the reptile strains form a distinct phylotype between mammalian C. fetus and Campylobacter hyointestinalis. The phylogenies and sequence results showing that sapD and recA have similar G + C contents and substitution rates suggest that the sap locus is not a pathogenicity island but rather is an ancient constituent of the C. fetus genome, integral to its biology
  272. Tu ZC; Ray KC; Thompson SA; Blaser MJ. "Campylobacter fetus uses multiple loci for DNA inversion within the 5' conserved regions of sap homologs". Journal of bacteriology. 2001 Nov;183(22):6654-6661 (MEDL:11673436 #26593)       

    Campylobacter fetus cells possess multiple promoterless sap homologs, each capable of expressing a surface layer protein (SLP) by utilizing a unique promoter present on a 6.2-kb invertible element. Each sap homolog includes a 626-bp 5' conserved region (FCR) with 74 bp upstream and 552 bp within the open reading frame. After DNA inversion, the splice is seamless because the FCRs are identical. In mutant strain 23D:ACA2K101, in which sapA and sapA2 flanking the invertible element in opposite orientations were disrupted by promoterless chloramphenicol resistance (Cm(r)) and kanamycin resistance (Km(r)) cassettes, respectively, the frequency of DNA inversion is 100-fold lower than that of wild-type strain 23D. To define the roles of a 15-bp inverted repeat (IR) and a Chi-like site (CLS) in the FCR, we mutagenized each upstream of sapA2 in 23D:ACA2K101 by introducing NotI and KpnI sites to create strains 23D:ACA2K101N and 23D:ACA2K101K, respectively. Alternatively selecting colonies for Cm(r) or Km(r) showed that mutagenizing the IR or CLS had no apparent effect on the frequency of the DNA inversion. However, mapping the unique NotI or KpnI site in relation to the Cm(r) or Km(r) cassette in the cells that changed phenotype showed that splices occurred both upstream and downstream of the mutated sites. PCR and sequence analyses also showed that the splice could occur in the 425-bp portion of the FCR downstream of the cassettes. In total, these data indicate that C. fetus can use multiple sites within the FCR for its sap-related DNA inversion
  273. Xu Q; Blaser MJ. "Promoters of the CATG-specific methyltransferase gene hpyIM differ between iceA1 and iceA2 Helicobacter pylori strains". Journal of bacteriology. 2001 Jul;183(13):3875-3884 (MEDL:11395450 #43551)       

    Helicobacter pylori strains can be divided into two groups, based on the presence of two unrelated genes, iceA1 and iceA2, that occupy the same genomic locus. hpyIM, located immediately downstream of either gene, encodes a functional CATG-specific methyltransferase. Despite the strong conservation of the hpyIM open reading frame (ORF) among all H. pylori strains, the sequences upstream of the ORF in iceA1 and iceA2 strains are substantially different. To explore the roles of these upstream sequences in hpyIM regulation, promoter analysis of hpyIM was performed. Both deletion mutation and primer extension analyses demonstrate that the hpyIM promoters differ between H. pylori strains 60190 (iceA1) and J188 (iceA2). In strain 60190, hpyIM has two promoters, P(a) or P(I), which may function independently, whereas only one hpyIM promoter, P(c), was found in strain J188. The XylE assay showed that the hpyIM transcription level was much higher in strain 60190 than in strain J188, indicating that regulation of hpyIM transcription differs between the H. pylori iceA1 strain (60190) and iceA2 strains (J188). Since the iceA1 and iceA2 sequences are highly conserved within iceA1 or iceA2 strains, we conclude that promoters of the CATG-specific methylase gene hpyIM differ between iceA1 and iceA2 strains, which leads to differences in regulation of hpyIM transcription
  274. You WC; Zhang L; Pan KF; Jiang J; Chang YS; Perez-Perez GI; Liu WD; MA JL; Gail MH; Blaser MJ; Fraumeni JF; Xu GW. "Helicobacter pylori prevalence and CagA status among children in two counties of China with high and low risks of gastric cancer". Annals of epidemiology. 2001 Nov;11(8):543-546 (MEDL:11709273 #25601)       

    BACKGROUND: Studies in adult populations in selected countries with widely varying rates of gastric cancer have shown a weak correlation between gastric cancer mortality rates and the prevalence of CagA+ strains of H. pylori. However, only limited data are available in ethnically homogenous populations with varying rates in the same region. METHODS; We compared the prevalence of H. pylori in general and of CagA+ strains in particular among children in Shandong Province, China in areas at high (Linqu County) and low risk (Cangshan County) of gastric cancer. H. pylori status among children aged 3 to 12 years was determined by 13C-UBT, and CagA status was determined by enzyme-linked immunosorbent assay (ELISA). Because of the difficulty in obtaining blood from young children aged 3 to 4 years and from some children aged 5 years, CagA status was determined among part of children 5 years old and children 6 to 12 years old. RESULTS; Among 98 children aged 3 to 12 years in Linqu, 68 (69.4%) was H. pylori-positive, as compared with 29 (28.7%) among 101 children in Cangshan. Among children positive for 13C-UBT, the proportion of the CagA+ strains were identified was 46 (88.5%) of 52 in Linqu and 13 (81.3%) of 16 in Cangshan, respectively. CONCLUSIONS: The prevalence of H. pylori was nearly three times higher among children in Linqu than in Cangshan, which may contribute to the large differential in gastric cancer rates for two neighboring populations in Shandong Province
  275. Ando T; Perez-Perez GI; Kusugami K; Ohsuga M; Bloch KC; Blaser MJ. "Anti-CagA immunoglobulin G responses correlate with interleukin-8 induction in human gastric mucosal biopsy culture". Clinical & diagnostic laboratory immunology. 2000 Sep;7(5):803-809 (MEDL:10973458 #19041)       

    Helicobacter pylori persists in the human stomach despite eliciting both cellular and humoral immune responses and inducing proinflammatory cytokines. To determine whether local humoral and cytokine responses are related to each other and to histologic responses, we studied 66 Japanese patients who underwent gastroscopy. Using specific enzyme-linked immunosorbent assays, we examined gastric antral mucosal-organ biopsy culture supernatants to assess interleukin-6 (IL-6) and interleukin-8 (IL-8) levels and antibody responses to H. pylori whole-cell antigens CagA, HspA, and HspB. Of the patients studied, 11 were H. pylori negative and 55 were H. pylori positive; by PCR, all strains were cagA(+). As expected, compared to H. pylori-negative patients, H. pylori-positive patients had significantly higher humoral responses to all H. pylori antigens and had higher IL-8 (47.8+/-3.5 versus 10.1+/-4.3 ng/mg of biopsy protein; P<0.001) and IL-6 levels (2.8+/-0.3 versus 0.26+/-0.2 ng/mg of protein; P<0.001). Among the H. pylori-positive patients, supernatant anti-CagA immunoglobulin G (IgG) levels were significantly associated with H. pylori density (P<0.005) and neutrophil infiltration (P<0.005) scores. Anti-CagA immunoglobulin A levels were correlated with intestinal metaplasia (P<0.05). Mononuclear cell infiltration scores were significantly associated with supernatant IL-6 levels (P<0.005) and with IgG responses to whole-cell antigens (P<0.05). Supernatant IL-8 levels were significantly associated with anti-CagA IgG (r = 0.75, P<0.001). Anti-CagA responses correlated with neutrophil infiltration, intestinal metaplasia, H. pylori density, and IL-8 levels, suggesting that the absolute levels of these antibodies may be markers for gastric inflammation and premalignant changes in individual hosts
  276. Ando T; Xu Q; Torres M; Kusugami K; Israel DA; Blaser MJ. "Restriction-modification system differences in Helicobacter pylori are a barrier to interstrain plasmid transfer". Molecular microbiology. 2000 Sep;37(5):1052-1065 (MEDL:10972824 #19043)       

    Helicobacter pylori cells are naturally competent for the uptake of both plasmid and chromosomal DNA. However, we demonstrate that there are strong barriers to transformation of H. pylori strains by plasmids derived from unrelated strains. We sought to determine the molecular mechanisms underlying these barriers. Transformation efficiency was assessed using pHP1, an Escherichia coli-H. pylori shuttle vector conferring kanamycin resistance. Transformation of 33 H. pylori strains was attempted with pHP1 purified from either E. coli or H. pylori, and was successfully introduced into only 11 strains. Digestion of H. pylori chromosomes with different restriction endonucleases (REs) showed that DNA methylation patterns vary substantially among strains. The strain most easily transformed, JP26, was found to have extremely low endogenous RE activity and to lack a restriction-modification (R-M) system, homologous to MboI, which is highly conserved among H. pylori strains. When we introduced this system to JP26, pHP1 from MboI.M+ JP26, but not from wild-type JP26, transformed MboI R-M+ JP26 and heterologous MboI R-M+ wild-type H. pylori strains. Parallel studies with pHP1 from dam+ and dam- E. coli strains confirmed these findings. These data indicate that the endogenous REs of H. pylori strains represent a critical barrier to interstrain plasmid transfer among H. pylori
  277. Blaser MJ. "Linking Helicobacter pylori to gastric cancer". Nature medicine. 2000 Apr;6(4):376-377 (MEDL:10742137 #19050)       
  278. Blaser MJ. "Reply [Letter]". Journal of infectious diseases. 2000 Feb;181(2):806-806 (MEDL:10669388 #19054)       
  279. Donahue JP; Israel DA; Peek RM; Blaser MJ; Miller GG. "Overcoming the restriction barrier to plasmid transformation of Helicobacter pylori". Molecular microbiology. 2000 Sep;37(5):1066-1074 (MEDL:10972825 #19042)       

    Helicobacter pylori strains demonstrate substantial variability in the efficiency of transformation by plasmids from Escherichia coli, and many strains are completely resistant to transformation. Among the barriers to transformation are numerous strain-specific restriction-modification systems in H. pylori. We have developed a method to protect plasmid DNA from restriction by in vitro site-specific methylation using cell-free extracts of H. pylori before transformation. In two cases, plasmid DNA treated with cell-free extracts in vitro acquired the restriction pattern characteristic of genomic DNA from the source strain. Among three strains examined in detail, the transformation frequency by treated plasmid shuttle and suicide vectors was significantly increased compared with mock-treated plasmid DNA. The results indicate that the restriction barrier in H. pylori can be largely overcome by specific DNA methylation in vitro. The approach described should significantly enhance the ability to manipulate gene function in H. pylori and other organisms that have substantial restriction barriers to transformation
  280. Donahue JP; Peek RM; Van Doorn LJ; Thompson SA; Xu Q; Blaser MJ; Miller GG. "Analysis of iceA1 transcription in Helicobacter pylori". Helicobacter. 2000 Mar;5(1):1-12 (MEDL:10672045 #19053)       

    BACKGROUND: Transcription of the Helicobacter pylori iceA1 gene is induced following adherence of the bacterium to gastric epithelial cells in vitro, suggesting that this gene might be involved in H. pylori pathogenesis. Consequently, the current studies were undertaken to characterize iceA1 transcription and to define the structure of iceA1-containing transcripts to evaluate the potential of this gene to encode functional proteins. MATERIALS AND METHODS: Northern blots and primer extension of RNA isolated from broth-grown cultures of various H. pylori strains was done to analyze iceA1-specific gene transcription. Reverse transcriptase (RT)-PCR was used to determine the levels of iceA1 transcripts derived from readthrough transcription that was initiated upstream of iceA1 within the 5'-flanking cysE gene. RESULTS: Three major transcripts were detected and each was initiated from a common promoter, designated PI. Two of these transcripts were comprised of iceA1 sequence, while a third transcript was dicistronic and included the downstream gene, hpyIM. In addition, 10-fold lower levels of iceA1 transcripts were initiated upstream of PI, either within or immediately downstream of cysE. CONCLUSIONS: The present analysis suggests that iceA1 does not encode a functional protein in the majority of H. pylori strains. However, transcription of hpyIM, which encodes a highly conserved DNA adenine methyltransferase, is linked to iceA1 transcription. Therefore, iceA1 may affect H. pylori virulence in vivo through transcriptional regulation of hpyIM expression levels, which may result in specific variations in DNA methylation patterns leading to alteration in the expression of genes involved in virulence or pathogenesis
  281. Falk PG; Syder AJ; Guruge JL; Kirschner D; Blaser MJ; Gordon JI. "Theoretical and experimental approaches for studying factors defining the Helicobacter pylori-host relationship". Trends in microbiology. 2000 Jul;8(7):321-329 (MEDL:10878767 #19045)       

    Mathematical modeling has helped develop hypotheses about the role of microbial and host parameters in the initial and subsequent phases of Helicobacter pylori colonization. Transgenic mice have been used to test the hypothesis that the outcome of colonization is influenced by whether bacteria can adhere to available epithelial cell receptors. Complementary use of modeling and experimental approaches should facilitate studies of H. pylori pathogenesis
  282. Figueiredo C; Quint WG; Sanna R; Sablon E; Donahue JP; Xu Q; Miller GG; Peek RM; Blaser MJ; van Doorn LJ. "Genetic organization and heterogeneity of the iceA locus of Helicobacter pylori". Gene. 2000 Apr 4;246(1-2):59-68 (MEDL:10767527 #19047)       

    The genetic organization and sequence heterogeneity of the iceA locus of Helicobacter pylori was studied, and the existence of two distinct gene families, iceA1 and iceA2, at this locus was confirmed. iceA1 has significant sequence homology to nlaIIIR, encoding an endonuclease in Neisseria lactamica, but the similarity at the protein level is limited, due to frameshift mutations of iceA1 in most H. pylori strains. In only five of the 19 iceA1 strains studied, a full-length open reading frame (ORF), capable of encoding a 228aa protein, with 52% homology to NlaIII was observed. The region upstream of iceA2 is highly variable in length, containing up to 15 copies of 8bp tandem repeats. iceA2 can encode proteins of 24, 59, 94, or 129 amino acids, consisting of 14 and 10aa domains, conserved in all iceA2 strains, flanking 0, 1, 2, or 3 copies of a 35aa cassette. This 35aa cassette consists of domains of 13, 16 and 6aa, respectively. The 13aa and 6aa domains are highly conserved, but the 16aa domain exists in two variants. In total, five distinct iceA2 subtypes were defined. Database searches did not reveal any homologous sequences. Recombinant IceA1 and IceA2 proteins were expressed in Escherichia coli, confirming the predicted ORFs. Genotype-specific PCR primers permitted iceA genotyping in 318 (99. 1%) of a worldwide collection of 321 H. pylori strains. The conserved sizes of the amplification products confirmed the worldwide distribution of discrete variants of iceA1 and iceA2
  283. Figueiredo, C; Quint, W; Megraud, F; Blaser, MJ; van Doorn, L. "Geographic distribution of H-pylori vacA, cagA, and iceA types and subtypes [Meeting Abstract]". Gut: journal of the British Society of Gastroenterology. 2000 OCT;47(4):A20-A20 (ISI:000090131200078 #54408)    
  284. Fujimoto S; Umene K; Saito M; Horikawa K; Blaser MJ. "Restriction fragment length polymorphism analysis using random chromosomal gene probes for epidemiological analysis of Campylobacter jejuni infections". Journal of clinical microbiology. 2000 Apr;38(4):1664-1667 (MEDL:10747164 #19049)    

    We have evaluated the ability of a new genotyping method for Campylobacter jejuni based on restriction fragment length polymorphisms using random chromosomal gene probes. DNAs from C. jejuni strains digested with each of three restriction enzymes, HhaI, HaeIII, and HpaII, were analyzed by Southern hybridization using each of two unrelated cosmid clones, P14 and P15 (respectively containing 30- and 35-kb genomic DNA fragments of C. jejuni strain OH4384). The method reported provides a stable and discriminating means for identifying C. jejuni strains and should be useful for epidemiological analyses
  285. Grogono-Thomas R; Dworkin J; Blaser MJ; Newell DG. "Roles of the surface layer proteins of Campylobacter fetus subsp. fetus in ovine abortion". Infection & immunity. 2000 Mar;68(3):1687-1691 (MEDL:10678989 #19052)       

    The role of the surface (S)-layer proteins of Campylobacter fetus subsp. fetus has been investigated using an ovine model of abortion. Wild-type strain 23D induced abortion in up to 90% of pregnant ewes challenged subcutaneously. Isolates recovered from both dams and fetuses expressed S-layer proteins with variable molecular masses. The spontaneous S-layer-negative variant, strain 23B, neither colonized nor caused abortions in pregnant ewes. A series of isogenic sapA and recA mutants, derived from 23D, also were investigated in this model. A mutant (501 [sapA recA(+)]) caused abortion in one of five challenged animals and was recovered from the placenta of a second animal. Another mutant (502 [sapA recA]) with no S-layer protein expression caused no colonization or abortions in challenged animals but caused abortion when administered intraplacentally. Mutants 600(2) and 600(4), both recA, had fixed expression of 97- and 127-kDa S-layer proteins, respectively. Two of the six animals challenged with mutant 600(4) were colonized, but there were no abortions. As expected, all five strains recovered expressed a 127-kDa S-layer protein. In contrast, mutant 600(2) was recovered from the placentas of all five challenged animals and caused abortion in two. Unexpectedly, one of the 16 isolates expressed a 127-kDa rather than a 97-kDa S-layer protein. Thus, these studies indicate that S-layer proteins appear essential for colonization and/or translocation to the placenta but are not required to mediate fetal injury and that S-layer variation may occur in a recA strain
  286. Haley, CA; D'Agata, EM; Perez-Perez, GI; Blaser, MJ; McGowan, CC. "Association between H-pylori seropositivity and atrophic Gastritis in HIV-infected persons [Meeting Abstract]". Clinical infectious diseases. 2000 JUL;31(1):234-234 (ISI:000088950900170 #54483)    
  287. Harford WV; Barnett C; Lee E; Perez-Perez G; Blaser MJ; Peterson WL. "Acute gastritis with hypochlorhydria: report of 35 cases with long term follow up". Gut: journal of the British Society of Gastroenterology. 2000 Oct;47(4):467-472 (MEDL:10986205 #19040)       

    BACKGROUND: Between 1976 and 1987, 35 cases of acute gastritis with hypochlorhydria (AGH) were seen in our research laboratory. The aims of this study were to determine the natural history of AGH and the role of Helicobacter pylori in its pathogenesis. METHODS: Archived serum and gastric biopsy samples obtained from AGH subjects were examined for evidence of H pylori colonisation. Twenty eight of 33 (85%) surviving AGH subjects returned a mean of 12 years after AGH for follow up studies, including determination of H pylori antibodies, basal and peak acid output, endoscopy, and gastric biopsies. A matched control group underwent the same studies. RESULTS: Archived material provided strong evidence of new H pylori acquisition in a total of 14 subjects within two months, in 18 within four months, and in 22 within 12 months of recognition of AGH. Prevalence of H pylori colonisation at follow up was 82% (23 of 28) in AGH subjects, significantly (p<0.05) higher than in matched controls (29%). Basal and peak acid output returned to pre-AGH levels in all but two subjects. CONCLUSIONS: One of several possible initial manifestations of H pylori acquisition in adults may be AGH. While H pylori colonisation usually persists, hypochlorhydria resolves in most subjects
  288. Israel DA; Lou AS; Blaser MJ. "Characteristics of Helicobacter pylori natural transformation". FEMS microbiology letters. 2000 May 15;186(2):275-280 (MEDL:10802184 #19046)       

    For Helicobacter pylori, which exhibits substantial genetic diversity, many strains are naturally competent for transformation by exogenous DNA. To better understand the mechanism of natural transformation and its role in the generation of diversity, we sought to systematically identify factors important for natural transformation in H. pylori. We now show that the highest frequency of H. pylori transformation occurs when DNA is introduced prior to exponential phase growth, and that it is a saturable phenomenon. That transformation can be inhibited by DNA from Helicobacter (H. pylori and Helicobacter bilis) but not Escherichia coli suggests specificity based on DNA source. Finally, the cag island was determined to be unnecessary for high-frequency transformation
  289. Kato S; Sugiyama T; Kudo M; Ohnuma K; Ozawa K; Iinuma K; Asaka M; Blaser MJ. "CagA antibodies in Japanese children with nodular gastritis or peptic ulcer disease". Journal of clinical microbiology. 2000 Jan;38(1):68-70 (MEDL:10618065 #19056)    

    cagA(+) Helicobacter pylori strains have been linked to more severe gastric inflammation, peptic ulcer disease, and gastric cancer in adults, but there have been few studies of cagA in children. We examined the relationship between H. pylori cagA status and clinical status in Japanese children. Forty H. pylori-positive children were studied: 15 with nodular gastritis, 5 with gastric ulcers, and 20 with duodenal ulcers. H. pylori status was confirmed by biopsy-based tests and serum anti-H. pylori immunoglobulin G (IgG) antibody. As controls, 77 asymptomatic children with sera positive for anti-H. pylori IgG were enrolled. Levels of IgG antibodies to CagA in serum were measured by an antigen-specific enzyme-linked immunosorbent assay. In 16 patients with successful H. pylori eradication, posttreatment levels of CagA and H. pylori IgG antibodies also were studied. The CagA antibody seropositivities of asymptomatic controls (81.8%) and patients with nodular gastritis, gastric ulcers, and duodenal ulcers (80.0 to 95.0%) were not significantly different. Compared with pretreatment levels of CagA antibodies, posttreatment levels decreased progressively and significantly. We conclude that, as in Japanese adults, a high prevalence of cagA(+) H. pylori strains was found in Japanese children, and that there was no association with nodular gastritis or peptic ulcer disease. In the assessment of eradicative therapies, monitoring of serum anti-CagA antibodies does not appear to offer any direct benefit over monitoring of anti-H. pylori antibodies
  290. Kuipers EJ; Israel DA; Kusters JG; Gerrits MM; Weel J; van Der Ende A; van Der Hulst RW; Wirth HP; Hook-Nikanne J; Thompson SA; Blaser MJ. "Quasispecies development of Helicobacter pylori observed in paired isolates obtained years apart from the same host". Journal of infectious diseases. 2000 Jan;181(1):273-282 (MEDL:10608776 #19059)       

    Helicobacter pylori isolates show greater genetic diversity than other bacterial species studied, but the basis for this phenomenon is unknown. Whether detectable genomic mutation appears within an H. pylori population during persistent colonization was investigated. Paired H. pylori populations obtained across 7- to 10-year intervals from 13 patients were characterized by use of methods including polymerase chain reaction (PCR) genotyping for cagA, vacA, iceA, recA, and IS605; random arbitrarily primed DNA (RAPD)-PCR and amplified fragment length polymorphism (AFLP) analysis; and ELISA, to determine Lewis phenotypes. Genotyping, including recA sequence analysis, revealed that initial and follow-up populations represented the same population in 11 patients (85%). Nevertheless, distinct dissimilarities were shown within each of these 11 pairs by both RAPD-PCR and AFLP analyses. During follow-up, Lewis-y levels, but not Lewis-x levels, decreased significantly. The changes detected by RAPD-PCR and AFLP indicate that genetic drift occurs within H. pylori populations over the course of years of colonization of a single host
  291. Legath, AJ; Perez-Perez, GI; Rautelin, H; Kosunen, TU; Blaser, MJ. "Long term stability of serum IgG1/IgG2 antibody ratios to Helicobacter pylori in healthy adults [Meeting Abstract]". Clinical infectious diseases. 2000 JUL;31(1):233-233 (ISI:000088950900169 #54482)    
  292. Legath, AJ; Perez-Perez, GI; Rautelin, H; Kosunen, TU; Peek, RM; Sack, RB; Blaser, MJ. "Serum IgG recognition of Helicobacter pylori antigens after acute acquisition or persistent carriage of the organism [Meeting Abstract]". Clinical infectious diseases. 2000 JUL;31(1):233-233 (ISI:000088950900168 #54481)    
  293. Loffeld RJ; Werdmuller BF; Kuster JG; Perez-Perez GI; Blaser MJ; Kuipers EJ. "Colonization with cagA-positive Helicobacter pylori strains inversely associated with reflux esophagitis and Barrett's esophagus". Digestion. 2000;62(2-3):95-99 (MEDL:11025356 #19035)       

    AIM: The hypothesis that colonization with cagA(+) Helicobacter pylori strains protects against the development of gastroesophageal reflux disease (GERD) and its complications is tested. METHODS: Patients with reflux esophagitis and Barrett's esophagus were studied. Antral biopsy specimens were obtained for detection of H. pylori. A serum sample was obtained for determination of IgG antibodies to H. pylori and to the CagA protein. RESULTS: 736 patients were studied. 118 patients had reflux esophagitis, 36 had Barrett's esophagus, 108 had hiatal hernia without signs of inflammation (the reflux group), and 20 patients had esophageal or stomach cancer. The remaining 454 patients had no signs of GERD. The 262 patients with reflux disease had a significantly lower prevalence of H. pylori (34.9%) than the 454 controls (54.6%; p<0. 001). Among 310 H. pylori-positive patients from whom serum was available, colonization with cagA(+) strains was detected in 59% in the control group versus 35% in the reflux group (p<0.001). Conclusion: Patients with reflux esophagitis and Barrett's esophagus have a significantly lower prevalence of H. pylori colonization than controls, in particular of the cagA(+) type. These data suggest that colonization with cagA(+) H. pylori strains may be protective against the development of GERD
  294. Misawa N; Blaser MJ. "Detection and characterization of autoagglutination activity by Campylobacter jejuni". Infection & immunity. 2000 Nov;68(11):6168-6175 (MEDL:11035721 #19034)       

    In several gram-negative bacterial pathogens, autoagglutination (AAG) activity is a marker for interaction with host cells and virulence. Campylobacter jejuni strains also show AAG, but this property varies considerably among strains. To examine the characteristics of C. jejuni AAG, we developed a quantitative in vitro assay. For strain 81-176, which shows high AAG, activity was optimal for cells grown for < or = 24 h, was independent of growth temperature, and was best measured for cells suspended in phosphate-buffered saline at 25 degrees C for 24 h. AAG activity was heat labile and was abolished by pronase or acid-glycine (pH 2.2) treatment but not by lipase, DNase, or sodium metaperiodate. Strain 4182 has low AAG activity, but extraction with water increased AAG, suggesting the loss of an inhibitor. Strain 6960 has weak AAG with no effect due to water extraction. Our study with clinical isolates suggests that C. jejuni strains may be grouped into three AAG phenotypes. A variant derived from strain 81116 that is flagellate but immotile showed the strong AAG exhibited by the parent strain, suggesting that motility per se is not necessary for the AAG activity. AAG correlated with both bacterial hydrophobicity and adherence to INT407 cells. Mutants which lack flagella (flaA, flaB, and flbA) or common cell surface antigen (peb1A) were constructed in strain 81-176 by natural transformation-mediated allelic exchange. Both AAG activity and bacterial hydrophobicity were abolished in the aflagellate mutants but not the peb1A mutant. In total, these findings indicate that C. jejuni AAG is highly associated with flagellar expression
  295. Nachamkin, Irving; Blaser, Martin J. Campylobacter. Washington DC : ASM Press, 2000. xxiii, 545 p. ; 26cm.   2nd ed    
  296. Nataro, James P; Blaser, Martin J; Cunningham-Rundles, Susanna. Persistent bacterial infections. Washington DC : ACM Press, 2000. xv, 453 p. ; 26cm.     
  297. Peek RM Jr; van Doorn LJ; Donahue JP; Tham KT; Figueiredo C; Blaser MJ; Miller GG. "Quantitative detection of Helicobacter pylori gene expression in vivo and relationship to gastric pathology". Infection & immunity. 2000 Oct;68(10):5488-5495 (MEDL:10992444 #32245)       

    The iceA locus of Helicobacter pylori includes one of two mutually exclusive gene families, iceA1 and iceA2. Colonization with iceA1 strains is associated with enhanced acute mucosal inflammation, and adherence to gastric epithelial cells in vitro induces expression of iceA1 but not iceA2 mRNA; however, both transcripts can be detected in vivo. The aim of this study was to determine whether differing levels of iceA transcription in vivo may contribute to disease pathogenesis. RNA from 41 H. pylori-positive gastric biopsy specimens was reverse transcribed to cDNA. Quantitative PCR was performed using biotinylated iceA1, iceA2, and 16S rRNA primers, and binding of biotinylated products to streptavidin-coated plates was detected by hybridization with a fluorescein-labeled probe. iceA genotypes were determined by PCR and sequence analysis. All 41 samples contained detectable H. pylori 16S rRNA, with similar levels in iceA1- (n = 10) and iceA2 (n = 31)-colonized patients (P = 0.34). Biopsy specimens from four (40%) and 19 (61%) persons colonized with iceA1 or iceA2 strains, respectively, had detectable iceA RNA. Acute inflammatory scores were significantly higher in iceA1 RNA-positive patients than in iceA1 RNA-negative, iceA2 RNA-positive, or iceA2 RNA-negative subjects (P </= 0.05 for each). Within the iceA2 RNA-positive group, H. pylori strains with a single 35-amino-acid cassette were associated with significantly higher mucosal iceA2 transcript levels (P = 0.014 versus strains with two cassettes). These results indicate that the levels of transcription of H. pylori iceA1 and iceA2 and of 16S rRNA are independent and that particular iceA2 gene structures are associated with enhanced transcription. The finding that iceA1 transcription levels are significantly associated with the intensity of neutrophilic infiltration suggests that heterogeneity in inflammatory scores among persons colonized with H. pylori iceA1 strains reflects levels of iceA1 transcription in vivo
  298. Peek RM; Wirth HP; Moss SF; Yang M; Abdalla AM; Tham KT; Zhang T; Tang LH; Modlin IM; Blaser MJ. "Helicobacter pylori alters gastric epithelial cell cycle events and gastrin secretion in Mongolian gerbils". Gastroenterology. 2000 Jan;118(1):48-59 (MEDL:10611153 #19058)       

    BACKGROUND & AIMS: Human colonization with Helicobacter pylori increases the risk for distal gastric adenocarcinoma, possibly by altering gastric epithelial cell cycle events and/or gastrin secretion. This study aimed to determine whether H. pylori virulence-related characteristics affect apoptosis, proliferation, and gastrin levels in a rodent model of gastric adenocarcinoma. METHODS: Mongolian gerbils were challenged with H. pylori wild-type or isogenic cagA(-) and vacA(-) mutants, and apoptotic and proliferating cells were identified by terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate nick-end labeling and proliferating cell nuclear antigen immunohistochemistry, respectively. Serum gastrin levels were determined by radioimmunoassay. RESULTS: Gastric epithelial cell turnover was no different after infection with the wild-type, cagA(-), or vacA(-) strains. H. pylori infection significantly increased antral apoptosis 2-4 weeks after challenge, before apoptotic indices decreased to baseline. In contrast, antral proliferation rates were significantly higher 16-20 weeks after inoculation, but then decreased by 40 weeks. Antral proliferation was significantly related to serum gastrin levels, whereas antral apoptosis was inversely related to acute inflammation and lymphoid follicles. CONCLUSIONS: In H. pylori-infected gerbils, enhanced antral apoptosis is an early and transient cell cycle event. Epithelial cell proliferation peaks later and is significantly related to increased gastrin levels, suggesting that epithelial cell growth in H. pylori-colonized mucosa may be mediated by gastrin-dependent mechanisms
  299. Perez-Perez, GI; Legath, AJ; Rautelin, H; Kosunen, TU; Blaser, MJ. "Long-term stability of serum IgG1/IgG2 antibody ratios to Helicobacter pylori in healthy adults [Meeting Abstract]". Gut: journal of the British Society of Gastroenterology. 2000 OCT;47(4):A35-A36 (ISI:000090131200138 #54409)    
  300. Ray KC; Tu ZC; Grogono-Thomas R; Newell DG; Thompson SA; Blaser MJ. "Campylobacter fetus sap inversion occurs in the absence of RecA function". Infection & immunity. 2000 Oct;68(10):5663-5667 (MEDL:10992468 #19039)       

    Phase variation of Campylobacter fetus surface layer proteins (SLPs) occurs by inversion of a 6.2-kb DNA segment containing the unique sap promoter, permitting expression of a single SLP-encoding gene. Previous work has shown that the C. fetus sap inversion system is RecA dependent. When we challenged a pregnant ewe with a recA mutant of wild-type C. fetus (strain 97-211) that expressed the 97-kDa SLP, 15 of the 16 ovine-passaged isolates expressed the 97-kDa protein. However, one strain (97-209) expressed a 127-kDa SLP, suggesting that chromosomal rearrangement may have occurred to enable SLP switching. Lack of RecA function in strains 97-211 and 97-209 was confirmed by their sensitivity to the DNA-damaging agent methyl methanesulfonate. Southern hybridization and PCR of these strains indicated that the aphA insertion into recA was stably present. However, Southern hybridizations demonstrated that in strain 97-209 inversion had occurred in the sap locus. PCR data confirmed inversion of the 6.2-kb DNA element and indicated that in these recA mutants the sap inversion frequency is reduced by 2 to 3 log(10) units compared to that in the wild type. Thus, although the major sap inversion pathway in C. fetus is RecA dependent, alternative lower-frequency, RecA-independent inversion mechanisms exist
  301. Rothenbacher D; Blaser MJ; Bode G; Brenner H. "Inverse relationship between gastric colonization of Helicobacter pylori and diarrheal illnesses in children: results of a population-based cross-sectional study". Journal of infectious diseases. 2000 Nov;182(5):1446-1449 (MEDL:11015236 #19037)       

    It has been suggested that carriage of Helicobacter pylori may protect against infections by exogenous intestinal pathogens. An analysis was done of all children who were screened for school fitness during 1996-1998 in Ulm, Germany, to compare rates of diarrheal illnesses in H. pylori-positive and H. pylori-negative children. Of 2477 5-8-year-old children studied, 304 (12.3%) were H. pylori-positive by carbon 13-labeled urea breath test. For H. pylori-positive children, diarrhea within the prior 3 months was less often reported than for H. pylori-negative children (54.3% vs. 76.1%; P<.001, adjusted for nationality). Compared with H. pylori-negative children, the odds ratio (OR) for the occurrence of diarrhea within the prior 3 months was 0.37 (95% confidence interval [CI], 0.28-0.49) for H. pylori-positive children; after adjustment for covariates, the OR was 0.56 (95% CI, 0.42-0.76). These data support the hypothesis that H. pylori colonization may protect against diarrheagenic gastrointestinal infections
  302. Rothenbacher, D; Blaser, MJ; Bode, G; Brenner, H. "Doer H. pylori colonization protect from diarrheal illnesses? Results of a population based study in 2477 children [Meeting Abstract]". Clinical infectious diseases. 2000 JUL;31(1):300-300 (ISI:000088950900559 #54486)    
  303. Standaert SM; Yu T; Scott MA; Childs JE; Paddock CD; Nicholson WL; Singleton J; Blaser MJ. "Primary isolation of Ehrlichia chaffeensis from patients with febrile illnesses: clinical and molecular characteristics". Journal of infectious diseases. 2000 Mar;181(3):1082-1088 (MEDL:10720534 #19051)       

    Ehrlichia chaffeensis was sought among patients with a history of tick exposure and fever, and the accuracy of other diagnostic tests was compared with that of primary isolation. Among the 38 patients enrolled, E. chaffeensis was isolated from the blood of 7 (18%) and from cerebrospinal fluid specimens of 2 of these 7. All 7 patients also were positive by polymerase chain reaction (PCR) of blood, and 6 patients developed diagnostic titers of antibody to E. chaffeensis. The isolates were characterized by molecular analysis of the 16S rRNA gene, the 120-kDa protein gene, and the variable-length PCR target (VLPT) of E. chaffeensis. On the basis of the 120-kDa and VLPT genotypes, the cerebrospinal fluid and blood isolates from the same patients were identical. This study demonstrates that both PCR and culture of blood for E. chaffeensis have high diagnostic yields. More frequent isolation of E. chaffeensis from patients with infection should further our understanding of the pathogenesis of this infection
  304. Vaezi MF; Falk GW; Peek RM; Vicari JJ; Goldblum JR; Perez-Perez GI; Rice TW; Blaser MJ; Richter JE. "CagA-positive strains of Helicobacter pylori may protect against Barrett's esophagus". American journal of gastroenterology. 2000 Sep;95(9):2206-2211 (MEDL:11007219 #19038)       

    OBJECTIVE: Helicobacter pylori (H. pylori) colonization is associated with chronic gastritis, peptic ulcer disease, and adenocarcinoma of the distal stomach. However, the role of H. pylori strain variation in complicated gastroesophageal reflux disease, especially Barrett's esophagus, is unknown. Therefore, the aim of this study was to evaluate the prevalence of colonization by cagA+ and cagA- H. pylori strains in the spectrum of gastroesophageal reflux disease, including Barrett's esophagus. METHODS: A total of 251 patients undergoing endoscopy were categorized into four groups: controls, patients with gastroesophageal reflux disease alone, and patients with short- and long-segment Barrett's esophagus. All patients underwent upper endoscopies with biopsies and serum collections. H. pylori and degree of mucosal inflammation in gastric biopsies were assessed and serological assessment made for H. pylori and cagA status. RESULTS: The overall prevalence of H. pylori colonization in the study population was 35% (95% confidence interval = 29.5-41.4%) which did not differ significantly among the groups. However, colonization by cagA+ H. pylori strains was significantly more prevalent among controls (11/25; 44%) and patients with gastroesophageal reflux disease (13/36; 36%) than in patients with short-segment (2/10; 20%) or long-segment Barrett's esophagus (0/18; 0%). Patients with Barrett's esophagus were less likely to be colonized by cagA+ H. pylori strains than reflux patients without Barrett's esophagus (odds ratio = 0.27, 95% confidence interval = 0.11-0.67, p = 0.004). CONCLUSIONS: Colonization by cagA+ H. pylori strains may be protective against the formation of short- and long-segment Barrett's esophagus and its malignant complications
  305. Xu Q; Morgan RD; Roberts RJ; Blaser MJ. "Identification of type II restriction and modification systems in Helicobacter pylori reveals their substantial diversity among strains". Proceedings of the National Academy of Sciences of the United States of America. 2000 Aug 15;97(17):9671-9676 (MEDL:10944229 #19044)       

    A total of 22 type II restriction endonucleases with 18 distinct specificities have been identified in six Helicobacter pylori strains. Among these 18 specificities are three completely new endonucleases, Hpy178III, Hpy99I, and Hpy188I, that specifically cleave DNA at TCNNGA, CGWCG, and TCNGA sites, respectively. The set of endonucleases identified in each strain varies, but all have four- or five-base recognition sequences. Among 16 H. pylori strains, examination of the DNA modification status at the recognition sites of 15 restriction endonucleases reveals that each strain has a substantially different complement of type II modification systems. We conclude that the type II restriction-modification systems in H. pylori are highly diverse between strains, a unique characteristic of H. pylori. The diverse methylation status of H. pylori chromosomal DNA may serve as a new typing system to discriminate H. pylori isolates for epidemiological and clinical purposes. This study also demonstrates that H. pylori is a rich source of type II restriction endonucleases
  306. Xu Q; Stickel S; Roberts RJ; Blaser MJ; Morgan RD. "Purification of the novel endonuclease, Hpy188I, and cloning of its restriction-modification genes reveal evidence of its horizontal transfer to the Helicobacter pylori genome". Journal of biological chemistry. 2000 Jun 2;275(22):17086-17093 (MEDL:10748211 #19048)       

    We have isolated a novel restriction endonuclease, Hpy188I, from Helicobacter pylori strain J188. Hpy188I recognizes the unique sequence, TCNGA, and cleaves the DNA between nucleotides N and G in its recognition sequence to generate a one-base 3' overhang. Cloning and sequence analysis of the Hpy188I modification gene in strain J188 reveal that hpy188IM has a 1299-base pair (bp) open reading frame (ORF) encoding a 432-amino acid product. The predicted protein sequence of M.Hpy188I contains conserved motifs typical of aminomethyltransferases, and Western blotting indicates that it is an N-6 adenine methyltransferase. Downstream of hpy188IM is a 513-bp ORF encoding a 170-amino acid product, that has a 41-bp overlap with hpy188IM. The predicted protein sequence from this ORF matches the amino acid sequence obtained from purified Hpy188I, indicating that it encodes the endonuclease. The Hpy188I R-M genes are not present in either strain of H. pylori that has been completely sequenced but are found in two of 11 H. pylori strains tested. The significantly lower G + C content of the Hpy188I R-M genes implies that they have been introduced relatively recently during the evolution of the H. pylori genome
  307. You WC; Zhang L; Gail MH; Chang YS; Liu WD; Ma JL; Li JY; Jin ML; Hu YR; Yang CS; Blaser MJ; Correa P; Blot WJ; Fraumeni JF; Xu GW. "Gastric dysplasia and gastric cancer: Helicobacter pylori, serum vitamin C, and other risk factors". Journal of the National Cancer Institute. 2000 Oct 4;92(19):1607-1612 (MEDL:11018097 #19036)       

    BACKGROUND: Gastric cancer is generally thought to arise through a series of gastric mucosal changes, but the determinants of the precancerous lesions are not well understood. To identify such determinants, we launched a follow-up study in 1989-1990 among 3433 adults in Linqu County, China, a region with very high rates of gastric cancer. METHODS: Data on cigarette smoking, alcohol consumption, and other characteristics of the participants were obtained by interview in 1989-1990, when an initial endoscopy was taken. At study entry, antibodies to Helicobacter pylori were assayed in 2646 adults (77% of people screened), and levels of serum micronutrients were measured in approximately 450 adults. Follow-up endoscopic and histopathologic examinations were conducted in 1994. Antibodies to H. pylori, levels of serum micronutrients, and other baseline characteristics were compared between subjects whose condition showed progression to dysplasia or gastric cancer from study entry to 1994 and subjects with no change or with regression of their lesions over the same time frame. All P: values are two-sided. RESULTS: The presence of H. pylori at baseline was associated with an increased risk of progression to dysplasia or gastric cancer (odds ratio [OR] = 1.8; 95% confidence interval [CI] = 1.2-2.6). The risk of progression to dysplasia or gastric cancer also was moderately increased with the number of years of cigarette smoking. In contrast, the risk of progression was decreased by 80% (OR = 0.2; 95% CI = 0.1-0.7) among subjects with baseline ascorbic acid levels in the highest tertile compared with those in the lowest tertile, and there was a slightly elevated risk in those individuals with higher levels of alpha-tocopherol. Conclusions: H. pylori infection, cigarette smoking, and low levels of dietary vitamin C may contribute to the progression of precancerous lesions to gastric cancer in this high-risk population
  308. Ando T; Israel DA; Kusugami K; Blaser MJ. "HP0333, a member of the dprA family, is involved in natural transformation in Helicobacter pylori". Journal of bacteriology. 1999 Sep;181(18):5572-5580 (MEDL:10482496 #19064)    

    Helicobacter pylori is naturally competent for DNA transformation, but the mechanism by which transformation occurs is not known. For Haemophilus influenzae, dprA is required for transformation by chromosomal but not plasmid DNA, and the complete genomic sequence of H. pylori 26695 revealed a dprA homolog (HP0333). Examination of genetic databases indicates that DprA homologs are present in a wide variety of bacterial species. To examine whether HP0333 has a function similar to dprA of H. influenzae, HP0333, present in each of 11 strains studied, was disrupted in two H. pylori isolates. For both mutants, the frequency of transformation by H. pylori chromosomal DNA was markedly reduced, but not eliminated, compared to their wild-type parental strains. Mutation of HP0333 also resulted in a marked decrease in transformation frequency by a shuttle plasmid (pHP1), which differs from the phenotype described in H. influenzae. Complementation of the mutant with HP0333 inserted in trans in the chromosomal ureAB locus completely restored the frequency of transformation to that of the wild-type strain. Thus, while dprA is required for high-frequency transformation, transformation also may occur independently of DprA. The presence of DprA homologs in bacteria known not to be naturally competent suggests a broad function in DNA processing
  309. Atherton JC; Cover TL; Twells RJ; Morales MR; Hawkey CJ; Blaser MJ. "Simple and accurate PCR-based system for typing vacuolating cytotoxin alleles of Helicobacter pylori". Journal of clinical microbiology. 1999 Sep;37(9):2979-2982 (MEDL:10449485 #19065)    

    Alleles of the vacuolating cytotoxin gene (vacA) of Helicobacter pylori vary between strains, particularly in the region encoding the signal sequence (which may be type s1 or s2) and the midregion (which may be type m1 or m2). Using a PCR-based typing system developed in the United States, we showed that 36 strains from Asia and South America were all vacA signal sequence type s1; 3 were midregion type m1 and 11 were m2, but 22 could not be typed for the vacA midregion. All strains possessed cagA (cytotoxin-associated gene A), another virulence marker. vacA nucleotide sequence analysis showed that midregion typing failure was due to base substitutions at the primer annealing sites. Using the new sequence data, we developed two new PCR-based vacA midregion typing systems, both of which correctly typed 41 U.S. strains previously typed by the old system and successfully typed all 36 of the non-U.S. strains. All previously untypeable strains were vacA m1, other than one m1/m2 hybrid. In summary, we describe and validate a simple PCR-based system for typing vacuolating cytotoxin (vacA) alleles of H. pylori and show that this system correctly identifies the signal and midregion types of vacA in 77 strains from Asia and North and South America
  310. Atherton JC; Sharp PM; Cover TL; Gonzalez-Valencia G; Peek RM; Thompson SA; Hawkey CJ; Blaser MJ. "Vacuolating cytotoxin (vacA) alleles of Helicobacter pylori comprise two geographically widespread types, m1 and m2, and have evolved through limited recombination". Current microbiology. 1999 Oct;39(4):211-218 (MEDL:10486057 #19063)       

    Vacuolating cytotoxin (vacA) alleles of Helicobacter pylori vary, particularly in their mid region (which may be type m1 or m2) and their signal peptide coding region (type s1 or s2). We investigated nucleotide diversity among vacA alleles in strains from several locales in Asia, South America, and the USA. Phylogenetic analysis of vacA mid region sequences from 18 strains validated the division into two main groups (m1 and m2) and showed further significant divisions within these groups. Informative site analysis demonstrated one example of recombination between m1 and m2 alleles, and several examples of recombination among alleles within these groups. Recombination was not sufficiently extensive to destroy phylogenetic structure entirely. Synonymous nucleotide substitution rates were markedly different between regions of vacA, suggesting different evolutionary divergence times and implying horizontal transfer of genetic elements within vacA. Non-synonymous/synonymous rate ratios were greater between m1 and m2 sequences than among m1 sequences, consistent with m1 and m2 alleles encoding functions fitting strains for slightly different ecological niches
  311. Blaser MJ. "Allelic variation in Helicobacter pylori: progress but no panacea [Comment]". Gut: journal of the British Society of Gastroenterology. 1999 Oct;45(4):477-478 (MEDL:10486346 #19062)       
  312. Blaser MJ. "Hypothesis: the changing relationships of Helicobacter pylori and humans: implications for health and disease". Journal of infectious diseases. 1999 Jun;179(6):1523-1530 (MEDL:10228075 #19072)       

    Helicobacter pylori has apparently colonized the human stomach since time immemorial and is superbly adapted for persistence. Several genotypes, including cag+, are associated with increased risk of gastric and duodenal diseases. With modern life, for probably the first time in human history, there are large numbers of noncolonized persons. Duodenal ulceration has been present essentially for only 200 years; that its incidence rose just as H. pylori was waning is best explained by changes in gastric microecology. As H. pylori is disappearing, duodenal ulceration and gastric cancer rates are falling. However, more proximal diseases, gastroesophageal reflux (GERD), Barrett's esophagus, and adenocarcinomas of the gastric cardia and lower esophagus, are increasing; colonization with cag+ H. pylori strains appears protective against these diseases. Thus, in the 21st century, the continuing decline in H. pylori may lead to the disappearance of duodenal ulcers and distal gastric cancers and toward a marked increase in GERD, Barrett's esophagus, and esophageal adenocarcinoma
  313. Blaser MJ. "In a world of black and white, Helicobacter pylori is gray [Editorial]". Annals of internal medicine. 1999 Apr 20;130(8):695-697 (MEDL:10215569 #19074)    
  314. Blaser MJ. "Prepare for, not create, the future [Letter]". Pharos of Alpha Omega Alpha Honor Medical Society. 1999 Summer;62(3):51-52 (MEDL:10509120 #19061)    
  315. Blaser MJ. "Where does Helicobacter pylori come from and why is it going away? [Comment]". JAMA. 1999 Dec 15;282(23):2260-2262 (MEDL:10605980 #19060)       
  316. Blaser MJ; Kirschner D. "Dynamics of Helicobacter pylori colonization in relation to the host response". Proceedings of the National Academy of Sciences of the United States of America. 1999 Jul 20;96(15):8359-8364 (MEDL:10411880 #19066)       

    The dynamics of Helicobacter pylori colonization from its acquisition through the development of steady-state are examined through a mathematical model that includes the host response. The model encompasses both host and microbiological variation. The individual capacity of the host response is shown to be a key model parameter, leading to either transient or persistent colonization, whereas the growth rate of that response has little effect. Analyses of competing strains indicate that each must occupy a specific niche, otherwise exclusion occurs. The model implies that there exists a lower bound on the host response to the indigenous microflora that is consistent with current biological views of H. pylori. Parallel models may be useful in understanding other persistent host-microbial interactions
  317. Blaser MJ; Kuipers EJ; Ernst P; Axon A; Megraud F. "Panel discussion: breaking the link--clinical options to minimize risk". Alimentary pharmacology & therapeutics. 1999 Mar;13 Suppl 1(8):19-23 (MEDL:10209683 #19075)       
  318. Blaser, Martin J. Helicobacter pylori and gastic cancer. Oxford : Blackwell Science, 1999. 23 p. .
  319. Cover TL; Blaser MJ. "Helicobacter pylori factors associated with disease [Comment]". Gastroenterology. 1999 Jul;117(1):257-261 (MEDL:10381935 #19068)       
  320. Dubois A; Berg DE; Incecik ET; Fiala N; Heman-Ackah LM; Del Valle J; Yang M; Wirth HP; Perez-Perez GI; Blaser MJ. "Host specificity of Helicobacter pylori strains and host responses in experimentally challenged nonhuman primates". Gastroenterology. 1999 Jan;116(1):90-96 (MEDL:9869606 #19077)       

    BACKGROUND & AIMS: The specificity of colonization by Helicobacter pylori and complex host-bacterium interactions cannot be readily examined in humans. The aim of this study was to perform such analyses in rhesus monkeys. METHODS: Four animals that had been cured of natural H. pylori colonization were challenged with a mixture of 7 strains of human origin, and bacteria recovered during periodic videogastroscopy were DNA fingerprinted. RESULTS: Three animals carried mixtures of several strains for 4 months, after which strain J166 predominated. In the fourth animal, only strain J238 was isolated from the earliest phase of colonization through 7 months, but strain J166 again became predominant by 10 months after the challenge. Gastritis scores and plasma gastrin and anti-H. pylori immunoglobulin G titers reached levels observed in naturally colonized animals by 4 months after the challenge; however, no plasma immunoglobulin A response was observed up to 10 months. CONCLUSIONS: These results show that (1) natural colonization does not elicit protective immunity against subsequent H. pylori challenge; (2) individuals differ in susceptibility to different H. pylori strains during initial stages of colonization; and (3) certain strains are better suited than others for long-term survival in different hosts. These observations show the complexity of H. pylori-host interactions
  321. Ng EK; Thompson SA; Perez-Perez GI; Kansau I; van der Ende A; Labigne A; Sung JJ; Chung SC; Blaser MJ. "Helicobacter pylori heat shock protein A: serologic responses and genetic diversity". Clinical & diagnostic laboratory immunology. 1999 May;6(3):377-382 (MEDL:10225839 #19073)    

    Helicobacter pylori synthesizes an unusual GroES homolog, heat shock protein A (HspA). The present study was aimed at an assessment of the serological response to HspA in a group of Chinese patients with defined gastroduodenal pathologies and determination of whether diversity is present in the nucleotide sequences encoding HspA in isolates from these patients. Serum samples collected from 154 patients who had an upper gastrointestinal pathology and the presence of H. pylori defined by biopsy were tested for an immunoglobulin G (IgG) serologic response to H. pylori HspA by an enzyme linked immunosorbant assay. HspA-encoding nucleotide sequences in H. pylori isolates from 14 patients (7 seropositive and 7 seronegative for HspA) were analyzed by PCR and direct sequencing of the PCR products. The sequencing results were compared to those of 48 isolates from other parts of the world. Of the 154 known H. pylori-positive patients, 54 (35.1%) were seropositive for HspA. The A domain (GroES homology) of HspA was highly conserved in the 14 isolates tested. Although the B domain (metal-binding site unique to H. pylori) resembled that in the known major variant, particular amino acid substitutions allowed definition of an HspA variant associated with isolates from East Asia. There were no associations between patient characteristics and HspA seropositivity or amino acid sequences. We confirmed in this study that the clinical outcomes of H. pylori infection are not related to HspA antigenicity or to sequence variation. However, B-domain sequence variation may be a marker for the study of the genetic diversity of H. pylori strains of different geographic origins
  322. Peek RM Jr; Vaezi MF; Falk GW; Goldblum JR; Perez-Perez GI; Richter JE; Blaser MJ. "Role of Helicobacter pylori cagA(+) strains and specific host immune responses on the development of premalignant and malignant lesions in the gastric cardia". International journal of cancer. 1999 Aug 12;82(4):520-524 (MEDL:10404065 #32251)       

    The incidence rates of gastric cardia and esophageal adenocarcinomas are increasing, but data suggest that carriage of cagA(+) Helicobacter pylori strains may protect against development of Barrett's esophagus and esophageal adenocarcinoma. Our aims were to examine the relationship between pre-malignant and malignant lesions in the gastric cardia and serum antibodies to H. pylori antigens in patients with and without complications of Barrett's esophagus. The prevalence of carditis was 40% in controls compared with 13% in patients with complicated or uncomplicated Barrett's esophagus and cardia adenocarcinoma (p < 0.001). Cardia intestinal metaplasia (IM) and atrophy were present and concordant in 28% of controls but less frequent in patients with Barrett's alone or with dysplasia/adenocarcinoma (0% for each, p < 0.001). Carriage of cagA(+) strains was present in 34% of patients with carditis and significantly associated with increased frequency and severity of cardia inflammation, IM, and atrophy but not with adenocarcinoma. IgA and HspA seropositivity were significantly increased in H. pylori-colonized patients with carditis compared to persons with normal cardia histology (p </= 0.005) but not in persons with esophageal disease or cardia adenocarcinoma. We conclude that carriage of cagA(+) H. pylori strains and induction of particular serological responses are significantly associated with marked histological findings in the gastric cardia but not with adenocarcinoma of either the gastric cardia or esophagus
  323. Peek RM; Blaser MJ; Mays DJ; Forsyth MH; Cover TL; Song SY; Krishna U; Pietenpol JA. "Helicobacter pylori strain-specific genotypes and modulation of the gastric epithelial cell cycle". Cancer research. 1999 Dec 15;59(24):6124-6131 (MEDL:10626802 #19055)    

    Helicobacter pylori cag+ strains enhance gastric epithelial cell proliferation and attenuate apoptosis in vivo, which may partially explain the increased risk of gastric cancer associated with these strains. The goals of this study were to identify specific H. pylori genes that regulate epithelial cell cycle events and determine whether these effects were dependent upon p53-mediated pathways. AGS gastric epithelial cells were cultured alone or in the presence of 21 clinical H. pylori isolates, H. pylori reference strain 60190, or its isogenic cagA-, picB-, vacA-, or picB-/vacA- derivatives. Coculture of H. pylori with AGS cells significantly decreased cell viability, an effect most prominent with cag+ strains (P < 0.001 versus cag-strains). cag+ strains significantly increased progression of AGS cells from G1 into G2-M at 6 h and enhanced apoptosis by 72 h. Compared with the parental 60190 strain, the picB- mutant attenuated cell cycle progression at 6 h (P < or = 0.05), and decreased apoptosis with enhanced AGS cell viability at 24 h (P < or = 0.04). The vacA- mutant decreased apoptosis and enhanced viability at later (48-72 h) time points (P < or = 0.05). Compared with the wild-type strain, the picB-/vacA- double mutant markedly attenuated apoptosis and increased cell viability at all time points (P < or = 0.05). Furthermore, cocolonization with H. pylori had no significant effect on expression of p53, p21, and MDM2. The diminished AGS cell viability, progression to G2-M, and apoptosis associated with cag+ H. pylori strains were dependent upon expression of vacA and genes within the cag pathogenicity island. These results may explain heterogeneity in levels of gastric epithelial cell proliferation and apoptosis found within H. pyloricolonized mucosa
  324. Perez-Perez GI; Peek RM; Atherton JC; Blaser MJ; Cover TL. "Detection of anti-VacA antibody responses in serum and gastric juice samples using type s1/m1 and s2/m2 Helicobacter pylori VacA antigens". Clinical & diagnostic laboratory immunology. 1999 Jul;6(4):489-493 (MEDL:10391848 #19067)    

    Several different families of vacuolating toxin (vacA) alleles are present in Helicobacter pylori, and they encode products with differing functional activities. H. pylori strains containing certain types of vacA alleles have been associated with an increased risk for peptic ulcer disease. In this study, we tested serum samples and gastric juice from 19 H. pylori-negative and 39 H. pylori-positive patients for enzyme-linked immunosorbent assay reactivity with two different types of VacA antigens (types s1/m1 and s2/m2), which were purified from H. pylori 60190 and 86-338, respectively. Both antigens were recognized better by serum immunoglobulin G (IgG) from H. pylori-positive persons than by serum IgG from H. pylori-negative persons (P < 0.01). The s1/m1 VacA antigen was better recognized by sera from patients carrying vacA type s1/m1 strains than by sera from patients carrying vacA type s2/m2 or s1/m2 strains (P < 0.01). Conversely, the s2/m2 VacA antigen was better recognized by sera from patients carrying type s2/m2 or s1/m2 strains (P = 0.03). Serum IgG anti-VacA antibodies were present more frequently in patients carrying type s1/m1 strains than in other H. pylori-positive patients (P = 0.0002). In addition, the highest levels of IgA anti-VacA antibodies were detected in the gastric juice of patients carrying type s1/m1 strains. These data indicate that different VacA isoforms have distinct antigenic properties and that multiple forms of VacA elicit antibody responses in H. pylori-positive humans
  325. Van Doorn LJ; Figueiredo C; Megraud F; Pena S; Midolo P; Queiroz DM; Carneiro F; Vanderborght B; Pegado MD; Sanna R; De Boer W; Schneeberger PM; Correa P; Ng EK; Atherton J; Blaser MJ; Quint WG. "Geographic distribution of vacA allelic types of Helicobacter pylori". Gastroenterology. 1999 Apr;116(4):823-830 (MEDL:10092304 #19076)       

    BACKGROUND & AIMS: Distinct allelic types of Helicobacter pylori vacA have been defined. The geographic distribution of vacA alleles and cagA was assessed in this study. METHODS: A total of 735 cultures from patients in 24 countries were analyzed by polymerase chain reaction and reverse hybridization on a line probe assay (LiPA). RESULTS: In 124 (16.9%) of the 735 cultures, multiple vacA genotypes were detected, permitting analysis of 611 strains. In Europe, a distribution gradient of s1 subtypes was observed. In northern and eastern Europe, 89% were subtype s1a. s1a and s1b were equally present in France and Italy, whereas in Spain and Portugal 89% of strains were subtype s1b. s1a and s1b were approximately equally prevalent in North America. In Central and South America, virtually all s1 strains were subtype s1b. Subtype s1c was observed in 77% of the s1 isolates from East Asia. m1 and m2a have equal presence, except on the Iberian peninsula and in Central and South America, where m1 (86.2%) is more prevalent than m2 (13.8%). Subtype m2b was found exclusively among East Asian s1c strains. In all parts of the world, vacA s1/cagA-positive genotypes were associated with peptic ulcer disease (P < 0.001). CONCLUSIONS: These data indicate a geographic distribution of H. pylori genotypes and aid in understanding the relationship of H. pylori with disease
  326. van Doorn LJ; Figueiredo C; Sanna R; Blaser MJ; Quint WG. "Distinct variants of Helicobacter pylori cagA are associated with vacA subtypes". Journal of clinical microbiology. 1999 Jul;37(7):2306-2311 (MEDL:10364602 #19069)    

    The diversity of the cytotoxin-associated gene (cagA) of Helicobacter pylori was analyzed in 45 isolates obtained from nine countries. We examined variation in the 5' end of the cagA open reading frame as determined by PCR and sequencing. Phylogenetic analysis revealed the existence of at least two distinct types of cagA. One variant (cagA1) was found exclusively in strains from Europe, the United States, and Australia, whereas a novel variant (cagA2) was found in strains from East Asia. The greatest diversity between cagA1 and cagA2 was found in the first 20 amino acids of the cagA open reading frame, where several consistent insertions or deletions were observed. Additional cagA sequence variants that could be classified as separate subtypes were found in two of three Peruvian and in five of seven U.S. strains tested. The calculated isoelectric point of the first 154 amino acids of the cagA1 variants (7.52 +/- 1.54) was significantly higher than that of the first 154 amino acids of the cagA2 variants (5.61 +/- 0.94; P < 0.001). Most cagA2 strains contained vacA subtype s1c (P < 0.001), and in vacA m1 strains cagA1 was more frequently observed than cagA2. These results show the epidemiological relationship between cagA and vacA at the subtype level and indicate the existence of distinct H. pylori lineages that are not uniformly distributed over the globe
  327. van Doorn LJ; Verschuuren-van Haperen A; Burnens A; Huysmans M; Vandamme P; Giesendorf BA; Blaser MJ; Quint WG. "Rapid identification of thermotolerant Campylobacter jejuni, Campylobacter coli, Campylobacter lari, and Campylobacter upsaliensis from various geographic locations by a GTPase-based PCR-reverse hybridization assay". Journal of clinical microbiology. 1999 Jun;37(6):1790-1796 (MEDL:10325325 #19070)    

    Recently, a gene from Campylobacter jejuni encoding a putative GTPase was identified. Based on two semiconserved GTP-binding sites encoded within this gene, PCR primers were selected that allow amplification of a 153-bp fragment from C. jejuni, C. coli, C. lari, and C. upsaliensis. Sequence analysis of these PCR products revealed consistent interspecies variation, which allowed the definition of species-specific probes for each of the four thermotolerant Campylobacter species. Multiple probes were used to develop a line probe assay (LiPA) that permits analysis of PCR products by a single reverse hybridization step. A total of 320 reference strains and clinical isolates from various geographic origins were tested by the GTP-based PCR-LiPA. The PCR-LiPA is highly specific in comparison with conventional identification methods, including biochemical and whole-cell protein analyses. In conclusion, a simple method has been developed for rapid and highly specific identification of thermotolerant Campylobacter species
  328. Wassenaar TM; Blaser MJ. "Pathophysiology of Campylobacter jejuni infections of humans". Microbes & infection. 1999 Oct;1(12):1023-1033 (MEDL:10617934 #19057)       

    Campylobacter jejuni and closely related organisms are major causes of human bacterial enteritis. These infections can lead to extraintestinal disease and severe long-term complications. Of these, neurological damage, apparently due to the immune response of the host, is the most striking. This review examines current knowledge of the pathophysiology of the organism. Diversity of C. jejuni isolates in genotypic and phenotypic characteristics now is recognized and clinically relevant examples are presented. Expected future directions are outlined
  329. Wirth HP; Yang M; Peek RM; Hook-Nikanne J; Fried M; Blaser MJ. "Phenotypic diversity in Lewis expression of Helicobacter pylori isolates from the same host". Journal of laboratory & clinical medicine. 1999 May;133(5):488-500 (MEDL:10235132 #19071)       

    Populations of Helicobacter pylori cells show a stable expression of Lewis surface antigens, although phase variation may occur among individual organisms grown in vitro. We searched for variation in Lewis phenotypes among H. pylori cells of minimally in vitro-passaged isolates. Lewis expression in 180 clonal H. pylori populations from the primary culture of 20 gastric biopsy samples from 12 patients, and that in 160 isolates from primary cultures from 16 experimentally infected rodents, were examined by enzyme immunoassays. Substantial differences in Lewis expression were found among the isolates from 9 (75%) of 12 patients. These differences were unrelated to overall genetic diversity as determined by polymerase chain reactions for random amplified polymorphic DNA or cagA status, and they persisted during subsequent in vitro passage. In contrast, Lewis expression was highly uniform in H. pylori isolates from different rodents infected for up to 20 weeks. Variation in H. pylori Lewis expression in genetically closely related organisms in human subjects may provide a pool of bacterial phenotypes for the continuous selection of optimally host-adapted populations suitable for persistence
  330. Abdalla, A M; Sordillo, E M; Hanzely, Z; Perez-Perez, G I; Blaser, M J; Holt, P R; Moss, S F. "Insensitivity of the CLOtest for H. pylori, especially in the elderly [Letter]". Gastroenterology. 1998 Jul;115(1):243-244 (MEDL:9659344 #416852)       
  331. Allos BM; Lippy FT; Carlsen A; Washburn RG; Blaser MJ. "Campylobacter jejuni strains from patients with Guillain-Barre syndrome". Emerging infectious diseases. 1998 Apr-Jun;4(2):263-268 (MEDL:9621196 #19094)    

    Guillain-Barre syndrome (GBS), an acute demyelinating peripheral neuropathy, may be triggered by an acute infectious illness; infection with Campylobacter jejuni is the most frequently reported antecedent event. In Japan, O:19 is the most common serotype among GBS-associated C. jejuni strains. To determine whether serotype O:19 occurs among GBS-associated strains in the United States and Europe, we serotyped seven such strains and found that two (29%) of seven GBS-associated strains from patients in the United States and Germany were serotype O:19. To determine whether GBS-associated strains may be resistant to killing by normal human serum (NHS), we studied the serum susceptibility of 17 GBS- and 27 enteritis-associated strains (including many O:19 and non-O:19 strains) using C. jejuni antibody positive (pool 1) or negative (pool 2) human serum. Using pool 1 serum we found that one (6%) of 18 serotype O:19 strains compared with 11 (42%) of 26 non-O:19 strains were killed; results using pool 2 serum were nearly identical. Finally, 8 O:19 and 8 non-O:19 strains were not significantly different in their ability to bind complement component C3. Serotype O:19 C. jejuni strains were overrepresented among GBS-associated strains in the United States and Germany and were significantly more serum-resistant than non-O:19 strains. The mechanism of this resistance appears unrelated to C3 binding
  332. Ando T; Kusugami K; Ohsuga M; Ina K; Shinoda M; Konagaya T; Sakai T; Imada A; Kasuga N; Nada T; Ichiyama S; Blaser MJ. "Differential normalization of mucosal interleukin-8 and interleukin-6 activity after Helicobacter pylori eradication". Infection & immunity. 1998 Oct;66(10):4742-4747 (MEDL:9746573 #19084)    

    There is differential resolution of mucosal infiltration with neutrophils and mononuclear cells following successful Helicobacter pylori eradication. We investigated the effects of H. pylori eradication on mucosal interleukin-8 (IL-8) and IL-6 activity in relation to the resolution of H. pylori-associated gastritis. Eighty-one duodenal ulcer patients with H. pylori infection received dual- or triple-treatment eradication therapy, and mucosal biopsy specimens obtained at the initial and follow-up endoscopic examinations were cultured in vitro for 24 h. The levels of IL-8 and IL-6 were measured by enzyme-linked immunosorbent assays. In the 42 patients in whom H. pylori eradication failed, there was little change in the numbers of neutrophils and mononuclear cells infiltrating the mucosa and in IL-8 and IL-6 activity. In the 39 patients in whom H. pylori was eradicated, there was normalization both in the numbers of infiltrating neutrophils and in mucosal IL-8 activity, which was evident within 1 month following therapy. In contrast, there was a gradual resolution of mononuclear cell infiltration over a 6-month period, accompanied by a gradual normalization in IL-6 levels. Addition of H. pylori to cultures of mucosal tissues induced a significant increase in IL-8 activity in both uninfected control subjects and patients from whom H. pylori was eradicated. However, this introduction yielded a significant increase in IL-6 activity only in the latter group. This study indicates a dichotomy in the changes of mucosal IL-8 and IL-6 activity after H. pylori eradication. The rapid normalization of IL-8 after H. pylori eradication and the ability of H. pylori cells to stimulate IL-8 in control tissues indicate that IL-8 induction is a part of the innate (nonimmune) responses to this organism. In contrast, the results of experiments analyzing IL-6 activity in cultured mucosal tissues suggest that the gradual resolution of mucosal IL-6 activity and mononuclear infiltration after successful eradication observed in vivo may reflect gradually diminishing residual immune responses against H. pylori
  333. Blaser MJ. "Campylobacter fetus--emerging infection and model system for bacterial pathogenesis at mucosal surfaces [Comment]". Clinical infectious diseases. 1998 Aug;27(2):256-258 (MEDL:9709872 #19085)       
  334. Blaser MJ. "Helicobacter pylori and gastric diseases". British medical journal. BMJ (International ed.). 1998 May 16;316(7143):1507-1510 (MEDL:9582144 #19096)       
  335. Blaser MJ. "Helicobacters and biliary tract disease [Editorial]". Gastroenterology. 1998 Apr;114(4):840-842 (MEDL:9547101 #19100)       
  336. Blaser MJ. "Helicobacters are indigenous to the human stomach: duodenal ulceration is due to changes in gastric microecology in the modern era". Gut: journal of the British Society of Gastroenterology. 1998 Nov;43(5):721-727 (MEDL:9824358 #19080)       
  337. Blaser MJ. "Passover and plague". Perspectives in biology & medicine. 1998 Winter;41(2):243-256 (MEDL:9493401 #19103)    
  338. Blaser, Martin J. "Helicobacter : approaches to a complex organism" IN: Challenges for tomorrow's vaccines [Video Recording]. Rochester NY : University of Rochester Medical Center, 1998. . p.1 video tape-.  (ORIGINAL:0003632 #5272)
  339. Chow WH; Blaser MJ; Blot WJ; Gammon MD; Vaughan TL; Risch HA; Perez-Perez GI; Schoenberg JB; Stanford JL; Rotterdam H; West AB; Fraumeni JF. "An inverse relation between cagA+ strains of Helicobacter pylori infection and risk of esophageal and gastric cardia adenocarcinoma". Cancer research. 1998 Feb 15;58(4):588-590 (MEDL:9485003 #19105)    

    Gastric colonization with Helicobacter pylori, especially cagA+ strains, is a risk factor for noncardia gastric adenocarcinoma, but its relationship with gastric cardia adenocarcinoma is unclear. Although incidence rates for noncardia gastric adenocarcinoma have declined steadily, paralleling a decline in H. pylori prevalence, rates for adenocarcinomas of esophagus and gastric cardia have sharply increased in industrialized countries in recent decades. To clarify the role of H. pylori infection in these tumors with divergent incidence trends, we analyzed serum IgG antibodies to H. pylori and to a recombinant fragment of CagA by antigen-specific ELISA among 129 patients newly diagnosed with esophageal/gastric cardia adenocarcinoma, 67 patients with noncardia gastric adenocarcinoma, and 224 population controls. Cancer risks were estimated by odds ratios (OR) and 95% confidence intervals (CI) using logistic regression models. Infection with cagA+ strains was not significantly related to risk for noncardia gastric cancers (OR, 1.4; CI, 0.7-2.8) but was significantly associated with a reduced risk for esophageal/cardia cancers (OR, 0.4; CI, 0.2-0.8). However, there was little association with cagA- strains of H. pylori for either cancer site (OR, 1.0 and 1.1, respectively). These findings suggest that the effects of H. pylori strains on tumor development vary by anatomical site. Further studies are needed to confirm these results and to assess whether the decreasing prevalence of H. pylori, especially cagA+ strains, may be associated with the rising incidence of esophageal/gastric cardia adenocarcinomas in industrialized countries
  340. Dubois A; Berg DE; Fiala N; Heman-Ackah LM; Perez-Perez GI; Blaser MJ. "Cure of Helicobacter pylori infection by omeprazole-clarithromycin-based therapy in non-human primates". Journal of gastroenterology. 1998 Feb;33(1):18-22 (MEDL:9497216 #19102)       

    Rhesus monkeys raised in colonies tend to become naturally infected by Helicobacter pylori early in life. Earlier attempts to cure H. pylori infection with a 10-day triple therapy (metronidazole, amoxicillin, and peptobismol) were only partially (60%) successful, probably because of preexisting metronidazole resistance. This study was carried out to determine the efficacy of an alternative clarithromycin-omeprazole-based therapy for curing H. pylori infection in Rhesus monkeys (Macaca mulatta), and to examine histologic and serologic correlates of curing. Five monkeys were endoscoped under ketamine anesthesia. Histology and culture of gastric biopsies and serologic tests demonstrated that they were H. pylori-positive. Two animals had not received prior anti-H. pylori treatment, while three other animals had failed triple therapy and carried metronidazole-resistant H. pylori strains. Quadruple therapy with omeprazole, clarithromycin, amoxicillin, and bismuth subsalicylate was given for 10 days to these five animals. All five animals were cured of the infection, and remained H. pylori-free, based on histology and culture at regular intervals for the 5 months posttherapy during which they were followed. Gastritis scores and anti-H. pylori IgG levels decreased in each animal during this period to levels characteristic of uninfected animals. These results indicate that an omeprazole-clarithromycin-based regimen can cure H. pylori infection in Rhesus monkeys, with resolution of abnormal histology and serologic responses. They suggest that this preclinical animal model is useful for testing new anti-H. pylori therapies
  341. Forsyth MH; Atherton JC; Blaser MJ; Cover TL. "Heterogeneity in levels of vacuolating cytotoxin gene (vacA) transcription among Helicobacter pylori strains". Infection & immunity. 1998 Jul;66(7):3088-3094 (MEDL:9632570 #19091)    

    Broth culture supernatants from Tox+ Helicobacter pylori strains induce vacuolation of HeLa cells in vitro and contain VacA in concentrations that are higher than those found in supernatants from Tox- H. pylori strains. To investigate the basis for this phenomenon, we analyzed the transcription of the vacuolating cytotoxin gene (vacA) in eight Tox+ strains (each with a type s1/m1 vacA genotype) and nine Tox- strains (each with a type s2/m2 vacA genotype). Most of the Tox+ and Tox- strains tested used the same vacA transcriptional start point, but Tox+ strains yielded significantly stronger primer extension signal intensities than did Tox- strains (mean densitometry values of 15.8 +/- 1.9 versus 8.9 +/- 1.7, P = 0. 0016). Correspondingly, when we introduced vacA::xylE transcriptional fusions into the chromosomes of a Tox+ strain (60190) and a Tox- strain (86-313), the level of XylE activity in 60190 vacA::xylE was about 30-fold higher than that in 86-313 vacA::xylE. Sequence analysis and promoter exchange experiments indicated that the different levels of vacA transcription in these two strains cannot be explained solely by a difference in promoter strength. These data indicate that Tox+ and Tox- H. pylori strains typically differ not only in the VacA amino acid sequence but also in the level of vacA transcription
  342. Guruge JL; Falk PG; Lorenz RG; Dans M; Wirth HP; Blaser MJ; Berg DE; Gordon JI. "Epithelial attachment alters the outcome of Helicobacter pylori infection". Proceedings of the National Academy of Sciences of the United States of America. 1998 Mar 31;95(7):3925-3930 (MEDL:9520469 #19099)       

    Genetically defined in vivo models are needed to assess the importance of target cell attachment in bacterial pathogenesis. Gastric colonization by Helicobacter pylori in human populations is common and persistent, and has various outcomes including peptic ulcers and cancer. The impact of attachment on the course of infection was examined in transgenic mice expressing a human receptor for H. pylori in their gastric epithelium. Persistent infection by a clinical isolate occurred at comparable microbial densities in transgenic and nontransgenic littermates. However, microbial attachment in transgenic mice resulted in production of autoantibodies to Lewisx carbohydrate epitopes shared by bacteria and acid-secreting parietal cells, chronic gastritis, and parietal cell loss. This model should help identify bacterial and host genes that produce attachment-related pathology
  343. Hook-Nikanne J; Berg DE; Peek RM; Kersulyte D; Tummuru MK; Blaser MJ. "DNA sequence conservation and diversity in transposable element IS605 of Helicobacter pylori". Helicobacter. 1998 Jun;3(2):79-85 (MEDL:9631304 #19092)    

    BACKGROUND: IS605, a transposable element-like sequence identified in the virulence-associated cag region of Helicobacter pylori reference strain NCTC11638, is unusual in containing two oppositely-oriented open reading frames whose products are homologues of the single transposases of the unrelated elements, IS200 and IS1341. METHODS: One hundred independent H. pylori isolates from different parts of the world were screened by PCR and dot blot hybridization to determine the presence of IS605. For some positive isolates, southern hybridizations and sequence analyses were done. RESULTS: Of the 100 isolates, 31 were found to contain sequences related to each ORF with orientation and spacing matching those in canonical IS605-hybridizing sequences. No isolate containing just one ORF and not the other was found. The frequencies of IS605 carriage were independent of geographical origin (U.S. vs. non-U.S.), and of the probable virulence of the isolate (cag status, toxin production or vacA alleles, patient symptoms). Southern blot hybridization of six IS605-containing strains revealed one to nine IS605 copies per genome. Two types of DNA sequence diversity were found: first, a specific 100 bp deletion in two isolates; second, base substitution divergence of 0.4% to 7.5% in pairwise comparisons among the eight isolates characterized, a level of divergence similar to that seen in other H. pylori chromosomal genes. CONCLUSIONS: Based on these findings, we speculate that IS605 is a relatively ancient component of the H. pylori gene pool that has proliferated in this species by horizontal gene transfer, homologous recombination, and transposition
  344. Joiner KA; Powderly WG; Blaser MJ; Klempner MS; Locksley RM; Mandell GL; Preheim LC; Remington JS; Slama TG; Steigbigel NH; Bartlett JG. "Fellowship training in infectious diseases: a report from the regional and national meetings of infectious diseases division chiefs and program directors". Clinical infectious diseases. 1998 May;26(5):1060-1065 (MEDL:9597224 #19097)    

    During the 2-year period April 1995 to April 1997, six regional meetings and one national meeting of division chiefs and program directors of adult infectious diseases programs in the United States were held to review fellowship training. Herein, we report data on job availability and job selection for recently graduated fellows. We summarize discussions on decreasing the number of fellows in training, and we outline suggested components of a core clinical curriculum and of three training tracks--clinician track, clinical investigator track, and basic investigator track
  345. Karita M; Blaser MJ. "Acid-tolerance response in Helicobacter pylori and differences between cagA+ and cagA- strains". Journal of infectious diseases. 1998 Jul;178(1):213-219 (MEDL:9652443 #19088)       

    Helicobacter pylori cagA transcription and translation are maximal at pH 6 in stationary phase. The aim of this study was to determine whether H. pylori has an acid-tolerance response and whether that response is related to CagA expression, by investigating whether preexposure to pH 5 or 6 improved survival of cells subsequently exposed to pH 3. Cell number was determined after broth growth, after exposure to pH 5, 6, or 7, and then after a 30-min exposure to pH 3 without urea. H. pylori cells preexposed to pH 6 or 5 survived pH 3 exposure 100-fold better than did cells preexposed to pH 7. Cells of cagA+ strains grown at pH 6 for 48 h, which induced maximal CagA expression, were significantly more susceptible to pH 3 than were wild type cagA- strains or isogenic cagA- knockouts. Thus, H. pylori strains possess a urea-independent acid-tolerance response. Differential acid susceptibility may contribute to preferential colonization of particular H. pylori strains in specific mucus layer niches
  346. Kuipers EJ; Israel DA; Kusters JG; Blaser MJ. "Evidence for a conjugation-like mechanism of DNA transfer in Helicobacter pylori". Journal of bacteriology. 1998 Jun;180(11):2901-2905 (MEDL:9603879 #19095)    

    Many strains of Helicobacter pylori are naturally competent for transformation in vitro. Since there is a high degree of genetic variation among H. pylori strains, we sought to determine whether mechanisms of DNA exchange other than transformation exist in these organisms. Studies were done with H. pylori cells that each were resistant to two different antibiotics; the procedure used involved mating of cells on plates or in broth, in the absence or presence of DNase. In each experiment, such matings produced progeny with the markers of both parents. Examination of the full resistance profile and random arbitrarily primed DNA PCR (RAPD-PCR) profiles of the progeny indicated that DNA transfer was bidirectional. DNase treatment reduced but did not eliminate transfer; only the presence of both DNase and a membrane separating the cells did so. For progeny derived from matings in the presence of DNase, antibiotic resistance and RAPD profiles indicated that transfer was unidirectional. DNase-treated cell-free supernatants also did not transform, ruling out transduction. These experiments indicate that both a DNase-sensitive mechanism (transformation) and a DNase-resistant conjugation-like mechanism involving cell-to-cell contact may contribute to DNA transfer between H. pylori cells
  347. McGowan CC; Necheva A; Thompson SA; Cover TL; Blaser MJ. "Acid-induced expression of an LPS-associated gene in Helicobacter pylori". Molecular microbiology. 1998 Oct;30(1):19-31 (MEDL:9786182 #19082)       

    To investigate urease-independent mechanisms by which Helicobacter pylori resists acid stress, subtractive RNA hybridization was used to identify H. pylori genes whose expression is induced after exposure to acid pH. This approach led to the isolation of a gene that encoded a predicted 34.8kDa protein (WbcJ), which was homologous to known bacterial O-antigen biosynthesis proteins involved in the conversion of GDP-mannose to GDP-fucose. An isogenic wbcJ null mutant strain failed to express O-antigen and Lewis X or Lewis Y determinants and was more sensitive to acid stress than was the wild-type strain. Qualitative differences in LPS profiles were observed in H. pylori cells grown at pH 5 compared with pH 7, which suggests that H. pylori may alter its LPS structure in response to acidic pH. This may be an important adaptation facilitating H. pylori colonization of the acidic gastric environment
  348. Misawa N; Allos BM; Blaser MJ. "Differentiation of Campylobacter jejuni serotype O19 strains from non-O19 strains by PCR". Journal of clinical microbiology. 1998 Dec;36(12):3567-3573 (MEDL:9817874 #19081)    

    Guillain-Barre syndrome (GBS), a neurologic disease characterized by acute paralysis, is frequently preceded by Campylobacter jejuni infection. Serotype O19 strains are overrepresented among GBS-associated C. jejuni isolates. We previously showed that all O19 strains tested were closely related to one another by randomly amplified polymorphic DNA (RAPD) and restriction fragment length polymorphism analyses. RAPD analysis demonstrated a 1.4-kb band in all O19 strains tested but in no non-O19 strains. We cloned this O19-specific band; nucleotide sequence analysis revealed a truncated open reading frame with significant homology to DNA gyrase subunit B (gyrB) of Helicobacter pylori. PCR using the random primer and a primer specific for gyrB showed that in non-O19 strains, the random primer did not recognize the downstream gyrB binding site. The regions flanking each of the random primer binding sites were amplified by degenerate PCR for further sequencing. Although the random primer had several mismatches with the downstream gyrB binding site, a single nucleotide polymorphism 6 bp upstream from the 3' terminus was found to distinguish O19 and non-O19 strains. PCR using 3'-mismatched primers based on this polymorphism was designed to differentiate O19 strains from non-O19 strains. When a total of 42 (18 O19 and 24 non-O19) strains from five different countries were examined, O19 strains were distinguishable from non-O19 strains in each case. This PCR method should permit identification of O19 C. jejuni strains
  349. Monteiro MA; Chan KH; Rasko DA; Taylor DE; Zheng PY; Appelmelk BJ; Wirth HP; Yang M; Blaser MJ; Hynes SO; Moran AP; Perry MB. "Simultaneous expression of type 1 and type 2 Lewis blood group antigens by Helicobacter pylori lipopolysaccharides. Molecular mimicry between h. pylori lipopolysaccharides and human gastric epithelial cell surface glycoforms". Journal of biological chemistry. 1998 May 8;273(19):11533-11543 (MEDL:9565568 #19093)       

    Previous structural investigations performed on the lipopolysaccharides (LPSs) from the human gastric pathogen Helicobacter pylori have revealed that these cell surface glycan molecules express type 2 partially fucosylated, glucosylated, or galactosylated N-acetyllactosamine O antigen chains (O-chains) of various lengths, which may or may not be terminated at the nonreducing end by Lewis X (Lex) and/or Ley blood group epitopes in mimicry of human cell surface glycoconjugates and glycolipids. Subsequently, serological experiments with commercially available Lewis-specific monoclonal antibodies also have recognized the presence of Lex and Ley blood group antigens in H. pylori but, in addition, have indicated the presence of type 1 chain Lea, Leb, and Led (H-type 1) blood group epitopes in some H. pylori strains. To confirm their presence, structural studies and additional serological experiments were undertaken on H. pylori strains suspected of carrying type 1 chain epitopes. These investigations revealed that the O-chain region of H. pylori strain UA948 carried both Lea (type 1) and Lex (type 2) blood group determinants. The O-chain from H. pylori UA955 LPS expressed the terminal Lewis disaccharide (type 1 chain) and Lex and Ley antigens (type 2). The O-chain of H. pylori J223 LPS carried the type 1 chain precursor Lec, the H-1 epitope (Led, type 1 chain) and an elongated nonfucosylated type 2 N-acetyllactosamine chain (i antigen). Thus, O-chains from H. pylori LPSs can also express fucosylated type 1 sequences, and the LPS from a single H. pylori strain may carry O-chains with type 1 and 2 Lewis blood groups simultaneously. That monoclonal antibodies putatively specific for the Leb determinant can detect glycan substructures (Le disaccharide, Lec, and Led) of Leb indicates their nonspecificity. The expression of both type 1 and 2 Lewis antigens by H. pylori LPSs mimics the cell surface glycomolecules present in both the gastric superficial (which expresses mainly type 1 determinants) and the superficial and glandular epithelium regions (both of which express predominantly type 2 determinants). Therefore, each H. pylori strain may have a different niche within the gastric mucosa, and each individual LPS blood group antigen may have a dissimilar role in H. pylori adaptation
  350. Peek RM; Thompson SA; Donahue JP; Tham KT; Atherton JC; Blaser MJ; Miller GG. "Adherence to gastric epithelial cells induces expression of a Helicobacter pylori gene, iceA, that is associated with clinical outcome". Proceedings of the Association of American Physicians. 1998 Nov-Dec;110(6):531-544 (MEDL:9824536 #19079)    

    Most persons infected with Helicobacter pylori strains that produce vacuolating cytotoxin and possess cytotoxin-associated gene A (cagA) genotype nonetheless remain asymptomatic, suggesting that additional genes are important in virulence. We hypothesized that adherence to gastric epithelium provides stimuli that induce expression of some virulence genes. Our aims were to identify expression of H. pylori genes induced by adherence and to determine if such genes were correlated with peptic ulceration, mucosal interleukin-8 (IL-8) levels, and gastric inflammation. RNA was isolated from an ulcer-derived strain and a gastritis-derived strain that were exposed or not exposed to gastric epithelial cells. These RNAs were used for random arbitrarily primed reverse transcription polymerase chain reaction to identify newly expressed transcripts unique to the ulcer-derived strain following adherence. Clinical isolates of H. pylori were characterized for presence of the newly identified gene, and mucosal IL-8 and inflammation were examined in gastric biopsies from the source patients. A novel H. pylori gene, iceA (induced by contact with epithelium), was identified. DNA sequences revealed two families, iceA1 and iceA2. iceA1 strains were significantly associated with peptic ulceration and increased mucosal concentrations of IL-8. Both iceA1 and iceA2 were expressed in vivo by respective H. pylori strains in gastric biopsies. Adherence to gastric epithelial cells in vitro stimulates the transcription of iceA1, an H. pylori gene that is highly correlated with pathological outcome
  351. Pei Z; Burucoa C; Grignon B; Baqar S; Huang XZ; Kopecko DJ; Bourgeois AL; Fauchere JL; Blaser MJ. "Mutation in the peb1A locus of Campylobacter jejuni reduces interactions with epithelial cells and intestinal colonization of mice". Infection & immunity. 1998 Mar;66(3):938-943 (MEDL:9488379 #19104)    

    Campylobacter jejuni is one of the leading causes of bacterial diarrhea throughout the world. We previously found that PEB1 is a homolog of cluster 3 binding proteins of bacterial ABC transporters and that a C. jejuni adhesin, cell-binding factor 1 (CBF1), if not identical to, contains PEB1. A single protein migrating at approximately 27 to 28 kDa was recognized by anti-CBF1 and anti-PEB1. To determine the role that the operon encoding PEB1 plays in C. jejuni adherence, peb1A, the gene encoding PEB1, was disrupted in strain 81-176 by insertion of a kanamycin resistance gene through homologous recombination. Inactivation of this operon completely abolished expression of CBF1, as determined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and immunoblotting. In comparison to the wild-type strain, the mutant strain showed 50- to 100-fold less adherence to and 15-fold less invasion of epithelial cells in culture. Mouse challenge studies showed that the rate and duration of intestinal colonization by the mutant were significantly lower and shorter than with the wild-type strain. In summary, PEB1 is identical to a previously identified cell-binding factor, CBF1, in C. jejuni, and the peb1A locus plays an important role in epithelial cell interactions and in intestinal colonization in a mouse model
  352. Romano M; Ricci V; Di Popolo A; Sommi P; Del Vecchio Blanco C; Bruni CB; Ventura U; Cover TL; Blaser MJ; Coffey RJ; Zarrilli R. "Helicobacter pylori upregulates expression of epidermal growth factor-related peptides, but inhibits their proliferative effect in MKN 28 gastric mucosal cells". Journal of clinical investigation. 1998 Apr 15;101(8):1604-1613 (MEDL:9541490 #19098)       

    Acute exposure to Helicobacter pylori causes cell damage and impairs the processes of cell migration and proliferation in cultured gastric mucosal cells in vitro. EGF-related growth factors play a major role in protecting gastric mucosa against injury, and are involved in the process of gastric mucosal healing. We therefore studied the acute effect of H. pylori on expression of EGF-related growth factors and the proliferative response to these factors in gastric mucosal cells (MKN 28) derived from gastric adenocarcinoma. Exposure of MKN 28 cells to H. pylori suspensions or broth culture filtrates upregulated mRNA expression of amphiregulin (AR) and heparin-binding EGF-like growth factor (HB-EGF), but not TGFalpha. This effect was specifically related to H. pylori since it was not observed with E. coli, and was independent of VacA, CagA, PicA, PicB, or ammonia. Moreover, H. pylori broth culture filtrates stimulated extracellular release of AR and HB-EGF protein by MKN 28 cells. AR and HB-EGF dose-dependently and significantly stimulated proliferation of MKN 28 cells in the absence of H. pylori filtrate, but had no effect in the presence of H. pylori broth culture filtrates. Inhibition of AR- or HB-EGF- induced stimulation of cell growth was not mediated by downregulation of the EGF receptor since EGF receptor protein levels, EGF binding affinity, number of specific binding sites for EGF, or HB-EGF- or AR-dependent tyrosine phosphorylation of the EGF receptor were not significantly altered by incubation with H. pylori broth culture filtrates. Increased expression of AR and HB-EGF were mediated by an H. pylori factor > 12 kD in size, whereas antiproliferative effects were mediated by both VacA and a factor < 12 kD in size. We conclude that H. pylori increases mucosal generation of EGF-related peptides, but in this acute experimental model, this event is not able to counteract the inhibitory effect of H. pylori on cell growth. The inhibitory effect of H. pylori on the reparative events mediated by EGF-related growth factors might play a role in the pathogenesis of H. pylori-induced gastroduodenal injury
  353. Sharma SA; Tummuru MK; Blaser MJ; Kerr LD. "Activation of IL-8 gene expression by Helicobacter pylori is regulated by transcription factor nuclear factor-kappa B in gastric epithelial cells". Journal of immunology. 1998 Mar 1;160(5):2401-2407 (MEDL:9498783 #19101)    

    In vivo, gastric infection with Helicobacter pylori leads to substantial production of the inflammatory cytokines IL-1, IL-6, TNF-alpha, and IL-8. H. pylori strains that contain the cag pathogenicity island (cag+) and are associated with ulceration and gastric carcinoma induce greater cytokine production than cag- strains. Expression of these cytokines is often regulated by the transcription factor complex, nuclear factor-kappa B (NF-kappa B) through kappa B-binding elements in the enhancer/promoter regions of their genes. We report that more virulent cag+ H. pylori strains induce increased NF-kappa B-DNA binding activity, which elevates IL-8 expression in AGS gastric epithelial cells. The cag+ H. pylori strains induce significant stimulation of IL-8 promoter-driven reporter activity, while cag- strains do not. Furthermore, mutation of specific genes within the cag island (picA1 and picB) ablates enhanced NF-kappa B activation and IL-8 transcription. Increased IL-8 expression is inhibited by mutation in either the NF-kappa B or NF-IL-6 binding element. The cag+ strains, compared with the cag- strains, induce enhanced nuclear localization of a RelA-containing NF-kappa B binding complex, but no increase in NF-IL-6 binding activity. These studies demonstrate that the ability of different types of H. pylori strains to activate NF-kappa B correlates with their ability to induce IL-8 transcription and indicate a mechanism for the heightened inflammatory response seen in subjects infected with cag+ H. pylori strains
  354. Sipponen P; Hyvarinen H; Seppala K; Blaser MJ. "Review article: Pathogenesis of the transformation from gastritis to malignancy". Alimentary pharmacology & therapeutics. 1998 Feb;12 Suppl 1(9):61-71 (MEDL:9701004 #19087)       

    Helicobacter pylori acquisition is the main cause of chronic gastritis in humans. In up to half of the infected subjects, chronic gastritis progresses to atrophic gastritis and intestinal metaplasia. During this course, various mechanisms are triggered that may contribute to the pathogenesis of gastric cancer. Such mechanisms include the inflammation-related cascades of cytokine and free radical reactions, up- and downregulation of growth factors and their receptors, and the atrophy-related impairment of acid output and intraluminal acidity. An array of other factors may also have become significant including overgrowth of bacteria other than H. pylori in the hypochlorhydric or achlorhydric stomach, a high dietary consumption of salt, nitrate, or nitrite, smoking, deficiency of vitamins or micronutrients, influence of sex hormones, or an inherited liability of the dividing epithelial cells to gene errors. These factors may vary in effect between populations and individuals but, if active, may affect the cell genome which may further influence the course and progression of chronic gastritis, and can finally result in overt gastric neoplasia. The molecular biology of gastric cancer has revealed a spectrum of gene errors which vary in type and extent between different histological types of cancer, and between individual cases. There now is evidence that the intestinal metaplasia or the gastric epithelium in atrophic gastritis reveal signs of abnormal expression of various regulatory genes well before the appearance of gastric neoplasia. It is possible that the mechanisms leading to mutation of the genes in epithelial cells are triggered very early in the H. pylori gastritis cascade, and that atrophic gastritis and intestinal metaplasia result from these processes
  355. Thompson SA; Shedd OL; Ray KC; Beins MH; Jorgensen JP; Blaser MJ. "Campylobacter fetus surface layer proteins are transported by a type I secretion system". Journal of bacteriology. 1998 Dec;180(24):6450-6458 (MEDL:9851986 #19078)    

    The virulence of Campylobacter fetus, a bacterial pathogen of ungulates and humans, is mediated in part by the presence of a paracrystalline surface layer (S-layer) that confers serum resistance. The subunits of the S-layer are S-layer proteins (SLPs) that are secreted in the absence of an N-terminal signal sequence and attach to either type A or B C. fetus lipopolysaccharide in a serospecific manner. Antigenic variation of multiple SLPs (encoded by sapA homologs) of type A strain 23D occurs by inversion of a promoter-containing DNA element flanked by two sapA homologs. Cloning and sequencing of the entire 6.2-kb invertible region from C. fetus 23D revealed a probable 5.6-kb operon of four overlapping genes (sapCDEF, with sizes of 1,035, 1,752, 1,284, and 1,302 bp, respectively) transcribed in the opposite direction from sapA. The four genes also were present in the invertible region of type B strain 84-107 and were virtually identical to their counterparts in the type A strain. Although SapC had no database homologies, SapD, SapE, and SapF had predicted amino acid homologies with type I protein secretion systems (typified by Escherichia coli HlyBD/TolC or Erwinia chrysanthemi PrtDEF) that utilize C-terminal secretion signals to mediate the secretion of hemolysins, leukotoxins, or proteases from other bacterial species. Analysis of the C termini of four C. fetus SLPs revealed conserved structures that are potential secretion signals. A C. fetus sapD mutant neither produced nor secreted SLPs. E. coli expressing C. fetus sapA and sapCDEF secreted SapA, indicating that the sapCDEF genes are sufficient for SLP secretion. C. fetus SLPs therefore are transported to the cell surface by a type I secretion system
  356. van Doorn LJ; Figueiredo C; Sanna R; Pena S; Midolo P; Ng EK; Atherton JC; Blaser MJ; Quint WG. "Expanding allelic diversity of Helicobacter pylori vacA". Journal of clinical microbiology. 1998 Sep;36(9):2597-2603 (MEDL:9705399 #19086)    

    The diversity of the gene encoding the vacuolating cytotoxin (vacA) of Helicobacter pylori was analyzed in 98 isolates obtained from different geographic locations. The studies focused on variation in the previously defined s and m regions of vacA, as determined by PCR and direct sequencing. Phylogenetic analysis revealed the existence of four distinct types of s-region alleles: aside from the previously described s1a, s1b, and s2 allelic types, a novel subtype, designated s1c, was found. Subtype s1c was observed exclusively in isolates from East Asia and appears to be the major s1 allele in that part of the world. Three different allelic forms (m1, m2a, and m2b) were detected in the m region. On the basis of sequence alignments, universal PCR primers that allow effective amplification of the s and m regions from H. pylori isolates from all over the world were defined. Amplimers were subsequently analyzed by reverse hybridization onto a line probe assay (LiPA) that allows the simultaneous and highly specific hybridization of the different vacA s- and m-region alleles and tests for the presence of the cytotoxin-associated gene (cagA). This PCR-LiPA method permits rapid analysis of the vacA and cagA status of H. pylori strains for clinical and epidemiological studies and will facilitate identification of any further variations
  357. Vicari JJ; Peek RM; Falk GW; Goldblum JR; Easley KA; Schnell J; Perez-Perez GI; Halter SA; Rice TW; Blaser MJ; Richter JE. "The seroprevalence of cagA-positive Helicobacter pylori strains in the spectrum of gastroesophageal reflux disease". Gastroenterology. 1998 Jul;115(1):50-57 (MEDL:9649458 #19090)       

    BACKGROUND & AIMS: The role of Helicobacter pylori in the pathogenesis of gastroesophageal reflux disease (GERD) is unknown. We determined the prevalence of cagA-positive (cagA+) H. pylori strains in patients with GERD or its complications compared with controls of similar age. METHODS: A total of 153 consecutive patients with GERD, Barrett's esophagus, and Barrett's esophagus complicated by dysplasia or adenocarcinoma were compared with 57 controls who underwent upper endoscopy for reasons other than GERD. H. pylori infection and CagA antibody status were determined by histology and enzyme-linked immunosorbent assay. RESULTS: H. pylori prevalence was lower (34%) in patients with GERD and its sequelae than in the control group (45.6%)(P = 0.15). Regardless of the group, increasing age was associated with higher prevalence of H. pylori (P = 0.003). When compared with controls (42.3%), the prevalence of cagA+ H. pylori strains decreased (P = 0.008) in patients with more severe complications of GERD (GERD, 36.7% [nonerosive GERD, 41.2%; erosive GERD, 30.8%]; Barrett's esophagus, 13.3%; and Barrett's with adenocarcinoma/dysplasia, 0%). CONCLUSIONS: Prevalence of H. pylori in patients with GERD and its sequelae was lower but not significantly different than that of a control group. However, patients carrying cagA+ strains of H. pylori may be protected against the complications of GERD, especially Barrett's esophagus and its associated dysplasia and adenocarcinoma
  358. Wirth HP; Beins MH; Yang M; Tham KT; Blaser MJ. "Experimental infection of Mongolian gerbils with wild-type and mutant Helicobacter pylori strains". Infection & immunity. 1998 Oct;66(10):4856-4866 (MEDL:9746590 #19083)    

    Experimental Helicobacter pylori infection was studied in Mongolian gerbils with fresh human isolates that carry or do not carry cagA (cagA-positive or cagA-negative, respectively), multiply passaged laboratory strains, wild-type strain G1.1, or isogenic ureA, cagA, or vacA mutants of G1.1. Animals were sacrificed 1 to 32 weeks after challenge, the stomach was removed from each animal for quantitative culture, urease test, and histologic testing, and blood was collected for antibody determinations. No colonization occurred after >/=20 in vitro passages of wild-type strain G1.1 or with the ureA mutant of G1.1. In contrast, infection occurred in animals challenged with wild-type G1.1 (99 of 101 animals) or the cagA (25 of 25) or vacA (25 of 29) mutant of G1.1. Infection with G1.1 persisted for at least 8 months. All 15 animals challenged with any of three fresh human cagA-positive isolates became infected, in contrast to only 6 (23%) of 26 animals challenged with one of four fresh human cagA-negative isolates (P < 0.001). Similar to infection in humans, H. pylori colonization of gerbils induced gastric inflammation and a systemic antibody response to H. pylori antigens. These data confirm the utility of gerbils as an animal model of H. pylori infection and indicate the importance of bacterial strain characteristics for successful infection
  359. Atherton JC; Peek RM; Tham KT; Cover TL; Blaser MJ. "Clinical and pathological importance of heterogeneity in vacA, the vacuolating cytotoxin gene of Helicobacter pylori". Gastroenterology. 1997 Jan;112(1):92-99 (MEDL:8978347 #19138)       

    BACKGROUND & AIMS: vacA encodes the vacuolating cytotoxin of Helicobacter pylori and exhibits marked variation in signal sequence and midgene coding regions. The implications for gastroduodenal pathology are unknown. The aim of this study was to define the association of vacA genotype with gastric inflammation and injury, in vitro cytotoxin activity, and peptic ulceration. METHODS: Sixty-one consecutive dyspeptic patients underwent endoscopy and gastric biopsy. The biopsy specimens were processed for H. pylori culture, and 52 specimens were also processed for histology. H. pylori vacA was typed by polymerase chain reaction and colony hybridization. Cytotoxin activity was assessed by a HeLa cell vacuolation assay. RESULTS: vacA signal sequence type s1a strains were associated with greater antral mucosal neutrophil and lymphocyte infiltration than s1b or s2 strains (P < 0.05). vacA midregion type m1 strains were associated with greater gastric epithelial damage than m2 strains (P < 0.05). Both midregion and signal sequence were associated with cytotoxin activity in vitro. Duodenal ulcer disease occurred in 89% of 18 patients with s1a strains vs. 29% of 14 with s1b strains (P < 0.01), 20% of 10 with s2 strains (P < 0.001), and 16% of 19 uninfected patients (P < 0.001). CONCLUSIONS: H. pylori strains of vacA signal sequence type s1a are associated with enhanced gastric inflammation and duodenal ulceration. vacA s2 strains are associated with less inflammation and lower ulcer prevalence
  360. Bahl H; Scholz H; Bayan N; Chami M; Leblon G; Gulik-Krzywicki T; Shechter E; Fouet A; Mesnage S; Tosi-Couture E; Gounon P; Mock M; Conway de Macario E; Macario AJ; Fernandez-Herrero LA; Olabarria G; Berenguer J; Blaser MJ; Kuen B; Lubitz W; Sara M; Pouwels PH; Kolen CP; Boot HJ; Resch S. "Molecular biology of S-layers". FEMS microbiology reviews. 1997 Jun;20(1-2):47-98 (MEDL:9276928 #19129)       

    In this chapter we report on the molecular biology of crystalline surface layers of different bacterial groups. The limited information indicates that there are many variations on a common theme. Sequence variety, antigenic diversity, gene expression, rearrangements, influence of environmental factors and applied aspects are addressed. There is considerable variety in the S-layer composition, which was elucidated by sequence analysis of the corresponding genes. In Corynebacterium glutamicum one major cell wall protein is responsible for the formation of a highly ordered, hexagonal array. In contrast, two abundant surface proteins from the S-layer of Bacillus anthracis. Each protein possesses three S-layer homology motifs and one protein could be a virulence factor. The antigenic diversity and ABC transporters are important features, which have been studied in methanogenic archaea. The expression of the S-layer components is controlled by three genes in the case of Thermus thermophilus. One has repressor activity on the S-layer gene promoter, the second codes for the S-layer protein. The rearrangement by reciprocal recombination was investigated in Campylobacter fetus. 7-8 S-layer proteins with a high degree of homology at the 5' and 3' ends were found. Environmental changes influence the surface properties of Bacillus stearothermophilus. Depending on oxygen supply, this species produces different S-layer proteins. Finally, the molecular bases for some applications are discussed. Recombinant S-layer fusion proteins have been designed for biotechnology
  361. Beales I; Blaser MJ; Srinivasan S; Calam J; Perez-Perez GI; Yamada T; Scheiman J; Post L; Del Valle J. "Effect of Helicobacter pylori products and recombinant cytokines on gastrin release from cultured canine G cells". Gastroenterology. 1997 Aug;113(2):465-471 (MEDL:9247465 #19122)       

    BACKGROUND & AIMS: The pathophysiology of hypergastrinemia in Helicobacter pylori infection is undefined, but the infected antrum shows a marked inflammatory response with local production of cytokines. Hypergastrinemia and inflammatory infiltrate clear with successful eradication. The aim of this study was to examine whether the cytokines tumor necrosis factor alpha or interleukin 8 (IL-8), which are produced in the gastric mucosa of patients with H. pylori-induced peptic disease or H. pylori products, can stimulate gastrin release from isolated cultured canine G cells. METHODS: Canine G cells were isolated by collagenase digestion, enriched by centrifugal elutriation, incubated with cytokines, bacterial components, or both, and gastrin release was measured by radioimmunoassay. RESULTS: IL-8 (1 and 10 nmol/L) stimulated gastrin release by 34% +/- 13% and 43% +/- 23% (P < 0.05) above basal, respectively. H. pylori sonicates, water extract preparations, and lipopolysaccharide had no stimulatory actions, but the sonicates from two of four strains potentiated the effects of IL-8, leading to maximal gastrin release of 230% +/- 130% and 232% +/- 33% above basal, respectively (P < 0.05). CONCLUSIONS: IL-8 stimulated gastrin release from isolated G cells, and the effect was potentiated by H. pylori products. The interaction of cytokines and H. pylori may contribute to the hypergastrinemia seen in vivo
  362. Blaser MJ. "Ecology of Helicobacter pylori in the human stomach". Journal of clinical investigation. 1997 Aug 15;100(4):759-762 (MEDL:9259572 #19121)       
  363. Blaser MJ. "Epidemiologic and clinical features of Campylobacter jejuni infections". Journal of infectious diseases. 1997 Dec;176 Suppl 2(1):S103-S105 (MEDL:9396691 #19110)       

    Gram-negative bacteria of the genus Campylobacter and of related genera frequently colonize the gastrointestinal tracts of humans, other mammals, and birds. One organism, Campylobacter jejuni, has been recognized as an important human pathogen, usually causing a diarrheal illness. Infection is common throughout the world, but clinical and epidemiologic features differ in developed and developing countries. The high incidence of C. jejuni infections and their propensity to invade tissue and to induce inflammation are compatible with a role in the causation of Guillain-Barre syndrome
  364. Blaser MJ. "Helicobacter pylori eradication and its implications for the future". Alimentary pharmacology & therapeutics. 1997 Apr;11 Suppl 1(9057):103-107 (MEDL:9146796 #19134)       

    It has become evident that at least some strains of Helicobacter pylori are pathogenic for humans. However, H. pylori are highly diverse and at least part of this variation involves characteristics related to pathogenicity. A large amount of evidence suggests that H. pylori infection of humans is ancient, and in general, the interaction is not terribly destructive. However, we should try to understand better the risks associated with infection with particular H. pylori strains, and limit treatment to those situations in which the indications for eradicating H. pylori are clear-cut. It is entirely possible that some H. pylori strains are commensals, and that others are symbionts. Eradicating those infections could ultimately cause more harm than good. It is too early to reach firm conclusions about whether all H. pylori infections need to be eradicated
  365. Blaser MJ. "Heterogeneity of Helicobacter pylori". European journal of gastroenterology & hepatology. 1997 Apr;9 Suppl 1(9057):S3-6; discussion S6 (MEDL:9160209 #19133)    

    Although many physicians view Helicobacter pylori strains as a homogenous group of organisms, it has become increasingly clear that populations in humans are highly diverse. This heterogeneity can be analyzed at two different levels: genotypic variation among strains and variations in H. pylori populations within an individual host. Genotypic variation includes point mutations in conserved genes (e.g. ureC), variation in the gene order on physical maps, mosaicism in conserved genes (e.g. vacAs1a), non-conserved genes (e.g. cagA) and extragenetic elements (e.g. IS605). Population differences include the observations that humans can be simultaneously infected with two or more H. pylori strains and that a single strain may represent a cluster of closely related organisms (a 'quasispecies'). The presence of multiple organisms within a host may occur as a result of recombination events leading to genetic shift, whereas ongoing mutation within a strain can lead to the formation of quasispecies by genetic drift. Over recent years it has become increasingly clear that observations on the fundamental biology of H. pylori have considerable clinical relevance. Several genotypic markers (e.g. cagA, vacA, sIa and iceA1) are associated with an increased risk of disease. Also, the multiplicity of infection and quasispecies indicates that analysis of a single H. pylori isolate is inaccurate for defining the genotype of H. pylori strains present in a patient. Global assays, such as serology, are more suitable. The aim of this paper is to review the general phenomenon of diversity in H. pylori and to describe particular heterogeneities that are related to clinical outcome
  366. Blaser MJ. "Not all Helicobacter pylori strains are created equal: should all be eliminated?". Lancet. 1997 Apr 5;349(9057):1020-1022 (MEDL:9100641 #19132)       
  367. Blaser MJ. "The versatility of Helicobacter pylori in the adaptation to the human stomach". Journal of physiology & pharmacology. 1997 Sep;48(3):307-314 (MEDL:9376613 #19114)    

    A growing body of data indicates that H. pylori colonization of human is ancient, which is consistent with its high prevalence, chronicity of carriage, and generally low level of disease, which, when it occurs has only marginal or no effects on host reproductive capacity. All of these phenomena are markers for a relatively benign co-existence, which may include all of the entire spectrum of interactions from parasitism, through commensalism, to symbiosis. Recent studies suggest the emergence of 'quasispecies' during prolonged colonization, and the presence of multiple strains colonizing individual hosts. Such observations suggest that concepts of competition between strains and mutualism will be important in understanding the ecology of colonization and its effects on hosts. The presence of particular pathologies in the host may in part be a function of the characteristics of the bacterial population present. At a genomic level, H. pylori appears to adapt to changing conditions by point mutation, genomic rearrangement, and horizontal gene transfer, the latter is favored by its natural competence. The ability of H. pylori to alter phenotypic properties including superficial Lewis antigen expression and secretion of proinflammatory molecules is evidence of its sensitivity to environmental signals from the host. In such a universe, disease outcomes such as ulceration or neoplasia may be considered as accidents secondary to microbial persistence
  368. Blaser, M J. "Introduction: Medical Significance of H. pylori". Methods in molecular medicine. 1997;8:1-6 (MEDL:21351015 #416842)       

    Until the discovery of Helicobacter pylori in 1982, the normal human stomach was generally considered to be sterile, or transiently populated by oropharyngeal bacteria carried there by peristalsis. However, we now know that from one-third to one-half of the human population carries H. pylori, and that once infected, most persons remain infected for decades, if not for life (1).
  369. Blaser, M J. "Microbial causation of the chronic idiopathic inflammatory bowel diseases". Inflammatory bowel diseases. 1997 Fall;3(3):225-229 (MEDL:23282808 #416882)       

    SUMMARY: : The inability to find microbial causes for the idiopathic inflammatory bowel diseases has caused investigators and physicians to conclude that these IBDs are not infectious diseases. However, given the complexity of the intestinal flora and fauna and our very limited understanding of its microbiology, it is quite possible that one or more etiologic agents for the IBDs exist, but have not been detected. Consideration of a number of models for how persistent microbes could cause disease, as well as an analysis of the specific relationship of Helicobacter pylori to human disease, facilitates new paradigms for analysis of the IBDs. If the IBDs are due to microbial agents, then the numerous immunological abnormalities observed are thus secondary phenomena. The development of a more comprehensive knowledge base of the microbiology of the human intestine in general, and of IBD patients in particular, is most needed for advances to be made toward cure.
  370. Blaser, Martin J; Misiewicz, Jerzy Jacek. Helicobacter pylori and peptic ulcer disease. London : Rapid Science Publishers, 1997. 31 p. ; 28cm.
  371. Chen G; Sordillo EM; Ramey WG; Reidy J; Holt PR; Krajewski S; Reed JC; Blaser MJ; Moss SF. "Apoptosis in gastric epithelial cells is induced by Helicobacter pylori and accompanied by increased expression of BAK". Biochemical & biophysical research communications. 1997 Oct 20;239(2):626-632 (MEDL:9344882 #19113)       

    Carriage of the bacterium H. pylori in the human stomach is associated with evidence of increased epithelial cell apoptosis. This may be of significance in the etiology of gastritis, peptic ulcers, and neoplasia. The ability of H. pylori to directly induce epithelial apoptosis was examined in vitro by fluorescence and electron microscopy, flow cytometry, and DNA fragmentation ELISA. The induction of apoptosis by H. pylori was time and concentration-dependent and inhibited by preventing direct bacterial-epithelial cell contact. Apoptosis was accompanied by increased expression of Bak, with little change in expression of other Bcl-2 family proteins. The expression of Bak was also increased in gastric biopsies from patients colonized by H. pylori. Thus, H. pylori induces gastric epithelial cell apoptosis, by a Bak-dependent pathway
  372. Dunn BE; Cohen H; Blaser MJ. "Helicobacter pylori". Clinical microbiology reviews. 1997 Oct;10(4):720-741 (MEDL:9336670 #19115)    

    Helicobacter pylori is a gram-negative bacterium which causes chronic gastritis and plays important roles in peptic ulcer disease, gastric carcinoma, and gastric lymphoma. H. pylori has been found in the stomachs of humans in all parts of the world. In developing countries, 70 to 90% of the population carries H. pylori. In developed countries, the prevalence of infection is lower. There appears to be no substantial reservoir of H. pylori aside from the human stomach. Transmission can occur by iatrogenic, fecal-oral, and oral-oral routes. H. pylori is able to colonize and persist in a unique biological niche within the gastric lumen. All fresh isolates of H. pylori express significant urease activity, which appears essential to the survival and pathogenesis of the bacterium. A variety of tests to diagnose H. pylori infection are now available. Histological examination of gastric tissue, culture, rapid urease testing, DNA probes, and PCR analysis, when used to test gastric tissue, all require endoscopy. In contrast, breath tests, serology, gastric juice PCR, and urinary excretion of [15N]ammonia are noninvasive tests that do not require endoscopy. In this review, we highlight advances in the detection of the presence of the organism and methods of differentiating among types of H. pylori, and we provide a background for appropriate chemotherapy of the infection
  373. Dworkin J; Blaser MJ. "Molecular mechanisms of Campylobacter fetus surface layer protein expression". Molecular microbiology. 1997 Nov;26(3):433-440 (MEDL:9402015 #19107)       

    Cells of the Gram-negative bacteria Campylobacter fetus are covered by monomolecular arrays of surface layer proteins (SLPs) critical for both persistence in their natural hosts and for virulence. For C. fetus cells, expression of SLPs essentially eliminates C3b binding and their antigenic variation thwarts host immunological defences. Each cell possesses multiple partially homologous and highly conserved SLP gene cassettes, tightly clustered in the genome, that encode SLPs of 97-149 kDa. These attach non-covalently via a conserved N-terminus to the cell wall lipopolysaccharide. Recent studies indicate that C. fetus reassorts a single promoter, controlling SLP expression, and one, or more, complete open reading frame strictly by DNA inversion, and that rearrangement is independent of the distance between sites of inversion. In contrast to previously reported programmed DNA inversion systems, inversion in C. fetus is recA-dependent. These rearrangements permit variation in protein expression from the family of SLP genes and suggest an expanding paradigm of programmed DNA rearrangements among microorganisms
  374. Dworkin J; Blaser MJ. "Nested DNA inversion as a paradigm of programmed gene rearrangement". Proceedings of the National Academy of Sciences of the United States of America. 1997 Feb 4;94(3):985-990 (MEDL:9023369 #19136)       

    Programmed gene rearrangements are employed by a variety of microorganisms, including viruses, prokaryotes, and simple eukaryotes, to control gene expression. In most instances in which organisms mediate host evasion by large families of homologous gene cassettes, the mechanism of variation is not thought to involve DNA inversion. Here we report that Campylobacter fetus, a pathogenic Gram-negative bacterium, reassorts a single promoter, controlling surface-layer protein expression, and one or more complete ORFs strictly by DNA inversion. Rearrangements were independent of the distance between sites of inversion. These rearrangements permit variation in protein expression from the large surface-layer protein gene family and suggest an expanding paradigm of programmed DNA rearrangements among microorganisms
  375. Dworkin J; Shedd OL; Blaser MJ. "Nested DNA inversion of Campylobacter fetus S-layer genes is recA dependent". Journal of bacteriology. 1997 Dec;179(23):7523-7529 (MEDL:9393719 #19111)    

    Wild-type strains of Campylobacter fetus are covered by a monomolecular array of surface layer proteins (SLPs) critical for virulence. Each cell possesses eight SLP gene cassettes, tightly clustered in the genome, that encode SLPs of 97 to 149 kDa. Variation of SLP expression occurs by a mechanism of nested DNA rearrangement that involves the inversion of a 6.2-kb sapA promoter-containing element alone or together with one or more flanking SLP gene cassettes. The presence of extensive regions of identity flanking the 5' and 3' ends of each SLP gene cassette and of a Chi-like recognition sequence within the 5' region of identity suggests that rearrangement of SLP gene cassettes may occur by a generalized (RecA-dependent) homologous recombination pathway. To explore this possibility, we cloned C. fetus recA and created mutant strains by marker rescue, in which recA is disrupted in either S+ or S- strains. These mutants then were assessed for their abilities to alter SLP expression either in the presence or absence of a complementary shuttle plasmid harboring native recA. In contrast to all previously reported programmed DNA inversion systems, inversion in C. fetus is recA dependent
  376. Eaton KA; Cover TL; Tummuru MK; Blaser MJ; Krakowka S. "Role of vacuolating cytotoxin in gastritis due to Helicobacter pylori in gnotobiotic piglets". Infection & immunity. 1997 Aug;65(8):3462-3464 (MEDL:9234813 #19123)    

    To investigate the role of the Helicobacter pylori cytotoxin in the pathogenesis of gastritis, gnotobiotic piglets were colonized with either toxigenic H. pylori or a nontoxigenic isogenic mutant. Only piglets given the toxigenic strain developed toxin-neutralizing antibodies (indicating that toxin is expressed in vivo), but there was no difference in bacterial colonization, epithelial vacuolation, or gastritis between the two groups of piglets
  377. Fujimoto S; Allos BM; Misawa N; Patton CM; Blaser MJ. "Restriction fragment length polymorphism analysis and random amplified polymorphic DNA analysis of Campylobacter jejuni strains isolated from patients with Guillain-Barre syndrome". Journal of infectious diseases. 1997 Oct;176(4):1105-1108 (MEDL:9333178 #19116)       

    Campylobacter jejuni serotype O19 strains associated with the Guillain-Barre syndrome (GBS) and other strains were examined by restriction fragment length polymorphism (RFLP) analysis of polymerase chain reaction products of the flaA genes and by random amplified polymorphic DNA (RAPD) analysis. RFLP analysis showed that regardless of LIO serotype, geographic origins, or association with GBS, the O19 isolates shared an identical digestion pattern by each of four restriction endonucleases, DdeI, MboI, MseI, and AluI. In contrast, among C. jejuni O1 or O2 strains, RFLP patterns were different even among strains of the same LIO serotype. The results of the RAPD analysis were consistent with the flaA RFLP data. These data indicate that all of the O19 strains that were tested were closely related to one another whether they were or were not associated with GBS
  378. Grandis JR; Perez-Perez GI; Yu VL; Johnson JT; Blaser MJ. "Lack of serologic evidence for Helicobacter pylori infection in head and neck cancer". Head & neck. 1997 May;19(3):216-218 (MEDL:9142522 #19131)       

    BACKGROUND: Several epidemiologic investigations have established a link between Helicobacter pylori infection and gastric malignancies. Because the stomach is in continuity with the oral cavity and the bacterium has been isolated from dental plaque and saliva, we hypothesized that H. pylori infection of the upper aerodigestive tract might result in mucosal disruption, allowing for subsequent transformation by known carcinogens such as tobacco and alcohol. METHODS: To test this hypothesis, we assayed for the presence of IgG antibodies to H. pylori in the serum of 21 patients with squamous cell carcinoma of the head and neck (SCCHN) and 21 matched controls without a history of head and neck cancer. RESULTS: The incidence of seropositivity in the SCCHN patients was 57% and in the controls, 62% (p > 0.05). CONCLUSIONS: These data do not support an etiologic role for H. pylori infection in head and neck cancer
  379. Groves FD; Zhang L; Li JY; You WC; Chang YS; Zhao L; Liu WD; Rabkin CS; Perez-Perez GI; Blaser MJ; Gail MH. "Comparison of two enzyme-linked immunosorbent assay tests for diagnosis of Helicobacter pylori infection in China". Cancer epidemiology biomarkers & prevention. 1997 Jul;6(7):551-552 (MEDL:9232345 #19126)    

    An ELISA based on a pool of United States strains of Helicobacter pylori was compared with a newly developed ELISA based on a pool of Chinese strains. Both assays were tested using sera from 132 Chinese study subjects with biopsy-proven H. pylori infection. Using cutpoints designed to yield equal specificities of 94.9% in an uninfected control population, the sensitivity of the Chinese assay was 100.0%, compared to 97.7% for the United States assay (P = 0.25 by McNemar test). These results suggest that a H. pylori assay based on pooled antigens from United States strains will perform as well in the rural Chinese population as one based on antigens from Chinese strains
  380. Hook-Nikanne J; Perez-Perez GI; Blaser MJ. "Antigenic characterization of Helicobacter pylori strains from different parts of the world". Clinical & diagnostic laboratory immunology. 1997 Sep;4(5):592-597 (MEDL:9302211 #19120)    

    Although Helicobacter pylori is considered to be relatively homogeneous at the phenotypic level, our aim was to describe its antigenic heterogeneity and to examine differences in host response. Whole-cell lysates of H. pylori strains originally isolated from persons from Africa, the People's Republic of China, Japan, Peru, Thailand, or the United States or from monkeys were analyzed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Immunoblots were performed by using sera from H. pylori-infected persons from different areas of the world and rabbit immune sera against H. pylori antigens. Specific H. pylori antibody responses in persons from the United States and the People's Republic of China were analyzed by enzyme-linked immunosorbent assay with antigens prepared from U.S. or Chinese strains. Despite diverse origins, the strains showed conserved major bands of 84, 60, 56, 31, and 25 kDa. Although there were clear differences in minor bands, there was no obvious geographic pattern. The anti-CagA serum recognized 120- to 140-kDa bands in cagA+ strains from around the world. Although antigenic preparations from individual U.S. or Chinese strains were not optimally sensitive for serologic detection of infection in the heterologous country, use of pools of strains largely overcame this phenomenon. We conclude that conserved H. pylori antigens exist and are recognized by sera from persons from many parts of the world. The heterogeneity of H. pylori antigens and the serological responses of infected hosts is not fully explained by geographic differences. Use of pools may allow development of antigens for serologic testing in any country
  381. Karita M; Etterbeek ML; Forsyth MH; Tummuru MK; Blaser MJ. "Characterization of Helicobacter pylori dapE and construction of a conditionally lethal dapE mutant". Infection & immunity. 1997 Oct;65(10):4158-4164 (MEDL:9317022 #19119)    

    Helicobacter pylori colonizes the human gastric mucosa and causes gastritis, ulceration, or gastric cancer. A previously uncharacterized region of the H. pylori genome was identified and sequenced. This region includes a putative operon containing three open reading frames termed gidA (1,866 bp), dapE (1,167 bp), and orf2 (753 bp); the gidA and dapE products are highly homologous to other bacterial proteins. In E. coli, dapE encodes N-succinyl-L-diaminopimelic acid desuccinylase, which catalyzes the hydrolysis of N-succinyl-L-diaminopimelic acid to L-diaminopimelic acid (L-DAP) and succinate. When wild-type H. pylori strains were transformed to select for dapE mutagenesis, mutants were present when plates were supplemented with DAP but not with lysine; orf2 mutants were selected without DAP supplementation. Consistent with the finding that GidA is essential in Escherichia coli, we were unable to obtain a gidA mutant in H. pylori despite evidence that insertional mutagenesis had occurred. The positions of gidA, dapE, and orf2 suggest that they form an operon, which was supported by slot blot RNA hybridization and reverse transcriptase PCR studies. The data imply that the H. pylori dapE mutant may be useful as a conditionally lethal vaccine
  382. Kidd M; Miu K; Tang LH; Perez-Perez GI; Blaser MJ; Sandor A; Modlin IM. "Helicobacter pylori lipopolysaccharide stimulates histamine release and DNA synthesis in rat enterochromaffin-like cells". Gastroenterology. 1997 Oct;113(4):1110-1117 (MEDL:9322505 #19118)       

    BACKGROUND & AIMS: Helicobacter pylori alterations in gastric acid output and mucosal proliferation may involve the enterochromaffin-like (ECL) cell. To test whether H. pylori affects ECL cell histamine secretion and proliferation, the effect of lipopolysaccharide (LPS) on ECL cell function in vitro was investigated. METHODS: Using a rat ECL cell preparation of high purity (+/-95%), basal and stimulated histamine secretion and DNA synthesis were measured by enzyme immunoassay and bromodeoxyuridine (BrdU) uptake, respectively. RESULTS: Escherichia coli LPS (10(-12) to 10(-6) mol/L) had no effect on basal and stimulated histamine secretion at concentrations of > 10(-6) mol/L. H. pylori LPS stimulated basal and gastrin-stimulated histamine secretion. These effects were completely inhibited by somatostatin (10(-10) mol/L) but not by the gastrin receptor antagonist L365,260 at 10(-6) mol/L. E. coli LPS had a weak stimulatory effect on ECL cell BrdU uptake at 10(-6) mol/L but had no effect on gastrin-stimulated BrdU uptake. H. pylori LPS did not stimulate basal synthesis but significantly increased (1.5-fold) gastrin-stimulated BrdU uptake. CONCLUSIONS: H. pylori influences both ECL cell proliferation and secretion in vitro. An interaction between H. pylori LPS and ECL cells may contribute to the reported abnormalities in acid secretion and gastric pathobiology noted in H. pylori infections
  383. Kirkland T; Viriyakosol S; Perez-Perez GI; Blaser MJ. "Helicobacter pylori lipopolysaccharide can activate 70Z/3 cells via CD14". Infection & immunity. 1997 Feb;65(2):604-608 (MEDL:9009319 #19137)    

    Helicobacter pylori persistently colonizes the human gastrointestinal tract and is associated with chronic gastritis and, in some cases, peptic ulcer disease or gastric neoplasms. One factor in the persistence of this organism may be its inability to elicit a strong inflammatory response. Lipopolysaccharide (LPS) is a proinflammatory substance found in the cell walls of all gram-negative bacteria. H. pylori LPS has been found by several different measures to be less active than LPS from Enterobacteriaceae. This study addresses the role of CD14 and LPS-binding protein in the cellular response to H. pylori LPS. We report that H. pylori LPS activates mammalian cells expressing CD14 at much lower LPS concentrations than those for control cells not expressing CD14. The maximal activation of CD14-70Z/3 cells by H. pylori LPS also requires LPS-binding protein. H. pylori LPS at concentrations as high as 30 microg/ml does not elicit an interleukin-8 (IL-8) response from the epithelial cell line SW620 in the presence of CD14; 10 ng of Escherichia coli LPS per ml elicits a maximal IL-8 response. Furthermore, in contrast to some other types of LPS with little activity, H. pylori LPS does not inhibit the CD14-70Z/3 cell response to E. coli LPS. From these studies, we conclude that H. pylori LPS, though much less active than E. coli LPS, stimulates cells via CD14
  384. Lang DR; Allos BM; Blaser MJ. "Workshop summary and recommendations regarding the development of Guillain-Barre syndrome following Campylobacter infection". Journal of infectious diseases. 1997 Dec;176 Suppl 2(1):S198-S200 (MEDL:9396711 #19109)       
  385. Lang, Dennis R; Blaser, Martin J. Development of Guillain-Barre syndrome following Campylobacter infection . Chicago : University of Chicago Press, 1997. p. 91-200 ; 28cm.
  386. McGowan CC; Cover TL; Blaser MJ. "Analysis of F1F0-ATPase from Helicobacter pylori". Infection & immunity. 1997 Jul;65(7):2640-2647 (MEDL:9199431 #19127)    

    The adaptive mechanisms that permit Helicobacter species to survive within the gastric mucosa are not well understood. The proton-translocating F1F0-ATPase is an important enzyme for regulating intracellular pH or synthesizing ATP in many other enteric bacteria; therefore, we used degenerate primers derived from conserved bacterial F1F0-ATPase sequences to PCR amplify and clone the gene (atpD) encoding the H. pylori F1F0-ATPase beta subunit. The deduced amino acid sequences of the F1F0-ATPase beta subunits from H. pylori and Wolinella succinogenes were 85% identical (91% similar). To characterize a potential functional role of F1F0-ATPase in H. pylori, H. pylori or Escherichia coli cells were incubated for 60 min in buffered solutions at pH 7, 6, 5, or 4, with or without 100 microM N,N'-dicyclohexylcarbodiimide (DCCD), a specific inhibitor of F1F0-ATPase. At pH 5 and 4, there was no significant decrease in survival of H. pylori in the presence of DCCD compared to its absence, whereas incubation with DCCD at pH 7 and 6 significantly decreased H. pylori survival. E. coli survival was unaffected by DCCD at any pH value tested. We next disrupted the cloned beta-subunit sequence in E. coli by insertion of a kanamycin resistance cassette and sought to construct an isogenic F1F0-ATPase H. pylori mutant by natural transformation and allelic exchange. In multiple transformations of H. pylori cells grown at pH 6 or 7, no kanamycin-resistant F1F0 mutants were isolated, despite consistently successful mutagenesis of other H. pylori genes by using a similar approach and PCR experiments providing evidence for integration of the kanamycin resistance cassette into atpD. The sensitivity of H. pylori to DCCD at pH 7 and 6, and failure to recover F1F0 H. pylori mutants under similar conditions, suggests that the function of this enzyme is required for survival of H. pylori at these pHs
  387. Peek RM; Blaser MJ. "Pathophysiology of Helicobacter pylori-induced gastritis and peptic ulcer disease". American journal of medicine. 1997 Feb;102(2):200-207 (MEDL:9217571 #19135)       

    Helicobacter pylori causes persistent infection and inflammation in the human stomach, yet only a small fraction of persons harboring this organism develop peptic ulcer disease. An important question is why this variation in infection outcome exists. Recent studies have demonstrated that H pylori isolates possess substantial phenotypic and genotypic diversity that may engender differential host inflammatory responses that influence clinical outcome. Further investigation in this field may help to define which H pylori-infected persons bear the highest risk for subsequent development of peptic ulcer disease, and thus enable physicians to focus eradication therapy
  388. Peek RM; Moss SF; Tham KT; Perez-Perez GI; Wang S; Miller GG; Atherton JC; Holt PR; Blaser MJ. "Helicobacter pylori cagA+ strains and dissociation of gastric epithelial cell proliferation from apoptosis". Journal of the National Cancer Institute. 1997 Jun 18;89(12):863-868 (MEDL:9196252 #19128)       

    BACKGROUND: Infection with Helicobacter pylori induces chronic gastritis in virtually all infected persons, and such gastritis has been associated with an increased risk of developing gastric cancer. This risk is further enhanced with cagA+ (positive for cytotoxin-associated gene A) H. pylori strains and may be a consequence of induced gastric cell proliferation and/or alteration in apoptosis (programmed cell death) in the gastric epithelium. PURPOSE: To determine whether the H. pylori cagA genotype and another virulence-related characteristic, the vacA (vacuolating cytotoxin A) s1a genotype, differentially affect epithelial cell proliferation, apoptosis, and the histologic parameters of inflammation and injury, we quantitated these characteristics in infected and uninfected persons. METHODS: Fifty patients underwent upper gastrointestinal endoscopy, and biopsy specimens were taken. Apoptotic cells in the specimens were quantitated after terminal deoxynucleotidyl transferase labeling of DNA fragments with digoxigenin-deoxyuridine triphosphate; epithelial cell proliferation was scored by immunohistochemical analysis of the proliferation-associated antigen Ki-67. Antibodies directed against H. pylori and CagA protein were measured in the serum of patients by means of enzyme-linked immunosorbent assays. Analysis of H. pylori genomic DNA, by use of the polymerase chain reaction, was performed to determine the cagA and vacA genotypes. Acute and chronic inflammation, epithelial cell degeneration, mucin depletion, intestinal metaplasia, glandular atrophy, and vacuolation were each scored in a blinded manner. Reported P values are two-sided. RESULTS: Persons harboring cagA+ strains (n = 20) had significantly higher gastric epithelial proliferation scores than persons infected with cagA-strains (n = 9) or uninfected persons (n = 21) (P = .025 and P<.001, respectively), but the difference in cell proliferation between the latter two groups was not statistically significant. The number of apoptotic cells per 100 epithelial cells (apoptotic index) in persons infected with cagA+ strains was lower than in persons infected with cagA-strains (P = .05). Apoptotic indices in the cagA+ group were similar to those in the uninfected group (P = .2). Epithelial cell proliferation was significantly correlated with acute gastric inflammation, but only in the cagA+ group (r = .44; P = .006). The cagA+ and vacA s1a genotypes were found to be concordant, confirming the close relationship between these virulence-related genotypes. CONCLUSIONS: Gastric mucosal proliferation was significantly correlated with the severity of acute gastritis in persons infected with cagA+ vacA s1a strains of H. pylori. This increased proliferation was not accompanied by a parallel increase in apoptosis. IMPLICATIONS: Increased cell proliferation in the absence of a corresponding increase in apoptosis may explain the heightened risk for gastric carcinoma that is associated with infection by cagA+ vacA s1a strains of H. pylori
  389. Perez-Perez GI; Bhat N; Gaensbauer J; Fraser A; Taylor DN; Kuipers EJ; Zhang L; You WC; Blaser MJ. "Country-specific constancy by age in cagA+ proportion of Helicobacter pylori infections". International journal of cancer. 1997 Jul 29;72(3):453-456 (MEDL:9247289 #19124)       

    Helicobacter pylori strains may be either cagA+ or cagA-, and in logitudinal studies, infection with a cagA+ strain has been associated with increased risk for the development of atrophic gastritis and cancer of the distal stomach. We sought to determine the relative proportion of strains producing CagA in different geographic locales, and the extent to which CagA seroprevalence varied in countries with different gastric and esophageal cancer rates. Using an enzyme-linked immunosorbent assay (ELISA) to detect serum IgG to CagA, we examined sera from 468 asymptomatic H. pylori-infected adults from Canada, Peru, China, Thailand, The Netherlands and 3 different ethnic groups in New Zealand. The CagA seroprevalence in Peru and Thailand (82.2% and 78.8%, respectively) were each substantially higher than for the Chinese (37.9%), Canadian (41.9%), Dutch (39.0%) and New Zealand (28.2%) subjects, but within each population, rates were relatively constant across gender and age groups. Reported gastric but not esophageal cancer rates for the 8 studied populations were significantly associated with H. pylori seroprevalence. Variation in CagA positivity rates was not significantly associated with variation in either gastric or esophageal cancer rates. Our data suggest that CagA seroprevalence is not the major factor influencing gastric cancer rates
  390. Perez-Perez GI; Cutler AF; Blaser MJ. "Value of serology as a noninvasive method for evaluating the efficacy of treatment of Helicobacter pylori infection". Clinical infectious diseases. 1997 Nov;25(5):1038-1043 (MEDL:9402353 #19106)       

    The systemic humoral response to Helicobacter pylori was studied in 86 infected adult patients before antimicrobial therapy and at intervals following therapy. Endoscopy with collection of biopsy specimens was performed immediately before treatment; a 13C-labeled urea breath test was performed, and blood specimens were collected before treatment and at 1, 3, 6, 9, and 12 months after treatment. Serum samples from three patient groups (eradication success [n = 50], eradication failure [n = 16], and no treatment [n = 20]) were assayed for IgA and IgG antibodies to H. pylori by enzyme-linked immunosorbent assay. Levels of antibody to H. pylori before treatment were similar in all three groups. As expected, the no treatment and eradication failure groups had no significant changes in antibody levels during the study period. In contrast, for the eradication success group, the specific IgA and IgG antibody levels decreased progressively and significantly. We conclude that serology is a potentially useful way to monitor the success of treatment of H. pylori infection without using invasive or more expensive methods
  391. Schuster M; Blaser MJ; Nachamkin I. "Serendipitous detection of persistent Campylobacter jejuni subspecies jejuni bacteremia in a patient undergoing bone marrow transplantation". Clinical infectious diseases. 1997 Jun;24(6):1270-1270 (MEDL:9195103 #19130)       
  392. Sharma SA; Miller GG; Peek RA; Perez-Perez G; Blaser MJ. "T-cell, antibody, and cytokine responses to homologs of the 60-kilodalton heat shock protein in Helicobacter pylori infection". Clinical & diagnostic laboratory immunology. 1997 Jul;4(4):440-446 (MEDL:9220161 #19125)    

    For Helicobacter pylori, the hsp60 heat shock protein encoded by hspB is being considered as a potential candidate for subunit vaccines. We investigated the humoral and cellular responses to H. pylori hsp60 and its cross-reactivity with the homologous Mycobacterium bovis p65 protein and autologous human hsp60 protein. H. pylori-infected persons had significantly higher levels than uninfected persons of serum immunoglobulin G antibodies recognizing H. pylori hsp60, but not M. bovis p65 or human hsp60, as determined by enzyme-linked immunosorbent assay. In contrast, immunoblotting demonstrated cross-reactivity of H. pylori hsp60 with human hsp60. T-cell recognition of H. pylori hsp60 was found in both infected and uninfected subjects, and there was no recognition of human hsp60. T cells from infected and uninfected subjects that had been activated in response to H. pylori hsp60 or M. bovis p65 were phenotypically similar but appeared to secrete different levels of gamma interferon and interleukin-10. These results demonstrate an apparent difference in the epitopes recognized by the T and B cells responding to H. pylori hsp60 in H. pylori-infected persons. In contrast to the T-cell responses, which were highly variable in all subjects and showed no recognition of autologous proteins, a specific B-cell response that may have cross-reactivity to human hsp60 is evident in some infected subjects
  393. Wirth HP; Yang M; Peek RM; Tham KT; Blaser MJ. "Helicobacter pylori Lewis expression is related to the host Lewis phenotype". Gastroenterology. 1997 Oct;113(4):1091-1098 (MEDL:9322503 #19117)       

    BACKGROUND & AIMS: Lewis antigens occur in human gastric epithelium and in Helicobacter pylori lipopolysaccharide; their expression is polymorphic in both. Autoimmune mechanisms induced by bacterial Lewis expression have been proposed to cause gastritis. The aim of this study was to examine the relationship between bacterial and host gastric Lewis expression, as determined by the erythrocyte Lewis(a/b) phenotype, and between gastric histopathology and bacterial Lewis expression. METHODS: H. pylori Lewis expression was determined by enzyme immunoassays, erythrocyte Lewis phenotype was assessed by agglutination tests, and gastric histopathology was scored blindly. RESULTS: The host Lewis phenotype was (a+b-) in 15, (a-b+) in 34, and (a-b-) in 17 patients, therefore expressing Lewis x, y, or neither as their major gastric epithelial Lewis type 2 antigen. H. pylori from patients with Lewis(a+b-) expressed Lewis x more than y (1147 +/- 143 vs. 467 +/- 128 optical density units [ODU]; P = 0.006), isolates from patients with Lewis(a-b+) expressed Lewis x less than y (359 +/- 81 vs. 838 +/- 96 ODU; P = 0.0001), and isolates from Lewis(a-b-) patients expressed Lewis x and y approximately equally. Gastritis was unrelated to H. pylori Lewis expression. CONCLUSIONS: In mimicking host gastric epithelium, H. pylori cells not only express Lewis x and y, but the relative proportion of expression corresponds to the host Lewis phenotype, suggesting selection for host-adapted organisms
  394. Xu Q; Peek RM; Miller GG; Blaser MJ. "The Helicobacter pylori genome is modified at CATG by the product of hpyIM". Journal of bacteriology. 1997 Nov;179(21):6807-6815 (MEDL:9352933 #19112)    

    To understand mechanisms of DNA methylation in Helicobacter pylori, a human pathogen associated with peptic ulcer disease and gastric adenocarcinoma, we cloned a putative DNA methyltransferase gene, hpyIM. This gene contains a 990-bp open reading frame encoding a 329-amino-acid protein, M.HpyI. Sequence analysis revealed that M.HpyI was closely related to CATG-recognizing adenine DNA methyltransferases, including M.NlaIII in N. lactamica. hpyIM was present in all H. pylori strains tested. DNA from wild-type H. pylori strains was resistant to digestion by SphI and NlaIII, which recognize DNA at sites containing CATG, whereas their isogenic hpyIM mutants were susceptible, indicating lack of modification. Overexpression of hpyIM in Escherichia coli rendered DNA from these cells resistant to NlaIII digestion, confirming the role of hpyIM in modifying CATG sites. We conclude that hpyIM encodes a DNA methyltransferase, M.HpyI, that is well conserved among diverse H. pylori strains and that modifies H. pylori genomes at CATG sites
  395. Atherton JC; Tham KT; Peek RM; Cover TL; Blaser MJ. "Density of Helicobacter pylori infection in vivo as assessed by quantitative culture and histology". Journal of infectious diseases. 1996 Sep;174(3):552-556 (MEDL:8769613 #19145)       

    Helicobacter pylori density was assessed by quantitative culture and histologic examination of gastric biopsy specimens from 29 H. pylori-infected dyspeptic patients. Density was correlated with cagA and vacA genotypes (assessed by polymerase chain reaction and colony hybridization), gastric inflammation and epithelial injury (assessed histologically), and peptic ulceration. Quantitative culture was more reproducible than histology, and antral density was more reproducible than corpus density. Mean antral density of cagA+/vacA sl strains was 4-fold higher than that of cagA-/vacA s2 strains (1.9 X 10(6) vs. 4.5 x 10(5) cfu/g, P = .02). Antral density was associated with mucosal neutrophilic and lymphocytic infiltration (P < .01) and with epithelial injury (P < .05). Mean antral bacteria] density was 5-fold higher in duodenal ulcer patients than in others (P = .005). In conclusion, H. pylori density in vivo is easily quantified and is associated with bacterial virulence determinants, gastric inflammation, and duodenal ulceration, suggesting a central role in pathogenesis
  396. Blaser MJ. "How safe is our food? Lessons from an outbreak of salmonellosis [Comment]". New England journal of medicine. 1996 May 16;334(20):1324-1325 (MEDL:8609952 #19150)       
  397. Blaser MJ. "Role of vacA and the cagA locus of Helicobacter pylori in human disease". Alimentary pharmacology & therapeutics. 1996 Apr;10 Suppl 1(20):73-77 (MEDL:8730262 #19151)    

    Helicobacter pylori are 'slow' bacteria that may cause disease decades after acquisition. Bacterial pathogenesis often involves features, including conserved genes, shared by many different species. As such, despite its unique niche in the human body, the pathogenesis of H. pylori infection most likely shares mechanisms with other bacteria. In this paper, two genes, vacA and cagA, which appear unique to H. pylori and which may reflect the particular requirements of H. pylori for long-term residence in the human stomach will be discussed. At present the function of these genes for H. pylori is not known yet other characteristics have been defined
  398. Blaser MJ. "The bacteria behind ulcers". Scientific american. 1996 Feb;274(2):104-107 (MEDL:8560206 #19154)       
  399. Blaser MJ; Crabtree JE. "CagA and the outcome of Helicobacter pylori infection [Comment]". American journal of clinical pathology. 1996 Nov;106(5):565-567 (MEDL:8929462 #19140)    
  400. Cover TL; Blaser MJ. "Helicobacter pylori infection, a paradigm for chronic mucosal inflammation: pathogenesis and implications for eradication and prevention". Advances in internal medicine. 1996;41(2):85-117 (MEDL:8903587 #19155)    
  401. Dubois A; Berg DE; Incecik ET; Fiala N; Heman-Ackah LM; Perez-Perez GI; Blaser MJ. "Transient and persistent experimental infection of nonhuman primates with Helicobacter pylori: implications for human disease". Infection & immunity. 1996 Aug;64(8):2885-2891 (MEDL:8757808 #19147)    

    Helicobacter pylori can establish chronic infection in the human gastric mucosa, and it is a major cause of peptic ulcer disease and a principal risk factor for gastric cancer. This creates a need for H. pylori infection models that mimic the human condition. To test the suitability of rhesus monkeys as infection models, H. pylori-free animals were inoculated intragastrically with mixtures of H. pylori strains, bacteria recovered from colonized animals were typed by arbitrarily primed PCR, and host inflammatory and immunologic responses were monitored. Among five H. pylori-free animals inoculated with a mixture of two human strains plus one monkey strain, one became persistently infected and one became only transiently infected. The recovered bacteria matched the monkey input strain in DNA fingerprint. A subsequent trial using two new human isolates and three animals that had resisted colonization by the monkey strain resulted in persistent infection in one animal and transient infection in two others. Antral gastritis, anti-H. pylori serum immunoglobulin G, and atrophy all increased, but with patterns that differed among animals. We conclude that (i) rhesus monkeys can be infected experimentally with H. pylori, (ii) individuals differ in susceptibility to particular bacterial strains, (iii) infections may be transient, and (iv) the fitness of a particular strain for a given host helps determine the consequences of exposure to that strain
  402. Dworkin J; Blaser MJ. "Generation of Campylobacter fetus S-layer protein diversity utilizes a single promoter on an invertible DNA segment". Molecular microbiology. 1996 Mar;19(6):1241-1253 (MEDL:8730866 #19152)       

    Wild-type strains of Campylobacter fetus contain a monomolecular array of surface layer proteins (SLPs) and vary the antigenicity of the predominant SLP expressed. Reciprocal recombination events among the eight genomic SLP gene cassettes, which encode 97- to 149 kDa SLPs, permit this variation. To explore whether SLP expression utilizes a single promoter, we created mutant bacterial strains using insertional mutagenesis by rescue of a marker from plasmids. Experimental analysis of the mutants created clearly indicates that SLP expression solely utilizes the single sapA promoter, and that for variation C. fetus uses a mechanism of DNA rearrangement involving inversion of a 6.2 kb segment of DNA containing this promoter. This DNA inversion positions the sapA promoter immediately upstream of one of two oppositely oriented SLP gene cassettes, leading to its expression. Additionally, a second mechanism of DNA rearrangement occurs to replace at least one of the two SLP gene cassettes bracketing the invertible element. As previously reported promoter inversions in prokaryotes, yeasts and viruses involve alternate expression of at most two structural genes, the ability of C. fetus to use this phenomenon to express one of multiple cassettes is novel
  403. Ellison RT; Perez-Perez G; Welsh CH; Blaser MJ; Riester KA; Cross AS; Donta ST; Peduzzi P. "Risk factors for upper gastrointestinal bleeding in intensive care unit patients: role of helicobacter pylori. Federal Hyperimmune Immunoglobulin Therapy Study Group". Critical care medicine. 1996 Dec;24(12):1974-1981 (MEDL:8968264 #19139)       

    OBJECTIVE: To determine the role of preexisting Helicobacter pylori infection in the development of acute upper gastrointestinal (GI) hemorrhage in intensive care unit (ICU) patients in relation to other potential predisposing risk factors. DESIGN: Prospective, multicenter, cohort study. SETTING: Medical and surgical ICUs in six tertiary care Department of Veterans Affairs Medical Centers. PATIENTS: Eight-hundred seventy-four patients without previous GI bleeding or peptic ulcer disease who were enrolled in a multicenter, randomized, controlled trial of prophylactic intravenous immunoglobulin to prevent ICU-associated infections. INTERVENTIONS: This substudy of the larger intravenous immunoglobulin study only involved data analysis and had no intervention. All patients were enrolled in the larger study where they received intravenous immunoglobulin or placebo as intervention. MEASUREMENTS AND MAIN RESULTS: Patients were prospectively evaluated for the development of acute upper GI hemorrhage while in an ICU. Anti-H. pylori immunoglobulin G and immnoglobulin A concentrations were determined by enzyme immunoassay on preintervention serum samples. Seventy-six (9%) patients had over upper GI bleeding and a mortality rate of 49%, as compared with a 15% mortality rate in patients who did not bleed (p < .001). By logistic regression analysis, the following factors were associated with an increased risk of bleeding: acute hepatic failure, prolonged duration of nasogastric tube placement, alcoholism, and an increased serum concentration of anti-H. pylori immunoglobulin A. CONCLUSIONS: Increased anti-H. pylori immunoglobulin A concentrations, prolonged nasogastric intubation, alcoholism, and acute hepatic failure were found to be independently correlated with the development of acute GI bleeding in an ICU setting. These observations should be prospectively confirmed in an independent population before being used for treatment guidelines
  404. Gonzalez-Valencia G; Perez-Perez GI; Washburn RG; Blaser MJ. "Susceptibility of Helicobacter pylori to the bactericidal activity of human serum". Helicobacter. 1996 Mar;1(1):28-33 (MEDL:9398910 #19108)    

    BACKGROUND: Human serum represents an important barrier to the entry of most mucosal organisms into tissues and to the systemic circulation. If at all present, Helicobacter pylori within gastric tissue is rare, and bacteremia for this organism has been described only once. METHODS: To assess the susceptibility of H. pylori to the bactericidal activity present in normal human serum (NHS), we examined 13 H. pylori isolates. To assess the contributions of the classical and alternative complement pathways to killing, we added either C2-deficient or factor B-deficient serum, respectively, to heat-inactivated NHS. Also we assessed the ability of the strains to bind 125I-C3. RESULTS: After incubation for 60 minutes at 37 degrees C, all 13 H. pylori strains were killed by NHS; heating to 56 degrees C for 30 minutes ablated killing, indicating complement dependence for this phenomenon. In the absence of an antibody source, there was no killing when either an alternative or classical complement pathway source was used. Adding B-deficient serum to heat-inactivated normal human serum did not restore killing, but adding C2-deficient serum permitted partial killing. All of the 13 strains bound 125I-C3. Although the kinetics varied from strain to strain, C3 bound was significantly correlated (r = 0.61, p = 0.03) with serum susceptibility. CONCLUSIONS: H. pylori are susceptible to complement, alternative pathway activation appears critical, and C3 binding is a major locus of variability
  405. Harris PR; Cover TL; Crowe DR; Orenstein JM; Graham MF; Blaser MJ; Smith PD. "Helicobacter pylori cytotoxin induces vacuolation of primary human mucosal epithelial cells". Infection & immunity. 1996 Nov;64(11):4867-4871 (MEDL:8890255 #19142)    

    We investigated whether Helicobacter pylori cytotoxin induces vacuolation in primary epithelial cells from normal human mucosa. Epithelial cells purified by enzyme digestion and elutriation were evaluated for vacuolation in a blinded protocol by light and electron microscopy before and after incubation with culture supernatant (CS) from H. pylori 60190, which has vacuolating activity for HeLa cells (Tox+), and isogenic H. pylori mutant 60190-v1, which lacks this activity (Tox-). Primary epithelial cells (>98% pure) exposed to CS from Tox+ H. pylori exhibited marked vacuolation (52% +/- 5% of cells) compared with epithelial cells exposed to either CS from Tox- H. pylori (23% +/- 3.2%) or uninoculated control broth (23% +/- 3.7%) (P < 0.05) by light microscopy, which was confirmed by electron microscopy and antibody inhibition studies. These are the first data to show that H. pylori cytotoxin causes vacuolation of primary human mucosal epithelial cells
  406. Harris PR; Mobley HL; Perez-Perez GI; Blaser MJ; Smith PD. "Helicobacter pylori urease is a potent stimulus of mononuclear phagocyte activation and inflammatory cytokine production". Gastroenterology. 1996 Aug;111(2):419-425 (MEDL:8690207 #19148)       

    BACKGROUND & AIMS: Helicobacter pylori surface proteins induce the production of proinflammatory mediators by mononuclear phagocytes, but the protein responsible for this stimulation has not been identified. This study determined whether urease, the major component of the soluble proteins extracted from H. pylori grown in culture, activates mononuclear phagocytes and stimulates them to produce proinflammatory cytokines. METHODS: Primary human blood monocytes were incubated with column-purified H. pylori urease and assayed by flow cytometry, Immunoassay, and reverse-transcription polymerase chain reaction for phenotypic, functional, and molecular evidence of activation. RESULTS: H. pylori urease induced monocyte expression of surface interleukin 2 receptors and increased expression of HLA-DR, phenotypic changes consistent with activation. Urease also stimulated dose-dependent production of interleukin 1 beta, interleukin 6, interleukin 8, and tumor necrosis factor alpha peptides and messenger RNA. These urease-induced phenotypic and functional changes were inhibited by preincubation of the urease with antisera to H. pylori whole bacteria, purified urease, or the 31-kilodalton subunit of urease. CONCLUSIONS: Among the soluble proteins released by H. pylori, urease is capable of activating monocytes for proinflammatory cytokines production. The local production of cytokines by urease-stimulated mononuclear phagocytes may play a central role in the development of H. pylori gastroduodenal inflammation
  407. Karita M; Tummuru MK; Wirth HP; Blaser MJ. "Effect of growth phase and acid shock on Helicobacter pylori cagA expression". Infection & immunity. 1996 Nov;64(11):4501-4507 (MEDL:8890198 #19144)    

    Helicobacter pylori strains possessing cagA are associated with peptic ulceration. To understand the regulation of expression of cagA, picB, associated with interleukin-8 induction, and ureA, encoding the small urease subunit, we created gene fusions of cagA, ureA, and picB of strain 3401, using a promoterless reporter (xylE). Expression of XylE after growth in broth culture revealed that basal levels of expression of cagA and urea in H. pylori were substantially greater than for picB. For cagA expression in stationary-phase cells, brief exposure to acid pH caused a significant increase in xylE expression compared with neutral pH. In contrast, expression of xylE in urea or picB decreased after parallel exposure to acid pH (pH 7 > 6 > 5 > 4), regardless of the growth phase. Expression of the CagA protein varied with growth phase and pH exposure in parallel with the observed transcriptional variation. The concentration of CagA in a cell membrane-enriched fraction after growth at pH 6 was significantly higher than after growth at pH 5 or 7. We conclude that the promoterless reporter xylE is useful for studying the regulation of gene expression in H. pylori and that regulation of CagA production occurs mainly at the transcriptional level
  408. McGowan CC; Cover TL; Blaser MJ. "Helicobacter pylori and gastric acid: biological and therapeutic implications". Gastroenterology. 1996 Mar;110(3):926-938 (MEDL:8608904 #19153)       

    Helicobacter pylori is highly adapted to its unusual ecological niche in the human stomach. Urease activity permits H. pylori survival at a pH of <4 in vitro and is required for the organism to colonize in animal models. However, urease does not play an important role in the survival of the organism in a pH range between 4 and 7. Other mechanisms of pH homeostasis remain poorly understood, but preliminary studies indicate that novel proteins are produced when H.pylori cells are shifted from pH 7 to 3, and the gene encoding a P-type adenosine triphosphatase that may catalyze NH4+/H+ exchange across the cytoplasmic membrane has been cloned. Mechanisms of pH homeostasis in other enteric bacteria are reviewed and provide insight into additional pathways that may be used by H. pylori. An important adaptation of H. pylori to the gastric environment may be its ability to alter gastric acid secretion. Acute infection is associated with transient hypochlorhydria, whereas chronic infection is associated with hypergastrinemia and decreased somatostatin levels. Thus, the survival of H. pylori in the gastric environment may be attributed to both the development of specialized intrinsic defenses and the organism's ability to induce physiological alterations in the host environment
  409. Perez-Perez GI; Thiberge JM; Labigne A; Blaser MJ. "Relationship of immune response to heat-shock protein A and characteristics of Helicobacter pylori-infected patients". Journal of infectious diseases. 1996 Nov;174(5):1046-1050 (MEDL:8896507 #19141)       

    Heat-shock protein A (HspA) is a GroES homolog in Helicobacter pylori. Using a recombinant HspA-maltose-binding protein fusion, the serologic response to HspA were determined. For 139 H. pylori-uninfected persons, responses to HspA were low-level or absent. In a survey of 273 infected persons, 105 (38.5%) were seropositive; there was no relationship between clinical outcome of infection and HspA seropositivity. Using paired sera obtained from 39 subjects (mean, 7.1 years apart), the stability of seroresponsiveness to HspA was examined. For 34 persons there was no change in status between the paired sera, but 5 (20%) of 25 initially seronegative persons seroconverted. The hypothesis that HspA seropositivity was related to patient age was examined using sera from 121 asymptomatic H. pylori-infected persons. Both the HspA seropositivity rate and the intensity of the response rose with age. In total, these findings indicate that HspA seropositivity is not universal but may be a consequence of prolonged H. pylori infection
  410. Perez-Perez, Guillermo I; Blaser, Martin J. "Campylobacter and helicobacter" IN: Medical microbiology . [Galveston, Tex.] : University of Texas Medical Branch at Galveston, c1996. . p.?-?.  4th ed  (OCLC:67765263-a #5808)    
  411. Ricci V; Ciacci C; Zarrilli R; Sommi P; Tummuru MK; Del Vecchio Blanco C; Bruni CB; Cover TL; Blaser MJ; Romano M. "Effect of Helicobacter pylori on gastric epithelial cell migration and proliferation in vitro: role of VacA and CagA". Infection & immunity. 1996 Jul;64(7):2829-2833 (MEDL:8698518 #19149)    

    Helicobacter pylori infection is associated with inflammation of the gastric mucosa and with gastric mucosal damage. In this study, we sought to test the hypothesis that two H. pylori virulence factors (VacA and CagA) impair gastric epithelial cell migration and proliferation, the main processes involved in gastric mucosal healing in vivo. Human gastric epithelial cells (MKN 28) were incubated with undialyzed or dialyzed broth culture filtrates from wild-type H. pylori strains or isogenic mutants defective in production of VacA, CagA, or both products. We found that (i) VacA specifically inhibited cell proliferation without affecting cell migration, (ii) CagA exerted no effect on either cell migration or proliferation, and (iii) undialyzed H. pylori broth culture filtrates inhibited both cell migration and proliferation through a VacA- and CagA-independent mechanism. These findings demonstrate that, in addition to damaging the gastric mucosa, H. pylori products may also impair physiological processes required for mucosal repair
  412. Wirth HP; Yang M; Karita M; Blaser MJ. "Expression of the human cell surface glycoconjugates Lewis x and Lewis y by Helicobacter pylori isolates is related to cagA status". Infection & immunity. 1996 Nov;64(11):4598-4605 (MEDL:8890213 #19143)    

    Monoclonal antibodies were used in an enzyme-linked immunosorbent assay for the detection of human Lewis immunodeterminants in the lipopolysaccharide of Helicobacter pylori. In 94 H. pylori isolates, expression of Lewis(x) (Le(x)) and Le(y) was a stable phenotypic marker independent of the growth medium and cell age; 46 (49%) of the isolates expressed both and 34 (36%) of the isolates expressed either Le(x) or Le(y); 14 (15%) were negative for both determinants. Twelve (13%) isolates expressed Le(b), 3 (3%) expressed Le(a), and 2 (2%) expressed sialyl-Le(x). H. pylori isolates positive for both Le(x) and Le(y) were predominantly cagA+ (P < 0.001) and possessed the s1 signal sequence (P < 0.05) and the m1 midregion type (P = 0.033) of vacA. Isogenic mutants of H. pylori CPY3401 were created by interruption of the cagA, picB, or ureA gene. The cagA-ablated strain (but not the picB- and ureA-ablated mutant strains) had significantly (P < 0.01) diminished expression of Le(y) compared with that of the wild-type strain; for all four strains, expression of Le(x) was similar. In conclusion, 89% of H. pylori isolates express Le determinants in their lipopolysaccharide, mimicking human cell surface glycoconjugates. Strong expression of Le(x) and Le(y) by cagA+ isolates could counterbalance their enhanced proinflammatory activities and thereby facilitate persistence
  413. Zhang L; Blot WJ; You WC; Chang YS; Kneller RW; Jin ML; Li JY; Zhao L; Liu WD; Zhang JS; Ma JL; Samloff IM; Correa P; Blaser MJ; Xu GW; Fraumeni JF. "Helicobacter pylori antibodies in relation to precancerous gastric lesions in a high-risk Chinese population". Cancer epidemiology biomarkers & prevention. 1996 Aug;5(8):627-630 (MEDL:8824365 #19146)    

    Helicobacter pylori infection is a major cause of gastritis and may be a key risk factor for stomach cancer, but its role in the process of gastric carcinogenesis is not well understood. Herein, we examine H. pylori prevalence in relation to demographic and lifestyle factors and to severity of precancerous lesions in an area of China with one of the highest rates of stomach cancer in the world. H. pylori serum IgG antibody positivity was assayed among 2646 adults, ages 35-64, participating in a population-based gastroscopic screening survey in the high-risk area. The prevalence of positivity was evaluated according to gastric histology, environmental and lifestyle variables determined by interviews during the screening, and level of serum pepsinogens. The odds of advanced precancerous lesions (intestinal metaplasia and dysplasia) of the stomach among those with antibody positivity were estimated by logistic regression. Seventy-two % of the population was H. pylori antibody-positive, with nonsignificant variation by sex, age, income, education, family size, and cigarette smoking habits. H. pylori positivity was higher among those who ate sour pancakes, a fermented indigenous staple that is a risk factor for gastric dysplasia and stomach cancer in this population. The prevalence of H. pylori varied most notably, however, with gastric pathology. The percent of H. pylori positivity increased from 55 to 60 to 87% among those with superficial (nonatrophic) gastritis, mild chronic atrophic gastritis, and severe chronic atrophic gastritis, respectively, before falling to 78% among those with intestinal metaplasia or dysplasia. H. pylori antibody positivity also was strongly correlated with serum pepsinogen concentrations, particularly pepsinogen II, but knowledge of H. pylori status did not markedly improve serological identification of advanced precancerous lesions above that provided by pepsinogen ratios alone. The findings suggest that H. pylori infection contributes to the process of gastric carcinogenesis, particularly during the early stages, in this high-risk area
  414. Allos BM; Blaser MJ. "Campylobacter jejuni and the expanding spectrum of related infections". Clinical infectious diseases. 1995 May;20(5):1092-9; quiz 1100 (MEDL:7619982 #19173)       
  415. Atherton JC; Cao P; Peek RM; Tummuru MK; Blaser MJ; Cover TL. "Mosaicism in vacuolating cytotoxin alleles of Helicobacter pylori. Association of specific vacA types with cytotoxin production and peptic ulceration". Journal of biological chemistry. 1995 Jul 28;270(30):17771-17777 (MEDL:7629077 #19163)    

    Approximately 50% of Helicobacter pylori strains produce a cytotoxin, encoded by vacA, that induces vacuolation of eukaryotic cells. Analysis of a clinically isolated tox- strain (Tx30a) indicated secretion of a 93-kDa product from a 3933-base pair vacA open reading frame. Characterization of 59 different H. pylori isolates indicated the existence of three different families of vacA signal sequences (s1a, s1b, and s2) and two different families of middle-region alleles (m1 and m2). All possible combinations of these vacA regions were identified, with the exception of s2/m1 (p < 0.001); this mosaic organization implies that recombination has occurred in vivo between vacA alleles. Type s1/m1 strains produced a higher level of cytotoxin activity in vitro than type s1/m2 strains; none of 19 type s2/m2 strains produced detectable cytotoxin activity. The presence of cagA (cytotoxin-associated gene A) was closely associated with the presence of vacA signal sequence type s1 (p < 0.001). Among patients with past or present peptic ulceration, 21 (91%) of 23 harbored type s1 strains compared with 16 (48%) of 33 patients without peptic ulcers; only 2 (10%) of 19 subjects harboring type s2 strains had past or present peptic ulcers (p < 0.005). Thus, specific vacA genotypes of H. pylori strains are associated with the level of in vitro cytotoxin activity as well as clinical consequences
  416. Blaser MJ. "Intrastrain differences in Helicobacter pylori: a key question in mucosal damage?". Annals of medicine (Helsinki). 1995 Oct;27(5):559-563 (MEDL:8541032 #19160)       

    Helicobacter pylori causes persistent infection and inflammation in the human stomach, yet only a small fraction of infected people develop illness. An important question is why this diversity exists in infection outcome. In recent years, there has been evidence of substantial phenotypic as well as genotypic diversity of H. pylori. Three different phenotypes--production of vacuolating cytotoxin, presence of cagA, and ability for strong PMN activation--appear to be linked to one another and to the propensity for a H. pylori strain to cause peptic ulcer disease. Further investigation in this field may help to define which infected people bear the highest risk for serious clinical consequences, and ultimately to define optimal vaccine candidates and strategies
  417. Blaser MJ. "The role of Helicobacter pylori in gastritis and its progression to peptic ulcer disease". Alimentary pharmacology & therapeutics. 1995;9 Suppl 1(1):27-30 (MEDL:7495938 #19180)    

    Helicobacter pylori infection is now recognized as the major cause of chronic gastritis throughout the world. A fraction of infected persons develop peptic ulcer disease or gastric cancer, accounting for its clinical significance. The pathophysiology of this infection can be better understood by considering five central concepts--heterogeneity of strains, persistence of infection, immunological down-regulation, physiological consequences and variability in outcome. Microbial, host and environmental factors must each contribute to the outcome variation
  418. Blaser MJ; Chyou PH; Nomura A. "Age at establishment of Helicobacter pylori infection and gastric carcinoma, gastric ulcer, and duodenal ulcer risk". Cancer research. 1995 Feb 1;55(3):562-565 (MEDL:7834625 #19178)    

    Helicobacter pylori is an important risk factor for gastric cancer, gastric ulcer, and duodenal ulcer, yet most infected persons do not develop disease. We examined two correlates of acquisition age, sibship size and birth order, to evaluate the hypothesis that early life acquisition of H. pylori is a risk factor for the development of these illnesses. In earlier nested case-control studies of a cohort of Japanese American men in Hawaii, evidence of H. pylori infection was associated with the development of gastric cancer or gastric or duodenal ulceration during the subsequent period, 1968-1989. The present analysis included 102, 147, and 64 men who developed adenocarcinoma of the distal stomach, gastric ulcer, and duodenal ulcer, respectively, and a matched control for each. Sibship size and birth order data were analyzed as risk factors for development of these diseases. H. pylori-infected but not H. pylori-uninfected men from larger sibships (odds ratio, 2.06) and of higher birth order (odds ratio, 1.67) were at increased risk for developing gastric cancer. H. pylori- infected men but not uninfected men at higher birth order had increased risk of gastric (odds ratio, 1.64) but not duodenal ulcers. These data are consistent with the hypothesis that early life acquisition of H. pylori increases the risk of developing both gastric cancer and gastric ulcer but not duodenal ulcer
  419. Blaser MJ; Perez-Perez GI; Kleanthous H; Cover TL; Peek RM; Chyou PH; Stemmermann GN; Nomura A. "Infection with Helicobacter pylori strains possessing cagA is associated with an increased risk of developing adenocarcinoma of the stomach". Cancer research. 1995 May 15;55(10):2111-2115 (MEDL:7743510 #19171)    

    To determine whether infection with a Helicobacter pylori strain possessing cagA is associated with an increased risk of development of adenocarcinoma of the stomach, we used a nested case-control study based on a cohort of 5443 Japanese-American men in Oahu, Hawaii, who had a physical examination and a phlebotomy during 1967 to 1970. We matched 103 H. pylori-infected men who developed gastric cancer during a 21-year surveillence period with 103 H. pylori-infected men who did not develop gastric cancer and tested stored serum specimens from patients and controls for the presence of serum IgG to the cagA product of H. pylori using an ELISA. The serum IgG assay using a recombinant CagA fragment had a sensitivity of 94.4% and a specificity of 92.5% when used in a clinically defined population; serological results were stable for more than 7 years. For men with antibodies to CagA, the odds ratio of developing gastric cancer was 1.9 (95% confidence interval, 0.9-4.0); for intestinal type cancer of the distal stomach, the odds ratio was 2.3 (95% confidence interval, 1.0-5.2). Age < 72 years and advanced tumor stage at diagnosis were significantly associated with CagA seropositivity. We conclude that infection with a cagA-positive H. pylori strain in comparison with a cagA-negative strain somewhat increases the risk for development of gastric cancer, especially intestinal type affecting the distal stomach
  420. Blaser, Martin J. Epidemiology of Halicopter pylori infection. Oxford : Blackwell Science, 1995. 110 p; ; 28cm.
  421. Blaser, Martin J. Helicobacter pyloir : the second decade [Sound Recording]. [Bethesda MD : American Gastroenterological Association, 1995. 2 sound cassettes (135 min).
  422. Blaser, Martin J. Infections of the gastrointestinal tract. New York : Raven Press, 1995. xxix, 1578 p. ; 29cm.     
  423. Burucoa C; Fremaux C; Pei Z; Tummuru M; Blaser MJ; Cenatiempo Y; Fauchere JL. "Nucleotide sequence and characterization of peb4A encoding an antigenic protein in Campylobacter jejuni". Research in microbiology. 1995 Jul-Aug;146(6):467-476 (MEDL:8525063 #19164)       

    The 29-kDa protein PEB4, a major antigen of Campylobacter jejuni, is present in all C. jejuni strains tested and elicits an antibody response in infected patients. By screening a lambda gt11 library of chromosomal DNA fragments of C. jejuni strain 81-176 in Escherichia coli Y1090 cells with antibody raised against purified PEB4, a recombinant phage with a 2-kb insert expressing an immunoreactive protein of 29 kDa was isolated. DNA sequence analysis revealed that the insert contains two complete open reading frames ORF-A and ORF-B. ORF-A (peb4A) encodes a 273-residue protein with a calculated molecular mass of 30,460 daltons. The deduced amino acid sequence, composition and pl of the recombinant mature protein are similar to those determined for purified PEB4. The first 21 residues resemble a signal peptide. Gene bank searches indicated 33.7% identity with protein export protein PrsA of Bacillus subtilis and 23.8% identity with protease maturation protein precursor PrtM of Lactococcus lactis. PCR experiments indicate that peb4A is highly conserved among C. jejuni strains. ORF-B begins 2 bp after the last codon of peb4A and encodes a putative protein of 353 residues with 63.4% identity with E. coli fructose 1,6-biphosphate aldolase. The sequence arrangement suggests that these two genes form an operon
  424. Cover TL; Glupczynski Y; Lage AP; Burette A; Tummuru MK; Perez-Perez GI; Blaser MJ. "Serologic detection of infection with cagA+ Helicobacter pylori strains". Journal of clinical microbiology. 1995 Jun;33(6):1496-1500 (MEDL:7650174 #19168)    

    Approximately 60% of Helicobacter pylori isolates possess the cagA gene and express its 120- to 140-kDa product (CagA). In this study, the cagA gene was detected in H. pylori isolates from 26 (81.3%) of 32 patients with duodenal ulcers (DU), 17 (68.0%) of 25 patients with gastric ulcers, and 23 (59.0%) of 39 patients with nonulcer dyspepsia (NUD). By Western blotting (immunoblotting) with antiserum to CagA, in vitro CagA expression was demonstrated for 95.5% of cagA+ strains compared with 0% of strains lacking cagA. Sera from patients infected with cagA+ strains (n = 66) reacted with recombinant CagA in an enzyme-linked immunosorbent assay to a significantly greater extent than either sera from patients infected with strains lacking cagA (n = 30) or sera from uninfected persons (n = 25) (P < 0.001). A strain lacking cagA was isolated from eight patients who had serum immunoglobulin G antibodies to CagA, which suggests that these patients were infected with multiple strains. Serum immunoglobulin G antibodies to CagA were present in 87.5, 76.0, and 56.4% of patients with DU, gastric ulcers, and NUD, respectively (odds ratio, 5.41; 95% confidence interval, 1.44 to 24.72; P = 0.004 [DU versus NUD]). These data demonstrate an association between infection with cagA+ H. pylori and the presence of duodenal ulceration and indicate that serologic testing is a sensitive method for detecting infection with cagA+ strains
  425. Cutler AF; Havstad S; Ma CK; Blaser MJ; Perez-Perez GI; Schubert TT. "Accuracy of invasive and noninvasive tests to diagnose Helicobacter pylori infection". Gastroenterology. 1995 Jul;109(1):136-141 (MEDL:7540995 #19165)       

    BACKGROUND & AIMS: Multiple tests are available for determining Helicobacter pylori infection. Our aim was to compare the sensitivity, specificity, and negative and positive predictive value of the most widely available tests for diagnosis of H. pylori. METHODS: A total of 268 patients (mean age, 53.7 +/- 15.8 years; 142 male and 126 female; 125 white and 143 nonwhite) was tested for H. pylori infection by [13C]urea breath test (UBT), measurement of serum immunoglobulin (Ig) G and IgA antibody levels, and antral biopsy specimens for CLO test, histology, and Warthin-Starry stain. No patient received specific treatment for H. pylori before testing. The infection status for each patient was established by a concordance of test results. RESULTS: Warthin-Starry staining had the best sensitivity and specificity, although CLO test, UBT, and IgG levels were not statistically different in determining the correct diagnosis. The absence of chronic antral inflammation was the best method to exclude infection. Stratification of results by clinical characteristics showed that UBT and chronic inflammation were the best predictors of H. pylori status in patients older than 60 years of age. IgA was a better predictor in white patients. CONCLUSIONS: The noninvasive UBT and IgG serology test are as accurate in predicting H. pylori status in untreated patients as the invasive tests of CLO and Warthin-Starry
  426. Dubois A; Fiala N; Weichbrod RH; Ward GS; Nix M; Mehlman PT; Taub DM; Perez-Perez GI; Blaser MJ. "Seroepizootiology of Helicobacter pylori gastric infection in nonhuman primates housed in social environments". Journal of clinical microbiology. 1995 Jun;33(6):1492-1495 (MEDL:7650173 #19169)    

    We determined the seroepizootiology of Helicobacter pylori infection in rhesus monkeys. Plasma was obtained from 196 animals (age range, 1 to 22 years) that were housed in social environments, either in indoor gang cages, in outdoor corrals, or in free-ranging forested conditions. Plasma immunoglobulin G levels were determined with a specific enzyme-linked immunosorbent assay, and the cutoff immunoglobulin G value for H. pylori seropositivity was determined from a study of 25 monkeys whose infection status was assessed by light microscopy and culture. One-year-old animals of both genders in all housing conditions had the lowest rate of positivity (60% in monkeys 1 year old versus 81% in monkeys 2 to 10 years old, P = 0.026). In addition, females tended to have higher rates of positivity than males. Seroconversion during a 1-year observation period occurred in 7 (28%) of 25 seronegative animals. Seroreversion occurred in 3 (4%) of the 78 positive animals; all 3 of these animals had received antimicrobial agents during the year. These observations demonstrate that the epizootiology of H. pylori infection in rhesus monkeys may serve as a model for human infection
  427. Dummer JS; Perez-Perez GI; Breinig MK; Lee A; Wolff SN; Kormos R; Griffith BP; Blaser MJ. "Seroepidemiology of Helicobacter pylori infection in heart transplant recipients". Clinical infectious diseases. 1995 Nov;21(5):1303-1305 (MEDL:8589162 #19159)       

    We analyzed serum samples obtained from 100 heart transplant recipients before and after transplantation for the presence of IgG antibodies to Helicobacter pylori. Enzyme-linked immunosorbent assay revealed that 35 patients were seropositive before the procedure. Seropositive patients were older than seronegative patients, but the two groups did not differ in terms of cardiac diagnosis, gender, survival, or the number of admissions or rejection episodes. In addition, seropositive patients did not have more-frequent episodes of gastritis, ulcer disease, or gastrointestinal bleeding. Over a mean serological follow-up of 3.4 years, only one of 65 seronegative patients seroconverted. Of the 35 seropositive patients, 14 became seronegative for H. pylori a median of 194 days (range, 47-2,657 days) after transplantation. Seroreverters, as compared with serofast patients, had received more intravenous and total antibiotics during follow-up (P = .01), were more likely to have received a combination of antibiotics active against H. pylori (P < .025), and had received more antirejection treatment (P = .01). The incidence of H. pylori infection is not increased after heart transplantation, and many seropositive patients serorevert after transplantation when antibacterial and immunosuppressive agents are administered
  428. Dworkin J; Tummuru MK; Blaser MJ. "A lipopolysaccharide-binding domain of the Campylobacter fetus S-layer protein resides within the conserved N terminus of a family of silent and divergent homologs". Journal of bacteriology. 1995 Apr;177(7):1734-1741 (MEDL:7896695 #19174)    

    Campylobacter fetus cells can produce multiple S-layer proteins ranging from 97 to 149 kDa, with a single form predominating in cultured cells. We have cloned, sequenced, and expressed in Escherichia coli a sapA homolog, sapA2, which encodes a full-length 1,109-amino-acid (112-kDa) S-layer protein. Comparison with the two previously cloned sapA homologs has demonstrated two regions of identity, approximately 70 bp before the open reading frame (ORF) and proceeding 550 bp into the ORF and immediately downstream of the ORF. The entire genome contains eight copies of each of these conserved regions. Southern analyses has demonstrated that sapA2 existed as a complete copy within the genome in all strains examined, although Northern (RNA) analysis has demonstrated that sapA2 was not expressed in the C. fetus strain from which it was cloned. Further Southern analyses revealed increasing sapA diversity as probes increasingly 3' within the ORF were used. Pulsed-field gel electrophoresis and then Southern blotting with the conserved N-terminal region of the sapA homologs as a probe showed that these genes were tightly clustered on the chromosome. Deletion mutagenesis revealed that the S-layer protein bound serospecifically to the C. fetus lipopolysaccharide via its conserved N-terminal region. These data indicated that the S-layer proteins shared functional activity in the conserved N terminus but diverged in a semiconservative manner for the remainder of the molecule. Variation in S-layer protein expression may involve rearrangement of complete gene copies from a single large locus containing multiple sapA homologs
  429. Dworkin J; Tummuru MK; Blaser MJ. "Segmental conservation of sapA sequences in type B Campylobacter fetus cells". Journal of biological chemistry. 1995 Jun 23;270(25):15093-15101 (MEDL:7797493 #19166)    

    Campylobacter fetus cells may exist as either of two defined serogroups (type A or B) based on their lipopolysaccharide (LPS) composition. Wild-type strains contain surface array proteins (S-layer proteins) that have partial antigenic cross-reactivity but bind exclusively to LPS from homologous (type A or B) cells. Type A cells possess 8 homologs of sapA, which encodes a 97-kDa S-layer protein; the gene products of these homologs have a conserved N terminus of 184 amino acids. To further explore the structural relationships between the C. fetus S-layer proteins and their encoding genes, we sought to clone and express an S-layer protein from type B strain 84-91. The cloned type B gene (sapB) was similar in structure to the previously cloned type A gene (sapA) and encoded a full-length 936-amino acid (97-kDa) S-layer protein. Sequence analysis of sapB indicated that the conserved N-terminal encoding region in sapA was absent but that the remainder of the ORF (encoding 751 amino acids) was identical to that of sapA in spite of the nonconserved nature of this region among sapA homologs. Noncoding sequences both 300 base pairs 5' and 1000 base pairs 3' to the sapB and sapA ORFs, including the sapA promoter and transcriptional terminator sequences, were essentially identical. Southern analyses revealed that the sapB N-terminal encoding region was conserved in multiple copies in type B strains but was absent in type A strains. Recombinant sapA and sapB products bound to a substantially greater degree to cells of the homologous LPS type compared with the heterologous LPS type, indicating that the conserved sapA- and sapB-encoded N termini are critical for LPS binding specificity. The parallel genetic organization and identity at the nucleotide level in both coding and noncoding regions for sap homologs in types A and B cells indicates the necessity of both homolog conservation and high fidelity DNA replication in the biology of sap diversity
  430. Garcia MM; Lutze-Wallace CL; Denes AS; Eaglesome MD; Holst E; Blaser MJ. "Protein shift and antigenic variation in the S-layer of Campylobacter fetus subsp. venerealis during bovine infection accompanied by genomic rearrangement of sapA homologs". Journal of bacteriology. 1995 Apr;177(8):1976-1980 (MEDL:7721688 #19177)    

    Campylobacter fetus subsp. venerealis isolated from a case of human vaginosis was inoculated into the uterus of a C. fetus-negative heifer. Isolates obtained weekly from the vaginal mucus exhibited variations in high-molecular-mass-protein profiles from that of the original inoculum, which had a dominant 110-kDa S-layer protein. Immunoblots of the weekly isolates with monoclonal antibody probes against the 110-kDa S-layer protein and other C. fetus S-layer proteins demonstrated antigenic shifts. Genomic digests of the isolates probed with a 75-mer oligonucleotide of the conserved sapA region also indicated that antigenic variation of the S-layer is accompanied by DNA rearrangement
  431. Ghiara P; Marchetti M; Blaser MJ; Tummuru MK; Cover TL; Segal ED; Tompkins LS; Rappuoli R. "Role of the Helicobacter pylori virulence factors vacuolating cytotoxin, CagA, and urease in a mouse model of disease". Infection & immunity. 1995 Oct;63(10):4154-4160 (MEDL:7558333 #19161)    

    The pathogenic role of Helicobacter pylori virulence factors has been studied with a mouse model of gastric disease. BALB/c mice were treated orally with different amounts of sonic extracts of cytotoxic H. pylori strains (NCTC 11637, 60190, 84-183, and 87A300 [CagA+/Tox+]). The pathological effects on histological sections of gastric mucosae were assessed and were compared with the effects of treatments with extracts from noncytotoxic strains (G21 and G50 [CagA-/Tox-]) and from strains that express either CagA alone (D931 [CagA+/Tox-]) or the cytotoxin alone (G104 [CagA-/Tox+]). The treatment with extracts from cytotoxic strains induced various epithelial lesions (vacuolation, erosions, and ulcerations), recruitment of inflammatory cells in the lamina propria, and a marked reduction of the mucin layer. Extracts of noncytotoxic strains induced mucin depletion but no other significant pathology. Crude extracts of strain D931, expressing CagA alone, caused only mild infiltration of inflammatory cells, whereas extracts of strain G104, expressing cytotoxin alone, induced extensive epithelial damage but little inflammatory reaction. Loss of the mucin layer was not associated with a cytotoxic phenotype, since this loss was observed in mice treated with crude extracts of all strains. The pathogenic roles of CagA, cytotoxin, and urease were further assessed by using extracts of mutant strains of H. pylori defective in the expression of each of these virulence factors. The results obtained suggest that (i) urease activity does not play a significant role in inducing the observed gastric damage, (ii) cytotoxin has an important role in the induction of gastric epithelial cell lesions but not in eliciting inflammation, and (iii) other components present in strains which carry the cagA gene, but distinct from CagA itself, are involved in eliciting the inflammatory response
  432. Ho TW; Mishu B; Li CY; Gao CY; Cornblath DR; Griffin JW; Asbury AK; Blaser MJ; McKhann GM. "Guillain-Barre syndrome in northern China. Relationship to Campylobacter jejuni infection and anti-glycolipid antibodies". Brain. 1995 Jun;118 ( Pt 3)(6):597-605 (MEDL:7600081 #19170)       

    Guillain-Barre syndrome has been considered to be primarily an acute inflammatory demyelinating polyneuropathy (AIDP). Our experience with Guillain-Barre syndrome in northern China differs from the traditional concept. Electrophysiologically and pathologically, most of our patients have motor axonal degeneration with minimal cellular inflammation, which we have termed 'acute motor axonal neuropathy' (AMAN). The current studies were undertaken to characterize prospectively the clinical, electrophysiological, and serological features of Guillain-Barre syndrome, defined clinically, in northern China. In 1991 and 1992, we characterized by electrodiagnostic criteria 129 Chinese patients with Guillain-Barre syndrome. The AMAN form was present in 65% of patients, the AIDP form in 24% and 11% were unclassifiable. For the 38 patients who presented from January to October, 1992, we performed serological assays for antibodies to Campylobacter jejuni and to glycolipids. Of these 38 patients, 55% had AMAN, 32% had AIDP and 13% were unclassifiable. Sixty-six percent of the 38 had serological evidence of recent C. jejuni infection as compared with 16% of village controls (P = 0.001). Seventy-six percent of AMAN patients and 42% of AIDP patients were seropositive. IgG anti-GM1 antibodies were more frequent in Guillain-Barre syndrome patients compared with village controls (42% versus 6%; P < 0.01). However, no statistically significant correlations were found between the pattern of disease, AMAN or AIDP, anti-glycolipid antibodies, or C. jejuni antibodies. Based on electrophysiological criteria, Guillain-Barre syndrome in northern China can be divided into two predominant forms: AIDP and AMAN. The AMAN form is more common and predominates in the yearly summer outbreaks of Guillain-Barre syndrome.(ABSTRACT TRUNCATED AT 250 WORDS)
  433. Kirschner DE; Blaser MJ. "The dynamics of Helicobacter pylori infection of the human stomach". Journal of theoretical biology. 1995 Sep 21;176(2):281-290 (MEDL:7475116 #19162)       

    Helicobacter pylori is a bacterial pathogen of the gastrointestinal tract of humans causing chronic superficial gastritis which persists for decades. The mechanism by which H. pylori is able to persist, despite environmental constraints, remains unknown. Therefore, a model is proposed describing the interactions of H. pylori with its host, involving an autoregulatory network in which inflammation leads to nutrient release. A determinist mathematical model examining the interactions necessary to maintain chronic infection indicates that this proposed autoregulatory network can produce steady-state solutions, and the model is robust in encompassing biological variations
  434. Kuipers EJ; Perez-Perez GI; Meuwissen SG; Blaser MJ. "Helicobacter pylori and atrophic gastritis: importance of the cagA status". Journal of the National Cancer Institute. 1995 Dec 6;87(23):1777-1780 (MEDL:7473834 #19157)       

    BACKGROUND: Infection with Helicobacter pylori is a major risk factor for the development of atrophic gastritis and gastric cancer. H. pylori strains can differ with respect to the presence of cagA (cytotoxin-associated gene A), a gene encoding a high-molecular-weight immunodominant antigen. H. pylori strains possessing cagA have been associated with enhanced induction of acute gastric inflammation. PURPOSE: We investigated the relationship between cagA status and the development of atrophic gastritis in a cohort of subjects infected with H. pylori. METHODS: Gastrointestinal endoscopy with biopsy sampling was used to study the natural history of gastritis in 58 subjects infected with H. pylori. Biopsy specimens were obtained before and after a mean follow-up period of 11.5 years (range, 10-13 years). The cagA status of each individual was determined at the follow-up visit with the use of an enzyme-linked immunosorbent assay designed to detect the presence of serum immunoglobulin G directed against the CagA protein. Two-sided Fisher's exact tests, McNemar's tests, Student's t tests, and Wilcoxon sum rank tests were used to analyze the data. RESULTS: Twenty-four (41%) of the 58 evaluated subjects had serum antibodies against CagA (i.e., they were cagA positive), and 34 subjects were cagA negative. At the initial visit, moderate to severe atrophic gastritis was observed in eight (33%) of the cagA-positive subjects and in six (18%) of the cagA-negative subjects. At that time, positive cagA status and gastric atrophy were not significantly related (P = .22; Fisher's exact test; odds ratio [OR] 2.33; 95% confidence interval [CI] = 0.58-9.65). During follow-up, 16 (36%) of the 44 initially atrophy-negative subjects developed atrophic gastritis (eight [50%] of 16 cagA-positive subjects versus eight [29%] of 28 cagA-negative subjects; P = .20, Fisher's exact test; relative risk [RR] = 1.75; 95% CI = 0.82-3.76). In six of these 16 subjects (five cagA positive versus one cagA negative), atrophic gastritis was accompanied by the development of intestinal metaplasia (i.e., a change in the type of specialized cells present) (P = .02; Fisher's exact test; RR = 9.06; 95% CI = 1.16-71.0). One of the initially atrophy-negative, cagA-positive subjects developed early gastric cancer. Four (29%) of the 14 subjects initially diagnosed with atrophic gastritis showed regression of atrophy during follow-up (one cagA positive and three cagA negative). Therefore, at the end of follow-up, 15 (62%) of the 24 cagA-positive subjects had atrophic gastritis compared with 11 (32%) of the 34 cagA-negative subjects (P = .02; Fisher's exact test; OR = 3.48; 95% CI = 1.02-12.18). CONCLUSION: Infection with cagA-positive H. pylori strains is associated with an increased risk for the eventual development of atrophic gastritis and intestinal metaplasia
  435. Marrie TJ; Purdy RA; Johnston BL; McCormick CW; Benstead T; Ansell J; Maloney W; Allos BM; Blaser MJ. "Encephalomyeloradiculopathy of infectious or parainfectious etiology--a new entity?". Clinical infectious diseases. 1995 Apr;20(4):945-953 (MEDL:7795099 #19176)       

    Between 19 March 1990 and 24 December 1992, six persons in Nova Scotia presented with a unique neurological illness. A prodrome of fever and headache was followed by neurogenic bladder, transverse myelitis, and encephalopathy in association with mononuclear pleocytosis of the CSF and nerve-conduction study findings consistent with polyradiculopathy. The spinal cords of three of the patients appeared abnormal on myelograms or magnetic resonance imaging studies. No microbial agent was isolated or demonstrated serologically. All of the patients were treated with antimicrobial agents and corticosteroids. Three recovered completely, but neurogenic bladder persisted in the remaining three. We suggest that this group of patients manifested an encephalomyeloradiculopathy that is likely a new clinical entity of infectious or parainfectious etiology
  436. Peek RM; Miller GG; Tham KT; Perez-Perez GI; Cover TL; Atherton JC; Dunn GD; Blaser MJ. "Detection of Helicobacter pylori gene expression in human gastric mucosa". Journal of clinical microbiology. 1995 Jan;33(1):28-32 (MEDL:7699060 #19179)    

    Mucosal and systemic immunologic recognition of cagA by Helicobacter pylori-infected individuals is associated with peptic ulcer disease; however, in the laboratory, expression of cagA is subject to artificial conditions which may not accurately reflect the conditions in host tissues. Gastric antral and body biopsy specimens and serum for anti-H. pylori immunoglobulin G serology were obtained from 42 patients. Biopsy specimens were studied by histology, culture, and reverse transcription PCR (RT-PCR). Oligonucleotide primers specific for H. pylori (16S rRNA, ureA, and cagA) were used to detect bacterial mRNA in gastric biopsy specimens. PCR was performed on DNA from corresponding H. pylori isolates to detect genomic 16S rRNA, ureA, and cagA. Of the 42 patients from whom clinical specimens were obtained, 25 were infected with H. pylori on the basis of both serology and histology or culture (i.e., tissue positive); 13 were negative by serology, histology, and culture; and 4 were positive by serology only. RT-PCR with 16S rRNA primers detected 24 of 25 tissue-positive and 0 of 17 tissue-negative patients (P < 0.001). RT-PCR with ureA primers detected 16 of 25 tissue-positive and 0 of 17 tissue-negative patients (P < 0.001). CagA mRNA was detected by RT-PCR in 14 of 25 gastric biopsy specimens in the tissue-positive group and in 0 of 17 gastric biopsy specimens in the tissue-negative group. PCR of genomic DNA for the presence of the cagA gene in the corresponding bacterial isolates correlated absolutely with cagA gene expression in gastric tissue. These results indicate that RT-PCR is a sensitive and specific method for the detection of the presence of H. pylori and the expression of H. pylori genes in human gastric tissue. Detection of H. pylori gene expression in vivo by this approach may contribute to improving the diagnosis and understanding the pathogenesis of H. pylori infections
  437. Peek RM; Miller GG; Tham KT; Perez-Perez GI; Zhao X; Atherton JC; Blaser MJ. "Heightened inflammatory response and cytokine expression in vivo to cagA+ Helicobacter pylori strains". Laboratory investigation. 1995 Dec;73(6):760-770 (MEDL:8558837 #19156)    

    BACKGROUND: Helicobacter pylori strains that possess the cytotoxin-associated gene (cagA) are highly associated with peptic ulcer disease, but the role of cagA in pathogenesis is unknown. EXPERIMENTAL DESIGN: To test the hypothesis that cagA+ stains elicit a greater proinflammatory cytokine response in the gastric mucosa than cagA- strains, gastric biopsies were obtained from 52 patients and studied by histology, culture, enzyme-linked immunosorbent assay, and reverse transcription polymerase chain reaction. RESULTS: Of 52 patients, 32 (62%) were infected with H. pylori based upon both serology and histology or culture, 16 (31%) were negative by serology, histology, and culture, and four (7%) were positive by serology only. Of 15 H. pylori-infected patients with peptic ulceration, 14 (92%) were infected with cagA+ strains compared with 8 (50%) of 16 patients with gastritis alone, and those infected with cagA+ strains had significantly higher grades of inflammation in the gastric mucosa. Antral inflammation score was significantly associated with IL-8 production. Antral biopsies from infected patients, compared with uninfected patients, significantly more often demonstrated IL-1 beta, IL-2, and IL-8 expression, and those infected with cagA+ compared with cagA- strains significantly more often expressed IL-1 alpha and IL-1 beta and showed elevated antral IL-8 protein levels. Similarly, patients with ulcer disease significantly more often expressed antral IL-1 alpha and IL-8 than those without ulceration. CONCLUSION: These results indicate that infection with cagA+ H. pylori strains is associated with higher grades of gastric inflammation, correlating with enhanced mucosal levels of IL-8, and increased risk of peptic ulceration
  438. Perez-Perez GI; Shepherd VL; Morrow JD; Blaser MJ. "Activation of human THP-1 cells and rat bone marrow-derived macrophages by Helicobacter pylori lipopolysaccharide". Infection & immunity. 1995 Apr;63(4):1183-1187 (MEDL:7890370 #19175)    

    The mechanism by which Helicobacter pylori, which has little or no invasive activity, induces gastric-tissue inflammation and injury has not been well characterized. We have previously demonstrated that water-extracted proteins of H. pylori are capable of activating human monocytes by a lipopolysaccharide (LPS)-independent mechanism. We have now compared activation of macrophages by purified LPS from H. pylori and from Escherichia coli. LPS was prepared by phenol-water extraction from H. pylori 88-23 and from E. coli O55. THP-1, a human promyelomonocytic cell line, and macrophages derived from rat bone marrow each were incubated with the LPS preparations, and cell culture supernatants were assayed for production of tumor necrosis factor alpha (TNF-alpha), prostaglandin E2 (PGE2), and nitric oxide. THP-1 cells showed maximal activation by the LPS molecules after cell differentiation was induced by phorbol 12-myristate 13-acetate. Maximal TNF-alpha and PGE2 production occurred by 6 and 18 h, respectively, in both types of cells. In contrast, NO was produced by rat bone marrow-derived macrophages only and was maximal at 18 h. The minimum concentration of purified LPS required to induce TNF-alpha, PGE2, and NO responses in both types of cells was 2,000- to 30,000-fold higher for H. pylori than for E. coli. Purified LPS from three other H. pylori strains with different polysaccharide side chain lengths showed a similarly low level of activity, and polymyxin B treatment markedly reduced activity as well, suggesting that activation was a lipid A phenomenon. These results indicate the low biological activity of H. pylori LPS in mediating macrophage activation
  439. Sharma SA; Tummuru MK; Miller GG; Blaser MJ. "Interleukin-8 response of gastric epithelial cell lines to Helicobacter pylori stimulation in vitro". Infection & immunity. 1995 May;63(5):1681-1687 (MEDL:7729872 #19172)    

    Gastric infection with Helicobacter pylori activates a mucosal inflammatory response by mononuclear cells and neutrophils that includes expression of cytokines interleukin-1 beta (IL-1 beta), IL-6, tumor necrosis factor alpha, and IL-8. In this study, we analyzed the IL-8 response of human gastric cancer cell lines (Kato III, AGS, and MKN28) to H. pylori infection in vitro. IL-8 mRNA expression was detected by reverse transcription-PCR amplification of RNA extracted from epithelial cells after incubation with different H. pylori wild-type and mutant strains, and IL-8 secretion was measured by an enzyme-linked immunosorbent assay. Exposure to viable H. pylori induced IL-8 mRNA and protein synthesis in all three gastric cell lines but not in nongastric epithelial cell lines. Heat-killed H. pylori and a crude cytotoxin preparation did not induce significant IL-8 secretion. IL-8 mRNA peaked between 2 and 4 h postinfection, and IL-8 protein production was maximal 24 h postinfection. Exposure of gastric carcinoma cells to other gastrointestinal bacteria, such as Pseudomonas aeruginosa, Campylobacter jejuni, and Escherichia coli, but not Campylobacter fetus, induced IL-8 synthesis. Wild-type strains that expressed the vacuolating cytotoxin (Tox+) and a cytotoxin-associated gene (cagA) product (CagA+) induced significantly more IL-8 than did CagA- Tox- strains. However, there was no decrease in IL-8 induction by isogenic mutants of CagA-, Tox-, or Cag- Tox- strains or by a mutant lacking the urease subunits. These results indicate that exposure to H. pylori and other gram-negative organisms that do not colonize the gastric mucosa induces IL-8 production by gastric carcinoma cells in vitro. Although the CagA+ Tox+ phenotype of H. pylori is associated with enhanced IL-8 production by gastric cell lines, other bacterial constituents are clearly essential
  440. Thompson SA; Blaser MJ. "Isolation of the Helicobacter pylori recA gene and involvement of the recA region in resistance to low pH". Infection & immunity. 1995 Jun;63(6):2185-2193 (MEDL:7768597 #19167)    

    To understand the potential roles of the important DNA repair protein RecA in Helicobacter pylori pathogenesis, we cloned the recA gene from H. pylori 84-183. Degenerate PCR primers based on conserved RecA protein regions were used to amplify a portion of H. pylori recA, which was used as a probe to isolate the full-length recA gene from H. pylori genomic libraries. The H. pylori recA gene encoded a protein of 347 amino acids with a molecular mass of 37.6 kDa. As expected, H. pylori RecA was highly similar to other RecA proteins and most closely resembled that of Campylobacter jejuni (75% identity). Immediately downstream of recA was an open reading frame whose predicted product showed 58% identity to the Bacillus subtilis enolase protein. recA and eno were disrupted in H. pylori 84-183 by insertion of antibiotic resistance genes. Reverse transcription-PCR demonstrated that recA and eno were cotranscribed and that insertion of the kanamycin resistance gene into recA had polar effects on expression of the downstream eno. The H. pylori recA mutants were severely impaired in their ability to survive treatment with UV light and methyl methanesulfonate and with the antimicrobial agents ciprofloxacin and metronidazole. The eno mutant had sensitivities to UV light and metronidazole intermediate to those of wild-type and recA strains, suggesting that truncation of the recA-eno transcript resulted in lowered recA expression. For survival at low pH, a recA mutant was approximately 10-fold more sensitive than strain 84-183, while the eno mutant demonstrated intermediate susceptibility. This difference occurred in the presence or absence of urea, implying the involvement of a gene in the recA region in an acid resistance mechanism distinct from that mediated by urease
  441. Tummuru MK; Sharma SA; Blaser MJ. "Helicobacter pylori picB, a homologue of the Bordetella pertussis toxin secretion protein, is required for induction of IL-8 in gastric epithelial cells". Molecular microbiology. 1995 Dec;18(5):867-876 (MEDL:8825091 #19158)       

    Approximately 60% of Helicobacter pylori strains are cagA+ and this genotype is more frequently associated with duodenal ulcer disease. Although most wild-type cagA+ strains are both cytotoxigenic and induce enhanced Interleukin-8 (IL-8) secretion in gastric epithelial cells, isogenic cagA- mutants retain full activity in these assays; thus, cagA appears to be a marker of enhanced virulence. Delineation of the nucleotide sequence of a 4 kb region upstream of cagA allowed the identification of 966 bp (picA) and 2655 bp (picB) open reading frames encoding 36 kDa and 101 kDa polypeptides, respectively. picA and picB constitute an operon in opposite orientation to cagA. The deduced picB product showed significant homology (26% identity and 50% similarity) with the Bordetella pertussis toxin secretion protein (PtlC). Of 55 H. pylori clinical isolates, the picA and picB segment was conserved exclusively in cagA+ strains and present in all isolates from patients with duodenal ulceration, versus 59% of isolates from patients with gastritis alone (P = 0.01). Using gene-replacement techniques, we constructed picA and picB mutant H. pylori strains and demonstrated that the picB gene product is involved in the induction of IL-8 expression in gastric epithelial cells. Further, Northern blot hybridization and RT-PCR data showed that picA and picB are co-transcribed and an insertional mutation in picA ablates picB expression. These studies indicate a role of picA and picB in the induction of an inflammatory response in gastric epithelial cells either directly or by enabling secretion of an unidentified product, and suggest a mechanism for the overrepresentation of strains possessing these genes in patients with peptic ulceration
  442. Allos BM; Blaser MJ. "Campylobacter jejuni infection and the Guillain-Barre syndrome: mechanisms and implications". Zentralblatt fur bakteriologie. 1994 Nov;281(4):544-548 (MEDL:7727903 #19183)    
  443. Blaser MJ. "Helicobacter pylori phenotypes associated with peptic ulceration". Scandinavian journal of gastroenterology. Supplement. 1994;205(1):1-5 (MEDL:7863235 #19200)    

    Persistent infection with Helicobacter pylori occurs in a large percentage of the population, particularly in countries with low socioeconomic status. Such infection nearly always produces chronic gastric inflammation, although in most individuals it is clinically silent and only a minority of infected persons develop H. pylori-induced peptic ulcers. In this review, the hypothesis that diversity among H. pylori strains is at least partly responsible for the observed variability in the outcome of infection is explored. To date, four phenotypes that vary among H. pylori strains have been identified: variations in lipopolysaccharide structure; expression of the cagA-encoded product; production of a vacuolating cytotoxin, and enhanced activation of neutrophils. These phenotypes are associated with one another, with enhanced tissue inflammation, and with peptic ulceration, suggesting that H. pylori strain characteristics have an important influence on the clinical outcome of H. pylori infection
  444. Blaser MJ; Parsonnet J. "Parasitism by the "slow" bacterium Helicobacter pylori leads to altered gastric homeostasis and neoplasia". Journal of clinical investigation. 1994 Jul;94(1):4-8 (MEDL:8040281 #19186)       
  445. Blaser MJ; Wang E; Tummuru MK; Washburn R; Fujimoto S; Labigne A. "High-frequency S-layer protein variation in Campylobacter fetus revealed by sapA mutagenesis". Molecular microbiology. 1994 Nov;14(3):453-462 (MEDL:7885229 #19182)       

    Campylobacter fetus utilizes paracrystalline surface (S-) layer proteins that confer complement resistance and that undergo antigenic variation to facilitate persistent mucosal colonization in ungulates. C. fetus possesses multiple homologues of sapA, each of which encode full-length S-layer proteins. Disruption of sapA by a gene targeting method (insertion of kanamycin (km) resistance) caused the loss of C. fetus cells bearing full-length S-layer proteins and their replacement by cells bearing a 50 kDa truncated protein that was not exported to the cell surface. After incubation of the mutants with serum, the survival rate was approximately 2 x 10(-2). Immunoblots of survivors showed that phenotypic reversion involving high-level production of full-length (98, 127 or 149 kDa) S-layer proteins had occurred. Revertants were serum resistant but caused approximately 10-fold less bacteraemia in orally challenged mice than did the wild-type strain. Southern hybridizations of the revertants showed rearrangement of sapA homologues and retention of the km marker. These results indicate that there exists high-frequency generation of C. fetus sapA antigenic variants, and that intracellular mechanisms acting at the level of DNA reciprocal recombination play key roles in this phenomenon
  446. Carmel R; Perez-Perez GI; Blaser MJ. "Helicobacter pylori infection and food-cobalamin malabsorption". Digestive diseases & sciences. 1994 Feb;39(2):309-314 (MEDL:8313813 #19197)       

    Two entities of considerable recent interest, Helicobacter pylori infection of the stomach and food-cobalamin malabsorption, are each intimately associated with gastric abnormalities. A possible connection between the two entities thus suggested itself and prompted us to study 98 subjects with low serum cobalamin levels but normal Schilling test results and 17 controls with normal cobalamin levels. Food-cobalamin absorption was measured with the egg yolk-cobalamin absorption test (EYCAT) and was abnormal in 56 of the 115 subjects. IgG antibody to H. pylori was found in 78% of the 27 patients with severe food-cobalamin malabsorption (EYCAT < 1.0% excretion), compared with only 45% of 29 subjects with mild malabsorption (EYCAT 1.0-1.99%) and 42% of 59 subjects with normal absorption (EYCAT > or = 2.0%) (chi 2 = 9.52, P < 0.01). Antibody-positive patients had lower EYCAT excretion values than those without antibody (2.03 +/- 1.83% vs 3.11 +/- 2.13%, t = 2.913, P = 0.005). While Hispanic patients tended to malabsorb food cobalamin more frequently than did white or black patients, and men were more often antibody-positive than women, race, sex, or age characteristics were not responsible for the significant association between serologic evidence of H. pylori infection and severe malabsorption of food cobalamin. The association that we describe suggests that gastritis induced by H. pylori predisposes to a more severe form of food-cobalamin malabsorption, among its other effects on gastric status
  447. Cover TL; Tummuru MK; Cao P; Thompson SA; Blaser MJ. "Divergence of genetic sequences for the vacuolating cytotoxin among Helicobacter pylori strains". Journal of biological chemistry. 1994 Apr 8;269(14):10566-10573 (MEDL:8144644 #19194)    

    Approximately 50% of Helicobacter pylori isolates produce a cytotoxin in vitro that induces vacuolation of eukaryotic cells. Screening a lambda ZapII library of H. pylori 60190 chromosomal fragments permitted the identification of a 3864-base pair (bp) open reading frame (vacA) that encoded the vacuolating cytotoxin, and a > or = 567-bp upstream gene that was homologous to Escherichia coli cysteinyl-tRNA synthetase. The sequence data suggest that a 33-amino-acid leader sequence and a C-terminal peptide are cleaved from a 139-kDa protoxin to yield the mature 87-kDa cytotoxin. The vacA gene product contains a C-terminal motif that is present in several other bacterial proteins that undergo C-terminal cleavage, including IgA proteases of Haemophilus influenzae and Neisseria gonorrhoeae. Isogenic H. pylori mutants with insertional mutation of the vacA gene lacked vacuolating cytotoxin activity and failed to produce the 87-kDa protein. Southern analysis of naturally occurring tox-H. pylori strains with vacA probes indicated the presence of hybridizing bands, but both Southern analysis and polymerase chain reaction studies suggested that the vacA sequences of tox- strains differed from those of tox+ strains. Sequence analysis of a 1541-bp region of polymerase chain reaction-amplified vacA from tox- strain 87-203 indicated 64.8% amino acid identity with the corresponding region from tox+ strain 60190. Thus, sequence divergence in vacA genes may explain the lack of functionally active cytotoxin production by some H. pylori isolates
  448. Dubois A; Fiala N; Heman-Ackah LM; Drazek ES; Tarnawski A; Fishbein WN; Perez-Perez GI; Blaser MJ. "Natural gastric infection with Helicobacter pylori in monkeys: a model for spiral bacteria infection in humans". Gastroenterology. 1994 Jun;106(6):1405-1417 (MEDL:8194685 #19190)    

    BACKGROUND/AIMS: There is no generally accepted model for Helicobacter pylori infection in humans. The aim of this study was to examine the natural history and effect of treatment in rhesus monkeys and sequentially define the immune response to H. pylori in relation to treatment. METHODS: Infection and gastritis were graded blindly by histological analysis and culture of biopsy specimens harvested during gastroduodenoscopies in 26 anesthetized colony-bred monkeys. Plasma H. pylori-specific immunoglobulin (Ig) G levels were determined by enzyme-linked immunosorbent assay. RESULTS: H. pylori and Gastrospirilum hominis-like organisms were present in 13 and 9 monkeys, respectively; 3 animals harbored both organisms, whereas 4 monkeys were not infected. Gastritis score was < or = 1.5 in animals uninfected or infected only with G. hominis-like organisms and > or = 2.0 in all H. pylori-infected animals. IgG ratios were > or = 0.5 in 12 of 13 H. pylori-infected animals and in 2 of 13 H. pylori-negative animals (P < 0.001). One monkey became infected with H. pylori during the observation period, with concurrent increase of gastritis and plasma IgG levels. In untreated animals, infection, gastritis, and plasma IgG levels remained unchanged over 7-15 months. Triple therapy eradicated H. pylori at 6 months in 4 of 6 animals while suppressing gastritis and plasma IgG levels. CONCLUSIONS: Rhesus monkeys harboring H. pylori are persistently infected and have gastritis and elevated specific IgG levels, all of which may respond to appropriate therapy, whereas G. hominis infection is associated with little inflammation
  449. Fujimoto S; Marshall B; Blaser MJ. "PCR-based restriction fragment length polymorphism typing of Helicobacter pylori". Journal of clinical microbiology. 1994 Feb;32(2):331-334 (MEDL:7908671 #19198)    

    We applied a molecular typing approach for Helicobacter pylori that uses restriction fragment length polymorphism (RFLP) analyses of an 820-bp PCR-amplified portion of the ureC gene in H. pylori. The PCR products were digested with restriction enzyme HhaI, MboI, or MseI, and the fragments generated were analyzed by agarose electrophoresis. Among 25 independent clinical isolates, each showed a different pattern when a combination of the three RFLP patterns was used. Using this method, we studied isolates from the antrum or the body of the stomach of 14 patients before and after antibiotic therapy. Before treatment, successful isolation of H. pylori from the two sites of the stomach was possible for 12 of the 14 patients. For 10 of these 12 patients, each pair of isolates had identical RFLP profiles. For the other two patients (16.7%), however, isolates from the antrum and the body of the stomach had different RFLP profiles. Treatment was successful for 6 of the 14 patients; of the 8 patients with treatment failures, 5 had identical isolate pairs. In each case, the isolates found posttreatment were the same as the pretreatment isolates. For one of the patients who was colonized with two different isolates pretreatment, one of the isolates was identified at both sites after unsuccessful treatment. We also studied six long-term follow-up patients who had sequential biopsies at intervals of up to 5 months. Each follow-up isolate from each patient had the same RFLP profile as the initial isolate.(ABSTRACT TRUNCATED AT 250 WORDS)
  450. Gootz TD; Perez-Perez GI; Clancy J; Martin BA; Tait-Kamradt A; Blaser MJ. "Immunological and molecular characterization of Helicobacter felis urease". Infection & immunity. 1994 Mar;62(3):793-798 (MEDL:8112850 #19196)    

    Urease activity has recently been shown to be an important virulence determinant for Helicobacter pylori, allowing it to survive the low pH of the stomach during colonization. Experimental murine infection with Helicobacter felis is now being used as a model for H. pylori infection to study the effects of vaccines, antibiotics, and urease inhibitors on colonization. However, little information comparing the ureases of H. felis and H. pylori is available. Urease was partially purified from the cell surface of H. felis ATCC 49179 by A-5M agarose chromatography, resulting in an eightfold increase in specific activity over that of crude urease. The apparent Km for urea for the partially purified urease was 0.4 mM, and the enzyme was inhibited in a competitive manner by flurofamide (50% inhibitory concentration = 0.12 microM). Antiserum to whole cells of H. pylori recognized both H. pylori and H. felis urease B subunits. Antiserum raised against H. felis whole cells recognized the large and small autologous urease subunits and the cpn60 heat shock molecule in both H. felis and H. pylori. However, this antiserum showed only a weak reaction with the B subunit of H. pylori urease. Two oligomeric DNA sequences were used as probes to evaluate the relatedness of H. felis and H. pylori urease gene sequences. One 30-mer from the ureA sequence, which had been shown previously to be specific for H. pylori, failed to hybridize to H. felis genomic DNA. A probe to the putative coding sequence for the active site of the H. pylori ureB subunit hybridized at low intensity to a 2.8-kb fragment of BamHI-HindIII-digested H. felis DNA, suggesting that the sequences were homologous but not identical, a result confirmed from the recently published sequences of ureA and ureB from H. felis
  451. Harley WB; Blaser MJ. "Disseminated coccidioidomycosis associated with extreme eosinophilia". Clinical infectious diseases. 1994 Apr;18(4):627-629 (MEDL:8038321 #19195)       

    Primary coccidioidomycosis is frequently accompanied by eosinophilia in the range of 5%-10% of the peripheral white blood cell count. Dissemination of Coccidioides immitis to organs such as skin, bone, joints, and CNS usually is associated with risk factors such as sex (male), race (non-Caucasian), pregnancy, and immunosuppression. We report a case of coccidioidomycosis in an otherwise healthy African-American man with 72% eosinophilia who had dissemination to the skin, and we review cases in the literature of disseminated disease associated with eosinophilia. Marked eosinophilia may be an important early clue that dissemination of coccidioidomycosis has occurred
  452. McGowan CC; Cover TL; Blaser MJ. "The proton pump inhibitor omeprazole inhibits acid survival of Helicobacter pylori by a urease-independent mechanism". Gastroenterology. 1994 Nov;107(5):1573-1578 (MEDL:7926527 #19181)    

    BACKGROUND/AIMS: Omeprazole, a benzimidazole proton pump inhibitor, has an antibacterial effect against Helicobacter pylori at neutral pH and inhibits its urease activity. The aim of this study was to characterize H. pylori acid resistance and to determine whether omeprazole effects its survival at low pH. METHODS: We studied survival of H. pylori and other enteric organisms in buffered solutions (pH 2-7) in the presence or absence of 10 mmol/L urea and/or omeprazole. RESULTS: In the absence of urea, the acid tolerances of wild-type H. pylori, a urease-negative H. pylori mutant, Escherichia coli, and Proteus mirabilis were similar. In the presence of urea, the survival of the wild-type H. pylori at pH 2 was significantly greater than that of the other organisms. Omeprazole (100 micrograms/mL) had a marked inhibitory effect on the survival of both wild-type and urease-negative H. pylori at low pH, and similar effects on E. coli, P. mirabilis, and Salmonella typhimurium. CONCLUSIONS: Whereas survival of H. pylori below pH 4 is urease dependent, H. pylori uses non-urease-mediated mechanisms at or above pH 4. Omeprazole inhibits the survival of H. pylori at low pH through a mechanism independent of its effect on urease, an antibacterial effect that extends to other enteric bacteria
  453. McGowan CC; Cover TL; Blaser MJ. "The proton pump inhibitor omeprazole inhibits acid survival of Helicobacter pylori by a urease-independent mechanism". Gastroenterology. 1994 Sep;107(3):738-743 (MEDL:8076759 #19184)       
  454. Mishu B; Blaser MJ. "Campylobacter jejuni, human immunodeficiency virus, and the Guillain-Barre syndrome [Letter]". Journal of infectious diseases. 1994 May;169(5):1177-1177 (MEDL:8169419 #19192)       
  455. Mishu B; Blaser MJ. "Do you have a Campylobacter in your future? [Comment]". Western journal of medicine. 1994 Aug;161(2):186-187 (MEDL:7941546 #19185)    
  456. Neuzil KM; Wang E; Haas DW; Blaser MJ. "Persistence of Campylobacter fetus bacteremia associated with absence of opsonizing antibodies". Journal of clinical microbiology. 1994 Jul;32(7):1718-1720 (MEDL:7929763 #19188)    

    Campylobacter fetus causes systemic infections in immunocompromised hosts. We describe a case in which C. fetus bacteremia apparently relapsed after 7 years in a patient with hypogammaglobulinemia and characterize the serum resistance of the patient's C. fetus strain and the inability of the patient's serum, with and without commercial intravenous immunoglobulin, to opsonize this and another C. fetus strain effectively. The probable presence of a sequestered site of infection in bone, the intrinsic serum resistance of the C. fetus strain, and the absence of specific antibody may account for the persistent infection in this patient. These studies suggest that intravenous immunoglobulin treatment is not useful in eradicating C. fetus bacteremia
  457. Nomura A; Stemmermann GN; Chyou PH; Perez-Perez GI; Blaser MJ. "Helicobacter pylori infection and the risk for duodenal and gastric ulceration". Annals of internal medicine. 1994 Jun 15;120(12):977-981 (MEDL:7741826 #19189)    

    OBJECTIVE: To determine whether a preexisting Helicobacter pylori infection increases the risk for developing duodenal or gastric ulcer. DESIGN: A nested case-control study based on a cohort of 5443 Japanese-American men who had a physical examination and a phlebotomy from 1967 to 1970. SETTING: All 10 general hospitals on the Hawaiian island of Oahu. PATIENTS: 150 patients with gastric ulcer and 65 patients with duodenal ulcer identified in the cohort of study participants after a hospital surveillance period of more than 20 years. MEASUREMENTS: Stored serum specimens from patients and from matched controls were tested for the presence of serum IgG antibody to H. pylori using enzyme-linked immunosorbent assay. RESULTS: 93% of the 150 patients with gastric ulcer and 78% of the matched controls had a positive antibody level for H. pylori-specific IgG, yielding an odds ratio of 3.2 (95% CI, 1.6 to 6.5). For duodenal ulcer, 92% of the 65 patients and 78% of the matched controls had a positive test result, yielding an odds ratio of 4.0 (CI, 1.1 to 14.2). As the level of antibody to H. pylori increased, a statistically significant increase was noted in the risk for gastric and duodenal ulcer. The association with H. pylori infection was statistically significant for both types of ulcer, even when the diagnosis was made 10 or more years after the serum sample had been obtained. CONCLUSION: Preexisting H. pylori infection increases the risk for subsequent development of either duodenal or gastric ulcer disease
  458. Perez-Perez GI; Brown WR; Cover TL; Dunn BE; Cao P; Blaser MJ. "Correlation between serological and mucosal inflammatory responses to Helicobacter pylori". Clinical & diagnostic laboratory immunology. 1994 May;1(3):325-329 (MEDL:7496970 #19193)    

    In 82 patients who underwent gastroduodenoscopy, acute and chronic gastric mucosal inflammation was scored for severity, and systemic humoral immune responses to Helicobacter pylori antigens were assessed by enzyme-linked immunosorbent assays. On the basis of culture, gastric histology, and serologic evaluation, 33 patients were classified as H. pylori infected and 36 were classified as uninfected. Thirteen patients had negative cultures and stains but were seropositive and were analyzed separately from the other two groups. Specific serum immunoglobulin G (IgG) subclass responses to H. pylori whole-cell antigens and specific IgG responses to the 54-kDa heat shock protein homolog (Hp54K) and vacuolating cytotoxin were significantly greater in infected than in uninfected patients as were specific IgA responses to whole-cell antigens and cytotoxin (P < 0.001). Among the H. pylori-infected persons, serum IgG responses to Hp54K and to the vacuolating cytotoxin were correlated with acute mucosal inflammatory scores. In contrast, serum IgA responses to whole-cell sonicate and to vacuolating cytotoxin were inversely related to chronic inflammatory scores. By multivariant regression analysis, only specific serum IgG responses to Hp54K correlated with severity of inflammation (both acute and chronic; P < 0.001); these responses may be markers of inflammation or these antibodies could play a direct role in the pathogenesis of H. pylori-induced inflammation
  459. Perez-Perez GI; Gower CB; Blaser MJ. "Effects of cations on Helicobacter pylori urease activity, release, and stability". Infection & immunity. 1994 Jan;62(1):299-302 (MEDL:8262643 #19199)    

    The urease of Helicobacter pylori is an important antigen and appears critical for colonization and virulence. Several studies have indicated a superficial localization for the H. pylori urease, and the purpose of this study was to determine the effects of cations on the release and stability of urease activity from H. pylori cells. Incubation of partially purified H. pylori urease in water containing 1, 5, or 10 mM Ca2+, Mg2+, K+, Na+, EDTA, or EGTA [ethylene glycol-bis(beta-aminoethyl ether)-N,N,N',N'-tetraacetic acid] had little effect on activity. In contrast, 1 mM Fe3+, Cu2+, Co2+, or Zn2+ substantially (> 80%) inhibited activity, and 10 mM Fe2+, Mn2+, and Ni2+ inhibited about 30% of the activity. Addition of Ca2+ or Mg2+ markedly decreased extraction of urease from intact H. pylori cells by water, but 1 mM Na+, K+, EGTA, or EDTA each had minimal effects on release, suggesting that divalent cations have a role in attachment of urease to H. pylori cells. The stability of enzymatic activity at 4 degrees C was enhanced by addition of glycerol or 2-mercaptoethanol; however, even after loss of activity, full antigenicity for human serum was retained
  460. Shabib S; Laxer R; Silverman E; Perez-Perez G; Blaser M; Sherman P. "Seroprevalence of Helicobacter pylori infection is not increased in pediatric inflammatory arthritides". Journal of rheumatology. 1994 Aug;21(8):1548-1552 (MEDL:7983663 #34635)    

    OBJECTIVE. To determine the seroprevalence of H. pylori infection among children with inflammatory arthritides receiving antiinflammatory drug therapy. METHODS. An enzyme linked immunosorbent assay (ELISA) was used to detect H. pylori specific immunoglobulin G antibody in 95 children with inflammatory arthritides, 53 children with chronic inflammatory bowel diseases and 47 parents of children with inflammatory arthritis. RESULTS. The frequency of seropositivity in children with arthritis (9/95, 9.5%) was not significantly higher than in children with chronic inflammatory bowel diseases (1/53, 1.9%; p = 0.16). Serum samples from parents were positive in 16 of 47 (34%), including 4 parents with children who also demonstrated a positive immune response. CONCLUSION. These data do not provide evidence for an increased frequency of H. pylori infection among children with inflammatory arthritides. The therapeutic use of ulcerogenic medications is likely to be an independent risk factor predisposing to dyspeptic symptoms and gastritis in this patient population
  461. Sharma SA; Miller GG; Perez-Perez GI; Gupta RS; Blaser MJ. "Humoral and cellular immune recognition of Helicobacter pylori proteins are not concordant". Clinical & experimental immunology. 1994 Jul;97(1):126-132 (MEDL:8033409 #19187)    

    Helicobacter pylori is a major cause of chronic antral gastritis and peptic ulcer disease. Further definition is needed of the factors that determine whether infected individuals remain asymptomatic, or ultimately develop ulceration of the mucosa or transformation to malignancy. To explore the possibility that host response to H. pylori may play a role in the outcome of this infection, we have examined humoral and cellular recognition of several H. pylori proteins by seropositive and seronegative persons. A complex mixture of water-extractable cell proteins, which did not include lipopolysaccharide (LPS), was recognized by serum antibodies only in seropositive or infected individuals. IgG from seropositive subjects also bound to urease and to a heat shock protein (hsp)60 that is homologous to the 65-kD mycobacterial heat shock protein, while sera from uninfected individuals were negative. Although antibody responses to these antigens were restricted to seropositive subjects, T cell recognition of the same proteins was found in both seropositive and seronegative subjects. The water extract of H. pylori stimulated peripheral blood mononuclear cells (PBMC) from all subjects, while purified proteins activated lymphocytes of only some seropositive and seronegative subjects. PBMC that were activated by the H. pylori hsp60 did not respond to the autologous human p60 heat shock protein. These results demonstrate that, in contrast to antibody responses, T cell recognition of H. pylori proteins may occur in non-infected persons. In addition, the data suggest that in these subjects, peripheral lymphocytes that are activated by bacterial heat shock proteins do not mediate tissue damage by recognition of human heat shock homologues
  462. Tummuru MK; Cover TL; Blaser MJ. "Mutation of the cytotoxin-associated cagA gene does not affect the vacuolating cytotoxin activity of Helicobacter pylori". Infection & immunity. 1994 Jun;62(6):2609-2613 (MEDL:8188385 #19191)    

    Helicobacter pylori now is recognized as an etiological agent in chronic superficial gastritis and peptic ulcer disease. Although only about 60% of H. pylori isolates produce an immunodominant 128-kDa antigen (CagA; cytotoxin-associated gene product), virtually all H. pylori-infected patients with duodenal ulceration develop a serologic response to the 128-kDa protein, which suggests an association of this gene with ulceration. The cloned cagA gene from H. pylori 84-183 was disrupted by insertion of a kanamycin resistance gene, and this inactivated cagA construct was introduced into H. pylori 84-183 by electrotransformation. Southern hybridization of kanamycin-resistant H. pylori transformants demonstrated that the wild-type cagA gene had been disrupted by insertion of the kanamycin cassette, and immunoblot analysis showed that the mutant strains no longer produced the 128-kDa CagA protein. Similar results were obtained when the cagA mutation was introduced by natural transformation into H. pylori 60190, a high-level toxin-producing strain. The cagA-negative H. pylori strains showed cytotoxin, urease, and phospholipase C activities, C3 binding and adherence similar to those of the isogenic wild-type strains. These findings demonstrate that the cagA gene product does not affect the vacuolating cytotoxin activity of H. pylori
  463. Black, Robert E; Perlman, daniel; Clements, Mary L; Levine, Myron M; Blaser, Martin J. Human volunteer studies in campylobacter jejuni. [S.l.] : Ft. Belvoir Defense Technical Information Center, 1993. 11 p..   

    Campylobacter jejuni and closely related organisms are established enteropathogens, resulting in diarrhea and often dysentery in susceptible children and adults (6). These organisms also cause asymptomatic infections, which are especially frequent in children residing in developing countries, who appear to be exposed frequently from an early age
  464. Blaser MJ. "Helicobacter pylori: microbiology of a 'slow' bacterial infection". Trends in microbiology. 1993 Oct;1(7):255-260 (MEDL:8162405 #19205)    

    The bacterium Helicobacter pylori lives in the gastric mucus layer of humans and induces a chronic inflammatory response that can result in both peptic ulceration and gastric neoplasms. Helicobacter pylori infection can be considered as a 'slow', adaptive and autoregulating process. The mechanisms by which this slow bacterial pathogen survives and interacts with the host immune system may provide a model for other persistent mucosal pathogens
  465. Blaser MJ. "Malaria and the natural history of Helicobacter pylori infection [Letter]". Lancet. 1993 Aug 28;342(8870):551-551 (MEDL:8102682 #19209)       
  466. Blaser MJ. "Role of the S-layer proteins of Campylobacter fetus in serum-resistance and antigenic variation: a model of bacterial pathogenesis". American journal of the medical sciences. 1993 Nov;306(5):325-329 (MEDL:8238090 #19203)       

    Campylobacter fetus are microaerophilic gram-negative bacteria that are pathogens of animals and humans. These organisms possess paracrystalline surface (S-) layers, composed of acidic high molecular weight proteins. C. fetus strains possessing S-layers are resistant to C3b binding, which explains both serum and phagocytosis-resistance. C. fetus strains also can vary the subunit protein size, crystalline structure, and antigenicity of the S-layer it expresses. Therefore, its S-layer permits C. fetus to resist complement and antibodies, two of the key defenses against extracellular pathogens. C. fetus possesses several full-length genes encoding S-layer proteins with both conserved and divergent sequences, which permits gene rearrangement and antigenic variation
  467. Blaser MJ; Kobayashi K; Cover TL; Cao P; Feurer ID; Perez-Perez GI. "Helicobacter pylori infection in Japanese patients with adenocarcinoma of the stomach". International journal of cancer. 1993 Nov 11;55(5):799-802 (MEDL:8244577 #19202)       

    To examine the association of Helicobacter pylori infection with adenocarcinoma of the stomach in Japanese patients, we studied 29 patients and 58 matched controls. Ascertainment of H. pylori status was based on the presence of specific IgG to H. pylori. For the entire group, an association of this infection with gastric adenocarcinoma was suggested but not statistically significant. For patients in a putatively high-risk subgroup (non-cardia tumors and age < or = 70 years), the association was significant. Assays detecting serum IgA to whole H. pylori cells and cytotoxin, IgG to cytotoxin and Hp54K (the heat-shock protein homolog) and serum neutralization of cytotoxin activity each showed clear differences between H. pylori-infected and uninfected persons in this population. However, for none of these assays was there a significant difference between values for H. pylori-infected persons with or without gastric cancer. Thus, while H. pylori infection was associated with non-cardia gastric cancer in Japanese persons < or = 70 years of age, use of these additional serologic markers did not define additional factors that might be associated with increased risk
  468. Blaser MJ; Pei Z. "Pathogenesis of Campylobacter fetus infections: critical role of high-molecular-weight S-layer proteins in virulence". Journal of infectious diseases. 1993 Feb;167(2):372-377 (MEDL:8421171 #19218)       

    Wild-type Campylobacter fetus strains possess high-molecular-weight S-layer proteins (S+) and are highly resistant to serum-mediated killing and phagocytosis. Spontaneous mutant strains lacking these proteins (S-) are serum and phagocytosis sensitive and have reduced virulence in a mouse model. Intact S+ cells were treated with pronase, which made them S- although genotypically S+ and had essentially no effect on other cellular proteins or on viability. Treatment with pronase, but not buffer alone, rendered these cells serum and phagocytosis sensitive and reduced mouse virulence to the level observed for the S- mutant cells. In related studies, purified S-layer proteins diminished neutrophil chemoluminescent responses to a heterologous particulate antigen. Finally, passive administration of antiserum to the 97-kDa S-layer protein partially protected mice against lethal challenge with the S+ strain. These studies define the contribution of the S-layer proteins to C. fetus virulence
  469. Cover TL; Cao P; Lind CD; Tham KT; Blaser MJ. "Correlation between vacuolating cytotoxin production by Helicobacter pylori isolates in vitro and in vivo". Infection & immunity. 1993 Dec;61(12):5008-5012 (MEDL:8225576 #19201)    

    Approximately 50 to 60% of Helicobacter pylori isolates produce a vacuolating cytotoxin in vitro. To assess cytotoxin production in vivo, we sought to determine whether infection with a Tox+ H. pylori strain is associated with the presence of serum antitoxin antibodies. H. pylori isolates and serum samples were obtained from 30 patients, and serum samples were obtained from 20 uninfected patients as controls. Sera were tested by enzyme-linked immunosorbent assay for reactivity with the purified 87-kDa vacuolating cytotoxin, and the 30 H. pylori isolates were tested for vacuolating cytotoxin production. Supernatants from 14 (47%) of the 30 H. pylori isolates induced vacuolation of HeLa cells. Sera from the 30 H. pylori-infected patients reacted with the purified 87-kDa cytotoxin to a greater extent than sera from the uninfected controls for both immunoglobulin G (IgG) and IgA classes (P = 0.0004 and P < 0.0001, respectively). Serum IgG and IgA responses to the purified 87-kDa cytotoxin were higher among the 14 patients infected with Tox+ strains than among the 16 patients infected with Tox- strains (mean optical densities +/- standard errors of the means of 0.603 +/- 0.11 versus 0.234 +/- 0.07 [P = 0.005] and 0.644 +/- 0.12 versus 0.341 +/- 0.08 [P = 0.04] for IgG and IgA, respectively). Infection with a Tox+ strain compared with a Tox- strain was associated with increased antral polymorphonuclear leukocyte inflammation scores (P = 0.04). These data indicate that cytotoxin production by H. pylori isolates in vitro correlates with cytotoxin production in vivo and that infection with Tox+ H. pylori isolates may be associated with increased antral mucosal polymorphonuclear leukocyte infiltration
  470. Cover TL; Reddy LY; Blaser MJ. "Effects of ATPase inhibitors on the response of HeLa cells to Helicobacter pylori vacuolating toxin". Infection & immunity. 1993 Apr;61(4):1427-1431 (MEDL:8454346 #19217)    

    Approximately 50% of Helicobacter pylori strains produce a toxin in vitro that induces vacuolation of eukaryotic cells. To determine whether ion transport pathways are important in the formation of toxin-induced vacuoles, HeLa cells were incubated with H. pylori toxin in the presence of nine different inhibitors of ion-transporting ATPases. Oligomycin, an inhibitor of predominantly F1F0-type ATPases, had no effect on toxin activity. Inhibitors of predominantly V-type ATPases, exemplified by bafilomycin A1, inhibited the formation of vacuoles in response to the H. pylori toxin and reversed the vacuolation induced by the toxin. In contrast, at concentrations of > or = 100 nM, ouabain and digoxin, inhibitors of the Na(+)-K+ ATPase, potentiated the activity of H. pylori toxin. The inhibitory effects of bafilomycin A1 could not be overcome by the potentiating effects of ouabain. These data suggest that intact activity of the vacuolar ATPase of eukaryotic cells is a critical requirement in the pathogenesis of cell vacuolation induced by H. pylori toxin and that vacuole formation by this toxin is associated with altered cation transport within eukaryotic cells
  471. Kervella M; Pages JM; Pei Z; Grollier G; Blaser MJ; Fauchere JL. "Isolation and characterization of two Campylobacter glycine-extracted proteins that bind to HeLa cell membranes". Infection & immunity. 1993 Aug;61(8):3440-3448 (MEDL:8335374 #19212)    

    Two immunogenic proteins of 27 (CBF1) and 29 (CBF2) kDa from enteropathogenic Campylobacter species appear to bind to mammalian cells. We purified these two proteins from a pathogenic and adherent Campylobacter jejuni strain to homogeneity by using acid extraction, preparative gel electrophoresis, and electroelution. Polyclonal rabbit antisera to these proteins were prepared. Immunologic studies indicate that CBF1 corresponds to the PEB1 and CBF2 corresponds to the PEB4 described by Pei et al. (Z. Pei, R. T. Ellison, and M. Blaser, J. Biol. Chem. 226:16363-16369, 1991). Immunogold labeling of a C. jejuni adherent strain with anti-CBF1, anti-CBF2, and anti-PEB1 suggested that CBF1 (PEB1) is surface exposed while CBF2 (PEB4) is not. Analysis of whole-cell extracts from 14 strains by sodium dodecyl sulfate (SDS)-polyacrylamide gel electrophoresis with 7 M urea and immunoblotting with antisera to CBF1 and CBF2 suggests that CBF proteins from adherent and nonadherent strains are different. Use of purified proteins in a microassay of adherence to cellular membranes indicated that CBF1 was much more adherent than CBF2. Adherence of C. jejuni to viable HeLa cells was markedly reduced with the antiserum to CBF1, whereas the CBF2 antiserum was a poor inhibitor. Purified CBF1 competitively inhibited adherence of whole bacteria to HeLa cells, whereas purified CBF2 was no better a competitor than bovine serum albumin. Adherence of CBF2 was markedly reduced in the presence of Tween 20 or SDS, whereas adherence of CBF1 was reduced only by SDS. We conclude that (i) CBF1 (PEB1) is surface exposed and may be the key protein for C. jejuni adhesion and (ii) CBF2 (PEB4) may be complexed with CBF1 and may passively coadhere with CBF1 under certain experimental conditions. Adherent and nonadherent strains contain different isotypes of these two proteins which could be useful markers of C. jejuni adhesion
  472. Kervella, Michele; Pages, Jean-Marie; Pei, Zhiheng; Grollier, Chislaine; Blaser, Martin J. Isolation and Characterization of Two Campylobacter Glycine-Extracted Proteins That Bind to HeLa Cell Membranes. [S.l.] : Ft. Belvoir Defense Technical Information Center, 1993. 11 p..   

    wo immunogenic proteins of 27 (CBF1) and 29 (CBF2) kDa from enteropathogenic Campylobacter species appear to bind to mammalian cells. We purified these two proteins from a pathogenic and adherent Campylobacter jejuni strain to homogeneity using acid extraction, preparative gel electrophoresis and electroelution. Polyclonal rabbit antisera to these proteins were prepared. Immunologic studies indicate that CBF1 corresponds to the PEB1 and CBF2 corresponds to the PEB4 described by Pei et al
  473. Mishu B; Blaser MJ. "Role of infection due to Campylobacter jejuni in the initiation of Guillain-Barre syndrome". Clinical infectious diseases. 1993 Jul;17(1):104-108 (MEDL:8353228 #19214)       

    Recent reports suggest that infection with Campylobacter jejuni, a common enteric pathogen, may cause Guillain-Barre syndrome (GBS) by triggering demyelination of peripheral nerves. GBS is preceded by an acute infectious illness (due to a variety of agents) in 50%-75% of cases; the onset of neurological symptoms is preceded by diarrhea in 10%-30% of cases. In the last decade, more than 20 published anecdotal reports and case series have described patients with C. jejuni infection documented 1-3 weeks before onset of GBS. Cultures of fecal samples obtained at the onset of neurological symptoms from patients with GBS have yielded C. jejuni in more than 25% of cases. A relatively rare serotype, Penner type O19, is overrepresented among isolates of C. jejuni from Japanese patients with GBS. Serological studies suggest that 20%-40% of patients with GBS have evidence of recent C. jejuni infection. In summary, infection with C. jejuni is a common antecedent to GBS and probably plays a role in initiating demyelination; although several pathogenic mechanisms are possible, none has been proven
  474. Mishu B; Ilyas AA; Koski CL; Vriesendorp F; Cook SD; Mithen FA; Blaser MJ. "Serologic evidence of previous Campylobacter jejuni infection in patients with the Guillain-Barre syndrome". Annals of internal medicine. 1993 Jun 15;118(12):947-953 (MEDL:8489109 #19215)    

    OBJECTIVE: To determine if patients with the Guillain-Barre syndrome are likely to have had Campylobacter jejuni infection before onset of neurologic symptoms. DESIGN: A case-control study. SETTING: Several university medical centers. PATIENTS: Case patients met clinical criteria for the Guillain-Barre syndrome between 1983 and 1990 and had a serum sample collected and frozen within 3 weeks after onset of neurologic symptoms (n = 118). Disease controls were patients with other neurologic illnesses (n = 56); healthy controls were hospital employees or healthy family members of patients (n = 47). MEASUREMENTS: Serum IgA, IgG, and IgM antibodies to C. jejuni were determined by enzyme-linked immunosorbent assays. Assays were done in a blinded manner. RESULTS: Optical density ratios > or = 2 in two or more immunoglobulin classes were seen in 43 (36%) of patients with the Guillain-Barre syndrome and in 10 (10%) of controls (odds ratio, 5.3; 95% CI, 2.4 to 12.5; P < 0.001). Increasing the optical density ratio or the number of immunoglobulin classes necessary to yield a positive result increased the strength of the association. The number of patients with the Guillain-Barre syndrome who had positive serologic responses was greatest from September to November (P = 0.02). Male patients were three times more likely to have serologic evidence of C. jejuni infection (P = 0.009); the proportion of patients with the syndrome who had a positive serologic response increased with age. CONCLUSIONS: Patients with the Guillain-Barre syndrome are more likely than controls to have serologic evidence of C. jejuni infection in the weeks before onset of neurologic symptoms. Campylobacter jejuni may play a role in the initiation of the Guillain-Barre syndrome in many patients
  475. Mishu, Ban; Blaser, Martin J. Role of infection due to campylobacter jejuni in the initiation of Guillain-Barre syndrome. [S.l.] : Ft. Belvoir Defense Technical Information Center, 1993. 7 p..   

    Recent reports suggest that infection with Campylobacter jejuni, a common enteric pathogen, may cause Guillain-Barre syndrome (GBS) by triggering demyelination of peripheral nerves. GBS is preceded by an acute infectious illness (due to a variety of agents) in 50%-75% of cases the onset of neurological symptoms is preceded bt diarrhea in 10%-30% of cases. In the last decade, more than 20 published anecdotal reports and case series have described patients with C. jejuni infectious documented 1-3 weeks before onset of GBS. Cultures of fecal samples obtained at the onset of neurological symptoms from patients with GBS have yielded C. jejuni in more than 25% of cases. A relatively rare serotype, Penner type 019, is over represented among isolates of C. jejuni from Japanese patients with GBS. Serological studies suggest that 20%-40% of patients with GBS have evidence of recent C. jejuni infection. In summary, infection with C. jejuni is a common antecedent to GBS and probably plays a role initiating demyelination; although several pathogenic mechanisms are possible, none has been proven
  476. Pei Z; Blaser MJ. "PEB1, the major cell-binding factor of Campylobacter jejuni, is a homolog of the binding component in gram-negative nutrient transport systems". Journal of biological chemistry. 1993 Sep 5;268(25):18717-18725 (MEDL:8360165 #19206)    

    The protein PEB1 (28 kDa) is a common antigen and a major cell adherence molecule of Campylobacter jejuni and Campylobacter coli. We created a bank of chromosomal DNA fragments of C. jejuni strain 81-176 using lambda gt11. Screening this bank in Escherichia coli Y1090 cells with antibody raised against purified PEB1 enabled us to isolate and to purify a clone with a 2.6-kilobase insert expressing an immunoreactive protein of 28 kDa. DNA sequencing revealed that the insert contains three complete and two partial open reading frames (ORFs), designated 5' to 3' as ORFs A-E. The peb1A gene (ORF D) contains 780 bases encoding a 259-residue polypeptide having a calculated molecular mass of 28,181 Da. The peptide sequence starting at residue 27 matches that determined from aminoterminal sequencing of mature PEB1 from C. jejuni. The first 26 residues contain typical signal peptidase I and II cleavage sites. The deduced amino acid composition and pI of the recombinant mature protein are similar to those determined for purified PEB1. Gene bank searches indicated significant overall homology of peb1A and ORF C with operons for amino acid transport systems in other Gram-negative organisms. peb1A is homologous to the binding components of systems such as glnH (27.8%) and hisJ (28.9%), whereas ORF C has nearly 50% identity to glnQ and hisP. Thus, PEB1 could be involved both in binding to intestinal cells and in amino acid transport
  477. Pei, Shiheng; Blaser, Martin J. PEB1, the major cell-binding factor of campylobacter jejuni, is a homolog of the binding component in gram-negative nutrient transport system. [S.l.] : Ft. Belvoir Defense Technical Information center, 1993. 12 p..   

    The protein PEB1 (28 kDa) is a common antigen and a major cell adherence molecule of Campylobacter jejuni and Campylobacter coli. We created a bank of chromosomal DNA fragments of C. jejuni strain 81-176 using Lambda 11. Screening this bank in Escherichia coli Y1090 cells with antibody raised against purified PEB1 enabled us to isolate and to purify a clone with a 2.6-kilobase insert expressing an immunoreactive protein of 28 kDa. DNA sequencing revealed that the insert contains three complete and two partial open reading frames (ORFs) designated 5' to 3' as ORFs A-E. The peb1A gene (ORF D) contains 780 bases encoding a 259-residue polypeptide having a calculated molecular mass of 28,181 Da. The peptide sequence starting at residue 27 matches that determined from amino-terminal sequencing of mature PEB1 from C. jejuni
  478. Peterson WL; Graham DY; Marshall B; Blaser MJ; Genta RM; Klein PD; Stratton CW; Drnec J; Prokocimer P; Siepman N. "Clarithromycin as monotherapy for eradication of Helicobacter pylori: a randomized, double-blind trial". American journal of gastroenterology. 1993 Nov;88(11):1860-1864 (MEDL:8237933 #19204)    

    Current regimens to eradicate Helicobacter pylori usually consist of metronidazole plus a bismuth compound, as well as a third agent such as tetracycline. Such regimens are not ideal because organisms may be metronidazole-resistant, side-effects occur, and compliance is often poor. This randomized, double-blind study was designed to assess the ability of clarithromycin, a new macrolide antimicrobial, as monotherapy to eradicate H. pylori. Thirty-seven healthy volunteers who were H. pylori positive by 13C-urea breath test plus histology and/or culture completed 14 days of oral therapy with clarithromycin in one of three dosages. Eradication, defined as all three tests negative at 4-6 wk after the end of therapy, was achieved in 2/13 (15%) with clarithromycin 500 mg bid, 4/11 (36%) with 1000 mg bid, and 7/13 (54%) with 500 mg qid. Isolates of H. pylori were resistant to clarithromycin prior to therapy in 12% of subjects, and became resistant during therapy in 21% of subjects. Taste perversion, the most common side effect, resulted in one subject terminating therapy. Conclusions: Whereas clarithromycin is a promising antimicrobial in the eradication of H. pylori, it is not sufficient to be used as monotherapy
  479. Taylor DN; Perlman DM; Echeverria PD; Lexomboon U; Blaser MJ. "Campylobacter immunity and quantitative excretion rates in Thai children". Journal of infectious diseases. 1993 Sep;168(3):754-758 (MEDL:8354916 #19207)       

    Campylobacter species were isolated from 61 (15%) of 416 Thai children < 5 years old with diarrhea. Although the baseline levels of Campylobacter-specific antibody increased with age, 80.3% of Campylobacter-infected children seroconverted compared with 12.9% of 45 Shigella-infected patients used as controls. The response to acute infection was greatest in the 6- to 12-month-old group. Nonseroconverters had higher initial IgG levels than did seroconverters (P = .001). Quantitative cultures showed a range of 1-8 log10 Campylobacter cfu/g of stool (median, 6.0 log10), and the seroconversion rate was highest in those with the highest Campylobacter excretion. Fecal Campylobacter excretion was inversely related to age (chi 2 for trend, P = .03). These studies indicate that endemic Campylobacter exposure frequently induces seroconversion in young children, whether Campylobacter is isolated as a single pathogen or one of multiple pathogens, and that fecal excretion of the organism is inversely related to the age-related immune response to infection
  480. Taylor, David N; Perlman, Daniel M; Echeverria, Peter; Lexomboon, Udom; Blaser, Martin J. Campylobacter immunity and quantitative excretion rates in Thai children. [S.l.] : Ft. Belvoir Defense Technical Information Center, 1993. 7 p..   

    Campylobacter species were isolated from 61 (15%) of 416 Thai children >5 years old with diarrhea. Although the baseline levels of Campylobacter-specific antibody increased with age, 80.3% of Campylobacter- infected children seroconverted compared with 12.9% of 45 Shigella-infected patients used as controls. The response to acute infection was greatest in the 6- to 12-month-old group. Nonseroconverters had higher initial IgG levels than did seroconverters(P=.001). Quantitative cultures showed a range of 1-8 log sub 10 Campylobacter cfu/g of stool (median, 6.0 log sub 10), and the seroconversion rate was highest in those with the highest Campylobacter excretion. Fecal Campylobacter excretion was inversely related to age (x(2) for trend, P=.03). These studies indicate that endemic Campylobacter exposure frequently induces seroconversion in young children, whether Campylobacter is isolated as a single pathogen or one of multiple pathogens, and that fecal excretion of the organism is inversely related to the age-related immune response to infection
  481. Taylor, David N; Perlman, Daniel M; Echeverria, Peter; Lexomboon, Udom; Blaser, Martin J. Campylobacter immunity and quantitative excretion rates in Thai children. [S.l.] : Ft. Belvoir Defense Technical Information Center, 1993. 7 p..   

    Campylobacter species were isolated from 61 (15%) of 416 Thai children >5 years old with diarrhea. Although the baseline levels of Campylobacter-specific antibody increased with age, 80.3% of Campylobacter- infected children seroconverted compared with 12.9% of 45 Shigella-infected patients used as controls. The response to acute infection was greatest in the 6- to 12-month-old group. Nonseroconverters had higher initial IgG levels than did seroconverters(P=.001). Quantitative cultures showed a range of 1-8 log sub 10 Campylobacter cfu/g of stool (median, 6.0 log sub 10), and the seroconversion rate was highest in those with the highest Campylobacter excretion. Fecal Campylobacter excretion was inversely related to age (x(2) for trend, P=.03). These studies indicate that endemic Campylobacter exposure frequently induces seroconversion in young children, whether Campylobacter is isolated as a single pathogen or one of multiple pathogens, and that fecal excretion of the organism is inversely related to the age-related immune response to infection
  482. Tummuru MK; Blaser MJ. "Rearrangement of sapA homologs with conserved and variable regions in Campylobacter fetus". Proceedings of the National Academy of Sciences of the United States of America. 1993 Aug 1;90(15):7265-7269 (MEDL:8346244 #19210)       

    The Campylobacter fetus surface-layer (S-layer) proteins mediate both complement resistance and antigenic variation in mammalian hosts. Wild-type strain 23D possesses the sapA gene, which encodes a 97-kDa S-layer protein, and several sapA homologs are present in both wild-type and mutant strains. Here we report that a cloned silent gene (sapA1) in C. fetus can express a functional full-length S-layer protein in Escherichia coli. Analysis of sapA and sapA1 and partial analysis of sapA2 indicate that a block of approximately 600 bp beginning upstream and continuing into the open reading frames is completely conserved, and then the sequences diverge completely, but immediately downstream of each gene is another conserved 50-bp sequence. Conservation of sapA1 among strains, the presence of a putative Chi (RecBCD recognition) site upstream of sapA, sapA1, and sapA2, and the sequence identities of the sapA genes suggest a system for homologous recombination. Comparison of the wild-type strain (23D) with a phenotypic variant (23D-11) indicates that variation is associated with removal of the divergent region of sapA from the expression locus and exchange with a corresponding region from a sapA homolog. We propose that site-specific reciprocal recombination between sapA homologs leads to expression of divergent S-layer proteins as one of the mechanisms that C. fetus uses for antigenic variation
  483. Tummuru MK; Cover TL; Blaser MJ. "Cloning and expression of a high-molecular-mass major antigen of Helicobacter pylori: evidence of linkage to cytotoxin production". Infection & immunity. 1993 May;61(5):1799-1809 (MEDL:8478069 #19216)    

    A high-molecular-mass (120- to 128-kDa) Helicobacter pylori antigen has been associated with peptic ulcer disease. We created a bank of 40,000 random chromosomal fragments of H. pylori 84-183 by using lambda ZapII. Screening of this bank in Escherichia coli XL1-Blue with absorbed serum from an H. pylori-infected person permitted the isolation and purification of a clone with a 3.5-kb insert. Subcloning of this insert (pMC3) permitted the expression of a recombinant H. pylori protein that had a mass of approximately 96 kDa and that was recognized by the human serum. Sera that were obtained from H. pylori-infected persons and that recognized the native 120- to 128-kDa H. pylori antigen recognized the recombinant 96-kDa pMC3 protein to a significantly greater extent than did sera that did not recognize the native H. pylori antigen. All 19 H. pylori isolates producing the 120- to 128-kDa antigen hybridized with pMC3; none of 13 nonproducers did so (P < 0.001). Because all 15 isolates producing the vacuolating cytotoxin hybridized with pMC3, we called the gene cagA (cytotoxin-associated gene). Sequence analysis of pMC3 identified an open reading frame of 859 amino acids, without a termination codon. Parallel screening of a lambda gt11 library with human serum revealed positive plaques with identical 0.6-kb inserts and sequences matching the sequence of the downstream region of pMC3. To clone the full-length gene, we used the 0.6-kb fragment as a probe and isolated a clone with a 2.7-kb insert from the lambda ZapII genomic library. Nucleotide sequencing of this insert (pYB 2) revealed a 785-bp sequence that overlapped the downstream region of pMC3. Translation of the complete nucleotide sequence of cagA revealed an open reading frame of 1,181 amino acids yielding a protein of 131,517 daltons. There was no significant homology with any previously reported protein sequence. These findings indicate the cloning and characterization of a high-molecular-mass H. pylori antigen potentially associated with virulence and with cytotoxin production
  484. Vriesendorp FJ; Mishu B; Blaser MJ; Koski CL. "Serum antibodies to GM1, GD1b, peripheral nerve myelin, and Campylobacter jejuni in patients with Guillain-Barre syndrome and controls: correlation and prognosis". Annals of neurology. 1993 Aug;34(2):130-135 (MEDL:8338337 #19211)       

    Serum antibodies to monosialoganglioside (GM1), disialoganglioside (GD1b), and Campylobacter jejuni, measured by enzyme-linked immunosorbent assay and serum antibodies to peripheral nerve myelin, measured by the C1 fixation and transfer assay, were studied in 58 acute-phase patients with Guillain-Barre syndrome (GBS), 42 disease controls, and 29 normal controls. Anti-peripheral nerve myelin antibodies were elevated in 57 of 58 patients with GBS compared with controls, whereas only 8.6% had increased antibody titers to GM1 and 10.3% to GD1b. Only low antibody titers (GM1) or no antibodies (GD1b) were found in controls. More GBS patients (17.2%) than controls (7%) had antibodies to C jejuni. Poor recovery with inability to walk at 1 year after onset of symptoms was seen in 3 (5%) of the patients with GBS. All 3 patients had serological evidence of recent C jejuni infection but no antibodies to GM1 or GD1b. GBS patients with antibodies to GM1 or GD1b had excellent recovery. Our data indicate that antibodies to GM1 or GD1b do not necessarily mediate the extensive axonal damage seen in these severely affected patients
  485. Wang E; Garcia MM; Blake MS; Pei Z; Blaser MJ. "Shift in S-layer protein expression responsible for antigenic variation in Campylobacter fetus". Journal of bacteriology. 1993 Aug;175(16):4979-4984 (MEDL:7688715 #19213)    

    Campylobacter fetus strains possess regular paracrystalline surface layers (S-layers) composed of high-molecular-weight proteins and can change the size and crystalline structure of the predominant protein expressed. Polyclonal antisera demonstrate antigenic cross-reactivity among these proteins but suggest differences in epitopes. Monoclonal antibodies to the 97-kDa S-layer protein of Campylobacter fetus subsp. fetus strain 82-40LP showed three different reactivities. Monoclonal antibody 1D1 recognized 97-kDa S-layer proteins from all C. fetus strains studied; reactivity of monoclonal antibody 6E4 was similar except for epitopes in S-layer proteins from reptile strains and strains with type B lipopolysaccharide. Monoclonal antibody 2E11 only recognized epitopes on S-layer proteins from strains with type A lipopolysaccharide regardless of size. In vitro shift from a 97-kDa S-layer protein to a 127-kDa S-layer protein resulted in different reactivity, indicating that size change was accompanied by antigenic variation. To examine in vivo variation, heifers were genetically challenged with Campylobacter fetus subsp. venerealis strains and the S-layer proteins from sequential isolates were characterized. Analysis with monoclonal antibodies showed that antigenic reactivities of the S-layer proteins were varied, indicating that these proteins represent a system for antigenic variation
  486. Weitkamp JH; Perez-Perez GI; Bode G; Malfertheiner P; Blaser MJ. "Identification and characterization of Helicobacter pylori phospholipase C activity". Zentralblatt fur bakteriologie. 1993 Sep;280(1-2):11-27 (MEDL:8280931 #19208)    

    We analyzed 11 H. pylori isolates from humans using the artificial chromogenic substrate paranitrophenylphosphorylcholine to detect phospholipase C (PLC) activity. The range of PLC in sonicates was 8.8-92.3 (Mean 56.9 +/- 6.5) nmol of substrate hydrolysed min-1 mg-1 protein; the amount of activity was not associated with urease or cytotoxin levels. Addition of sorbitol or glycerol enhanced PLC activity of H. pylori sonicate and purified PLC from C. perfringens (PLC1) but not purified PLC from B. cereus (PLC3). H. pylori sonicates had little acid phosphatase and no detectable alkaline phosphatase activity, and H. pylori PLC showed markedly different biochemical characteristics from either phosphatase. In total, these studies indicate that activity measured in H. pylori sonicate by PLC assay is due to PLC and not phosphatase activity. The temperature optimum for PLC activity of H. pylori sonicate was 56 degrees C and for PLC 1 was 65 degrees C. For H. pylori PLC and PLC1, optimal activity occurred at pH 8. Despite multiple similarities between H. pylori PLC and PLC1, known PLC inhibitors show different interactions with each enzyme. Although PLC activity is present in many subcellular constituents of H. pylori, including culture supernatants and water extracts, highest specific activity is associated with a membrane-enriched fraction
  487. Blaser MJ. "Helicobacter pylori: its role in disease". Clinical infectious diseases. 1992 Sep;15(3):386-391 (MEDL:1520782 #19223)       
  488. Blaser MJ. "Hypotheses on the pathogenesis and natural history of Helicobacter pylori-induced inflammation". Gastroenterology. 1992 Feb;102(2):720-727 (MEDL:1732141 #19231)    

    Although Helicobacter pylori is now recognized as playing an etiologic role in chronic gastritis and peptic ulcer disease, information on the pathogenesis and natural history of infection is limited. A model is proposed in which luminal H. pylori secrete substances that mediate inflammation that is beneficial to the organism but ultimately deleterious for the host; in addition to tissue damage, inflammation also affects gastric secretory function. In this model, the host may attempt to suppress the inflammatory response, and the adequacy of this postulated down-regulation determines pathological and clinical outcome. The effects of the inflammatory process on gastrin-hydrochloric acid homeostasis may be of critical importance in the pathogenesis of peptic ulcer disease. Because the long-term consequences of H. pylori colonization reflect the continued presence of the organism in the host over years or decades, it may be useful to consider this as a 'slow' bacterial infection
  489. Blaser MJ; Miotto K; Hopkins JA. "Molecular probe analysis of Shigella dysenteriae type 1 isolates from 1940 to 1987". International journal of epidemiology. 1992 Jun;21(3):594-598 (MEDL:1353066 #19226)       

    Fourteen strains of Shigella dysenteriae type 1 (Shiga bacillus) isolated from people in diverse locations from 1940 to 1987 were studied. Southern hybridization with three cloned Escherichia coli genes, Shiga-like toxin I (SLTI), frd, and ompF, was used to determine restriction fragment length polymorphism (RFLP) of the genomic DNA of these strains. Digestion with each of four restriction endonucleases generated fragments of identical size to which the frd and ompF hybridized for each of the 14 strains, indicating the conservation of these genes and their flanking sequences. In contrast, after digestion with HindIII, EcoRV, and ClaI and probing with SLTI, there were RFLP among the strains. The results showed three clones of the Shiga bacillus, and suggested that dissemination of a single clone may continue for decades within a wide geographical area
  490. Blaser, Martin J; Perez-Perez, Guillermo I. Humoral immune response to Lipopolysaccaride antigens of Campylobacter jejuni. [Alexandria, VA] : Ft. Belvoir Defense Technical Information Center, 1992. 7 p..   

    Campylobacter jejuni and the closely related organism Campylobacter coli have been established as among the most common bacterial causes of acute diarrheal disease of humans in developed and developing countries (5.8). A wide variety of mammalian and avian species also are infected by those organisms and thus represent an important reservoir for transmission to humans. Development of vaccines against these organisms would therefore be worthwhile, but knowledge of their antigens is rudimentary
  491. Cover TL; Blaser MJ. "Helicobacter pylori and gastroduodenal disease". Annual review of medicine. 1992;43(1):135-145 (MEDL:1580578 #19234)       

    Helicobacter pylori infection is now recognized as the primary cause of active chronic gastritis in humans. Most infected persons remain asymptomatic, but are at increased risk for the development of peptic ulcer disease and possibly gastric cancer. The pathogenesis of this infection is not well understood, but motility and urease activity are virulence factors in an animal model. The eradication of H. pylori infection is associated with resolution of gastritis and a decreased rate of duodenal ulcer recurrence
  492. Cover TL; Blaser MJ. "Purification and characterization of the vacuolating toxin from Helicobacter pylori". Journal of biological chemistry. 1992 May 25;267(15):10570-10575 (MEDL:1587837 #19227)    

    A vacuolating toxin was purified to homogeneity from broth culture supernatant of the human gastric bacterium, Helicobacter pylori. The procedure for isolating the toxin included ammonium sulfate precipitation, hydrophobic interactive chromatography, size exclusion chromatography, and anion exchange chromatography, which together resulted in a greater than 5000-fold purification of toxin activity. The molecular mass of the purified, denatured toxin was 87,000 +/- 320 daltons, and the native toxin was an aggregate with a molecular mass greater than or equal to 972,000 daltons. The amino-terminal sequence of the purified toxin was partially homologous with internal sequences of numerous transport or ion channel proteins. Antiserum raised against the M(r) = 87,000 protein neutralized toxin activity, whereas preimmune serum did not. When reacted with specific antiserum to the M(r) = 87,000 protein in an enzyme-linked immunosorbent (ELISA) assay, culture supernatants from eight tox+ H. pylori strains produced significantly higher optical density readings than eight tox- supernatants (0.614 +/- 0.11 versus 0.046 +/- 0.01, p less than 0.0001). Sera from H. pylori-infected humans recognized the purified M(r) = 87,000 protein significantly better by ELISA than sera from uninfected persons (0.424 +/- 0.06 versus 0.182 +/- 0.02, p = 0.0009). Finally, ELISA recognition of the purified M(r) = 87,000 protein by human sera was significantly associated with toxin-neutralizing activity (p = 0.019, r = 0.518)
  493. Cover TL; Cao P; Murthy UK; Sipple MS; Blaser MJ. "Serum neutralizing antibody response to the vacuolating cytotoxin of Helicobacter pylori". Journal of clinical investigation. 1992 Sep;90(3):913-918 (MEDL:1522241 #19221)       

    Approximately 50% of Helicobacter pylori isolates produce a cytotoxin in vitro that induces vacuolation of eukaryotic cells. To determine the in vivo relevance of this phenomenon, we sought to detect cytotoxin-neutralizing antibodies in sera from H. pylori-infected persons. As a group, sera from 29 H. pylori-infected patients neutralized the activity of the purified cytotoxin to a significantly greater extent than sera from 24 uninfected persons (P = 0.007). The cytotoxin neutralizing activity in sera from H. pylori-infected persons was mediated predominantly by the purified IgG fraction. Sera from H. pylori-infected persons neutralized the cytotoxins produced by multiple H. pylori strains, but failed to neutralize trimethylamine-induced cell vacuolation. Neutralization of cytotoxin activity by human or immune rabbit sera was associated with immunoblot IgG recognition of an 87-kD H. pylori protein. Similarly, neutralization of the toxin by sera was associated with IgG recognition of the purified cytotoxin in an enzyme-linked immunosorbent assay (P less than 0.0001). The presence of cytotoxin-neutralizing antibodies in sera from H. pylori-infected persons indicates that the cytotoxin is synthesized in vivo
  494. Cover TL; Halter SA; Blaser MJ. "Characterization of HeLa cell vacuoles induced by Helicobacter pylori broth culture supernatant". Human pathology. 1992 Sep;23(9):1004-1010 (MEDL:1381332 #19225)       

    Helicobacter pylori broth culture supernatants induce eukaryotic cell vacuolation in vitro, a phenomenon that has been attributed to cytotoxic activity. We sought to characterize further the vacuolation of HeLa cells that occurs in response to H pylori culture supernatant. Nascent vacuoles were detectable by electron microscopy after 90 minutes of incubation with H pylori supernatant and were not associated with any identifiable organelle. After 6 days of incubation with H pylori supernatant, vacuoles were membrane-bound structures filled with electron-dense debris, which resembled secondary lysosomes. Acid phosphatase activity was detected within the vacuoles. The vacuoles induced by H pylori supernatant were then compared with vacuoles induced by trimethylamine, a weak base known to induce lysosomal swelling. Neutral red dye rapidly entered the vacuoles induced by either H pylori supernatant or trimethylamine, and both types of vacuoles were reversible. Compared with trimethylamine-induced vacuoles, the vacuoles induced by H pylori supernatant were larger and typically lacked a limiting membrane. In the early stages of formation, vacuoles induced by trimethylamine were labeled by lucifer yellow, a pinocytotic marker, whereas H pylori cytotoxin-induced vacuoles were not. These data suggest that trimethylamine-induced vacuoles arise directly from endocytic compartments, whereas H pylori cytotoxin induces vacuole formation via an autophagic mechanism
  495. Cover TL; Vaughn SG; Cao P; Blaser MJ. "Potentiation of Helicobacter pylori vacuolating toxin activity by nicotine and other weak bases". Journal of infectious diseases. 1992 Nov;166(5):1073-1078 (MEDL:1402018 #19219)       

    About 50% of Helicobacter pylori isolates produce a vacuolating toxin in vitro, which may be an important determinant of virulence. Because ammonium salts potentiate H. pylori toxin activity, the effect of other weak bases upon toxin activity was determined. Vacuolation of HeLa cells was quantitated using a neutral red uptake assay. As expected, ammonium chloride, trimethylamine, triethanolamine, and nicotine each induced vacuolation of HeLa cells when tested independently. In addition, each of these weak bases potentiated H. pylori vacuolating toxin activity, whereas sodium chloride or sodium hydroxide did not. Sequential incubation of cells with toxin followed by nicotine resulted in potentiation of vacuolation, whereas sequential incubation in the reverse order did not lead to potentiation. Monensin inhibited the formation of vacuoles by either H. pylori vacuolating toxin or nicotine. The potentiation of H. pylori toxin activity by ammonia and nicotine may contribute to gastroduodenal mucosal injury associated with this infection
  496. Dunn BE; Roop RM; Sung CC; Sharma SA; Perez-Perez GI; Blaser MJ. "Identification and purification of a cpn60 heat shock protein homolog from Helicobacter pylori". Infection & immunity. 1992 May;60(5):1946-1951 (MEDL:1563786 #19228)    

    Helicobacter pylori is associated with gastritis and peptic ulcer disease in humans. We have identified a homolog of the chaperonin cpn60 family of heat shock proteins in H. pylori, referred to as Hp54K. Hp54K, purified from water-extractable H. pylori proteins, migrated as a single band at 54 kDa by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Its native molecular mass was 740 kDa; thus, Hp54K apparently comprises a 14-mer. The N-terminal 33 residues of Hp54K exhibited 60.6, 57.6, 54.5, 54.5, 51.5, and 51.5% identity with corresponding sequences in the following cpn60 homologs: HtpB (Legionella pneumophila), P1 (human mitochondria), GroEL (Escherichia coli), BA60K (Brucella abortus), HypB (Chlamydia trachomatis), and the 65-kDa immunodominant protein of Mycobacterium bovis BCG, respectively. Hp54K was the only protein recognized in whole-cell preparations of H. pylori by immunoblotting using monospecific antisera against cpn60 homologs from L. pneumophila, E. coli, C. trachomatis, and M. bovis BCG. Antiserum against Hp54K recognized proteins with molecular masses of 50 to 60 kDa in a large number of gram-negative bacteria, consistent with the known highly conserved nature of cpn60 proteins. Hp54K is a major protein and is immunogenic in humans infected with H. pylori. Thus, Hp54K shares many similarities with known cpn60 homologs. On the basis of the proposed role of other cpn60 proteins in induction of chronic inflammation, immune cross-reactivity between Hp54K and gastric tissue may provide an important link between H. pylori infection and gastritis
  497. Gubbins GP; Schubert TT; Attanasio F; Lubetsky M; Perez-Perez GI; Blaser MJ. "Helicobacter pylori seroprevalence in patients with rheumatoid arthritis: effect of nonsteroidal anti-inflammatory drugs and gold compounds". American journal of medicine. 1992 Oct;93(4):412-418 (MEDL:1357968 #19220)       

    PURPOSE: To investigate the relationship between Helicobacter pylori infection and nonsteroidal anti-inflammatory drug (NSAID) intolerance and the effect of gold use on the seroprevalence of H. pylori. PATIENTS AND METHODS: We examined the frequency of discontinuation of NSAIDs in 132 unselected patients with rheumatoid arthritis attending an outpatient subspecialty clinic, and the effect of gold compound use on the seroprevalence (by IgG enzyme-linked immunosorbent assay) of H. pylori infection in this population. Logistic and multivariate regression analysis was performed adjusting for age, gender, ethnic origin, history of ulcer, and duration of rheumatoid arthritis. RESULTS: Fifty-four patients had a positive serology for H. pylori (41%). Twenty-seven of the seropositive patients (50%), versus 45 of the seronegative patients (57.7%), had to discontinue NSAIDs (aspirin and/or nonaspirin) at least once since their diagnosis of rheumatoid arthritis because of gastrointestinal side effects (odds ratio [OR], 0.93; 95% confidence interval [CI], 0.63 to 1.38). Forty-one of the seropositive patients (76%) had received gold compounds as compared with 62 of the seronegative patients (79.5%) (OR: 0.96; 95% CI: 0.61 to 1.50). CONCLUSION: We did not find any relationship between H. pylori seropositivity and NSAID intolerance in patients with rheumatoid arthritis. In addition, our results do not demonstrate a reduction in H. pylori seroprevalence in rheumatoid arthritis patients treated with gold compounds
  498. Mai UE; Perez-Perez GI; Allen JB; Wahl SM; Blaser MJ; Smith PD. "Surface proteins from Helicobacter pylori exhibit chemotactic activity for human leukocytes and are present in gastric mucosa". Journal of experimental medicine. 1992 Feb 1;175(2):517-525 (MEDL:1732414 #19230)       

    The mechanism by which Helicobacter pylori, a noninvasive bacterium, initiates chronic antral gastritis in humans is unknown. We now show that H. pylori releases products with chemotactic activity for monocytes and neutrophils. This chemotactic activity was inhibited by antisera to either H. pylori whole bacteria or H. pylori-derived urease. Moreover, surface proteins extracted from H. pylori and purified H. pylori urease (a major component of the surface proteins) exhibited dose-dependent, antibody-inhibitable chemotactic activity. In addition, a synthetic 20-amino acid peptide from the NH2-terminal portion of the 61-kD subunit, but not the 30-kD subunit, of urease exhibited chemotactic activity for monocytes and neutrophils, localizing the chemotactic activity, at least in part, to the NH2 terminus of the 61-kD subunit of urease. The ability of leukocytes to chemotax to H. pylori surface proteins despite formyl-methionyl-leucyl-phenylalanine (FMLP) receptor saturation, selective inhibition of FMLP-mediated chemotaxis, or preincubation of the surface proteins with antiserum to FMLP indicated that the chemotaxis was not FMLP mediated. Finally, we identified H. pylori surface proteins and urease in the lamina propria of gastric antra from patients with H. pylori-associated gastritis but not from uninfected subjects. These findings suggest that H. pylori gastritis is initiated by mucosal absorption of urease, which expresses chemotactic activity for leukocytes by a mechanism not involving N-formylated oligopeptides
  499. Nachamkin, Irving; Blaser, Martin J; Tompkins, Lucy S. Campylobacter jejuni : current status and future trends. Washington, DC : American Society for Microbiology, 1992. x, 300 p. ; 26 cm..     
  500. Parsonnet J; Blaser MJ; Perez-Perez GI; Hargrett-Bean N; Tauxe RV. "Symptoms and risk factors of Helicobacter pylori infection in a cohort of epidemiologists". Gastroenterology. 1992 Jan;102(1):41-46 (MEDL:1727779 #19233)    

    To identify symptoms and risk factors associated with Helicobacter pylori infection, a cohort of 341 epidemiologists was studied. All subjects had one banked serum (collected between 1969 and 1987) and one recent serum sample (collected in 1988) evaluated for H. pylori immunoglobulin G by enzyme-linked immunosorbent assay; subjects provided information on gastrointestinal symptoms and risk factors for gastritis and peptic ulcer disease. Prevalence of infection decreased from the early 1970s to the present. Eleven subjects (3% of the total cohort) seroconverted during the interval between serum samples, giving a crude conversion rate of 0.49% per person-year (95% confidence interval, 0.3-0.9). Nonreactors on the 1988 serum sample described similar symptoms to reactors. However, subjects who seroconverted in the interval between the two serum samples were more likely than either persistent nonreactors [relative risk (RR), 4.1] or persistent reactors (RR, 3.7) to have experienced upper gastrointestinal symptoms in the interval years. Consumption of caffeinated beverages (RR, 4.6) and residence in the northeastern United States (RR, 5.3) seemed to increase risk for infection. Because pain was similarly common in H. pylori-positive and -negative patients, H. pylori cannot be summarily accepted as the cause of dyspeptic symptoms even when infection is confirmed
  501. Perez-Perez GI; Olivares AZ; Cover TL; Blaser MJ. "Characteristics of Helicobacter pylori variants selected for urease deficiency". Infection & immunity. 1992 Sep;60(9):3658-3663 (MEDL:1500174 #19224)    

    The urease of Helicobacter pylori is suspected to play a role in the pathogenesis of gastritis. Although all clinical isolates of H. pylori are urease positive (U+), we have selected and characterized several spontaneously arising urease-negative (U-) variants from wild-type strain 60190. Urease-negative variants were identified by growth in medium containing 60 mM urea and arose at a frequency of 10(-5) to 10(-6). The urease activity of the wild-type strain inhibited growth of this strain in the presence of 60 mM urea. U- variants retained the U- phenotype for more than 100 passages on medium with or without urea. The urease activities of the original U+ and derived U- cells were 9.55 to 16.7 and 0.01 to 0.17 U/mg of protein, respectively. Colonial growth and other biochemical characteristics were identical for the strains. U- variants showed three classes of whole-cell sodium dodecyl sulfate-polyacrylamide gel electrophoresis profiles: (i) identical to U+; (ii) change in the migration of the 61-kDa urease subunit; and (iii) lack of 61- and 30-kDa subunits. These differences were confirmed by immunoblotting and by protein separation using fast protein liquid chromatography. The U+ strain but not U- variants tolerated exposure to pH 4.0 for 60 min in the presence of urea. Supernatants of the U+ strain and U- variants contained vacuolating cytotoxin activity for HeLa cells in similar titers. By enzyme-linked immunosorbent assay, human serum samples recognized water extract from the U+ strain significantly better than extract from a U- variant lacking urease subunits. In conclusion, this study demonstrates that U- H. pylori variants may arise spontaneously, that urease activity enhances survival at acid pH, and that urease and cytotoxin activities are disparate phenotypes
  502. Perez-Perez, Guillermo I; Taylor, David N; Echerverria, Peter D; Blaser, Martin J. Lack of Evidence of Enterotoxin Involvement in Pathogenesis of Campylobacter Diarrhea. [Alexandria, VA] : Ft. Belvoir Defense Technical Information Center, 1992. 12 p..   

    Several Campylobacter species are now recognized as important pathogens causing human diarrheal disease (7,8), but specific virulence mechanisms are not yet well defined. Campylobacter jejuni and C. coli infection may result in classical dysentery with fever and the presence of blood and Leukocytes in the stools, suggestive of an invasive process or cytotoxin production (3,27,37,38). Campylobacter diarrhea may also be associated with episodes of loose or watery stools and the absence of fever, consistent with the effect of a choleralike enterotoxin
  503. Shandera WX; Tormey MP; Blaser MJ. "An outbreak of bacteremic Campylobacter jejuni infection". Mount Sinai journal of medicine. 1992 Jan;59(1):53-56 (MEDL:1734239 #19232)    

    During September 1980, an outbreak of bacteremic Campylobacter jejuni infection occurred in metropolitan Los Angeles. The outbreak was recognized when blood cultures obtained from 11 previously healthy persons with acute febrile illnesses (characterized in over 80% by fever, diarrhea, and headaches) were positive for C. jejuni. All recovered after an illness that lasted a mean of 8 days. A surveillance system failed to reveal a concomitant outbreak of gastroenteritis. Isolates had identical biochemical characteristics, susceptibility patterns to antimicrobial agents, and serotypes. Isolates from 2 patients were found to be susceptible to bactericidal activity of normal human serum. When bacteremic case-patients were matched with healthy controls, a significant association (p less than 0.05, odds ratio 10) between illness and consumption of processed turkey was established. Although turkey was not available for culture, and processing of turkey theoretically destroys Campylobacter, turkey carcasses are known to be heavily contaminated with the pathogen
  504. Shandera, Wayne X; Tormey, Michael P; Blaser, Martin J. An outbreak of bacteremic campylobacter jejuni infection. [S.l.] : Ft. Belvoir Defense Technical Information Center, 1992. 5 p..   

    During September 1980, an outbreak of bacteremic Campylobacter jejuni infection occurred in metropolitan Los Angeles. The outbreak was recognized when blood cultures obtained from 11 previously healthy persons with acute febrile illnesses (characterized in over 80% by fever, diarrhea, and headaches) were positive for C . jejuni. All recovered after an illness that lasted a mean of 8 days. A surveillance system failed to reveal a concomitant outbreak of gastroenteritis. Isolates had identical biochemical characteristics, susceptibility patterns to antimicrobial agents, and serotypes. Isolates from 2 patients were found to be susceptible to bactericidal activity of normal human serum. When bacteremic case-patients were matched with healthy controls, a significant association (p < 0.05, odds ratio 10) between illness and consumption of processed turkey was established. Although turkey was not available for culture, and processing of turkey theoretically destroys Campylobacter, turkey carcasses are known to be heavily contaminated with the pathogen
  505. Tummuru MK; Blaser MJ. "Characterization of the Campylobacter fetus sapA promoter: evidence that the sapA promoter is deleted in spontaneous mutant strains". Journal of bacteriology. 1992 Sep;174(18):5916-5922 (MEDL:1522068 #19222)    

    Wild-type Campylobacter fetus cells possess S-layer proteins (S+ phenotype), whereas after laboratory passage, spontaneous stable mutants that do not express these proteins (S- phenotype) arise. To determine the molecular mechanisms by which C. fetus changes to the S- phenotype, we studied wild-type strain 23D, from which the sapA gene encoding the 97-kDa S-layer protein has been cloned, and strain 23B, a spontaneous S- mutant. We compared these strains with another pair of strains, LP (S+) and HP (S-). Southern analysis with the cloned sapA gene as a probe indicated that both pairs of strains have multiple sapA homologs. Using gene disruption and replacement techniques, we constructed an isogenic strain of 23D that differed only in sapA expression (strain 23D:401:1). A 6.0-kb HindIII fragment from 23D:401:1 containing 3.4 kb of sapA upstream region then was cloned into pBluescript to produce pBG101. Nucleotide sequence analysis of sapA upstream region revealed a consensus promoter at -121 bp from the translational start site. Primer extension analysis placed a single in vivo transcription initiation site at the -114-bp position of sapA. A DNA probe derived from the sapA promoter region hybridized to a 5.5-kb HindIII fragment of chromosomal DNA from strain 23D but not to DNA from strain 23B. Northern RNA blot analysis showed no sapA mRNA in strain 23B. These data indicate that the lack of S-layer protein expression in spontaneous mutant strains is caused by the deletion of promoter sequences
  506. Yang LY; Pei ZH; Fujimoto S; Blaser MJ. "Reattachment of surface array proteins to Campylobacter fetus cells". Journal of bacteriology. 1992 Feb;174(4):1258-1267 (MEDL:1735716 #19229)    

    Campylobacter fetus strains may be of serotype A or B, a property associated with lipopolysaccharide (LPS) structure. Wild-type C. fetus strains contain surface array proteins (S-layer proteins) that may be extracted in water and that are critical for virulence. To explore the relationship of S-layer proteins to other surface components, we reattached S-layer proteins onto S- template cells generated by spontaneous mutation or by serial extractions of S+ cells with water. Reattachment occurred in the presence of divalent (Ba2+, Ca2+, Co2+, and Mg2+) but not monovalent (H+, NH4+, Na+, K+) or trivalent (Fe3+) cations. The 98-, 125-, 127-, and 149-kDa S-layer proteins isolated from strains containing type A LPS (type A S-layer protein) all reattached to S- template cells containing type A LPS (type A cells) but not to type B cells. The 98-kDa type B S-layer protein reattached to SAP- type B cells but not to type A cells. Recombinant 98-kDa type A S-layer protein and its truncated amino-terminal 65- and 50-kDa segments expressed in Escherichia coli retained the full and specific determinants for attachment. S-layer protein and purified homologous but not heterologous LPS in the presence of calcium produced insoluble complexes. By quantitative enzyme-linked immunosorbent assay, the S-layer protein copy number per C. fetus cell was determined to be approximately 10(5). In conclusion, C. fetus cells are encapsulated by a large number of S-layer protein molecules which may be specifically attached through the N-terminal half of the molecule to LPS in the presence of divalent cations
  507. Bessesen MT; Wang E; Echeverria P; Blaser MJ. "Enteroinvasive Escherichia coli: a cause of bacteremia in patients with AIDS". Journal of clinical microbiology. 1991 Nov;29(11):2675-2677 (MEDL:1774287 #19236)    

    A strain of enteroinvasive Escherichia coli was isolated from the blood of a patient with advanced human immunodeficiency virus disease on repeated occasions, associated with severe diarrheal illness. The isolate was killed in vitro by control sera but not by sera collected from the patient before or after his bacterial illnesses
  508. Blaser MJ; Olivares A; Taylor DN; Cornblath DR; McKhann GM. "Campylobacter serology in patients with Chinese paralytic syndrome [Letter]". Lancet. 1991 Aug 3;338(8762):308-308 (MEDL:1677126 #19240)       
  509. Blaser MJ; Perez-Perez GI; Lindenbaum J; Schneidman D; Van Deventer G; Marin-Sorensen M; Weinstein WM. "Association of infection due to Helicobacter pylori with specific upper gastrointestinal pathology". Reviews of infectious diseases. 1991 Jul-Aug;13 Suppl 8(8):S704-S708 (MEDL:1925313 #19242)    

    The association of infection with Helicobacter pylori and antral (type B) gastritis now is clear, and the development of sensitive and specific serologic assays for IgA and IgG allows for diagnosis of this infection by noninvasive means. With use of these assays, we studied the association of infection with H. pylori and four other upper gastrointestinal inflammatory conditions: Barrett's esophagus, pernicious anemia (which accompanies type A gastritis), and duodenal and gastric ulcers. H. pylori was present in only 39% of 41 patients with Barrett's esophagus whose gastric biopsy specimens were examined histologically. Each serologic assay correctly categorized 39 (95.1%) of the 41 patients. For both assays the frequency of seropositivity noted for 58 patients with Barrett's esophagus was not different from that noted for age- and sex-matched healthy controls. Among 40 patients with pernicious anemia, the results of assays for IgA and IgG were positive for 17.5% and 0%, respectively; these prevalences were significantly less than the 50% (IgA) and 40% (IgG) positivities noted for matched controls (P less than .01 for each; McNemar's test). Among 57 patients with documented duodenal or gastric ulcers, the results of assays for IgG and IgA were positive for 100% and 98.2%, respectively; these prevalences were significantly higher than the rate noted for matched controls (P less than .001 for duodenal ulcers and P = .02 for gastric ulcers for IgA assay). These data suggest that infection with H. pylori is strongly associated with duodenal and gastric ulcers, negatively associated with pernicious anemia, and independent of Barrett's esophagus
  510. Blaser, Martin J. Studies of the Outer Membrane Proteins of Campylobacter Jejuni for Vaccine Development. [S.l.] : Ft. Belvoir Defense Technical Information Center, 1991. 14 p..
  511. Cover TL; Puryear W; Perez-Perez GI; Blaser MJ. "Effect of urease on HeLa cell vacuolation induced by Helicobacter pylori cytotoxin". Infection & immunity. 1991 Apr;59(4):1264-1270 (MEDL:2004808 #19246)    

    Concentrated broth culture supernatants from 50 to 60% of Helicobacter pylori strains induce eukaryotic cell vacuolation in vitro. A quantitative assay for cell vacuolation was developed on the basis of the rapid uptake of visibly vacuolated HeLa cells was significantly greater than that of nonvacuolated cells. By using the rapid NRU assay, we sought to determine the roles of H. pylori cytotoxin, urease, and ammonia in the vacuolation of HeLa cells. The NRU of HeLa cells incubated in medium containing ammonium chloride or ammonium sulfate was significantly greater than that of cells incubated in medium alone. In addition, ammonium salts augmented the NRU induced by H. pylori supernatants. The NRU induced by jack bean urease was augmented by the addition of urea to cell culture medium; this suggests that urease-mediated NRU occurs via the generation of ammonia. Acetohydroxamic acid blocked the NRU induced by jack bean urease and urea but failed to block the uptake induced by H. pylori supernatants. Supernatant from a non-urease-producing H. pylori mutant strain induced NRU identical to that of the urease-positive parental strain. These observations indicate that the vacuolating activity in H. pylori supernatants is not mediated solely by urease activity but that it may be potentiated by urease-mediated ammonia production
  512. Dehesa M; Dooley CP; Cohen H; Fitzgibbons PL; Perez-Perez GI; Blaser MJ. "High prevalence of Helicobacter pylori infection and histologic gastritis in asymptomatic Hispanics". Journal of clinical microbiology. 1991 Jun;29(6):1128-1131 (MEDL:1864929 #19244)    

    In this study, we estimated the prevalence of Helicobacter pylori infection and histologic gastritis in 58 asymptomatic Hispanic adult volunteers (mean age, 41 years; 59% male) by endoscopic biopsy of the upper gastrointestinal tract. Forty-six subjects (79%) were found to harbor H. pylori in gastric biopsies, and all had histologic gastritis. Four other subjects were found to have gastritis in the absence of H. pylori. Similar prevalences of H. pylori and gastritis were noted in all age groups and also in American-born and immigrant Hispanics. Biopsy data and serologic studies of H. pylori antibodies correlated well. We conclude that H. pylori infection is an almost universal finding in the gastric mucosa of asymptomatic adult Hispanics, regardless of age. The clinical significance of these findings is unknown, but we speculate that H. pylori and its associated gastritis could have a role in the high incidence of gastric carcinoma in Hispanic populations
  513. Fong TL; Dooley CP; Dehesa M; Cohen H; Carmel R; Fitzgibbons PL; Perez-Perez GI; Blaser MJ. "Helicobacter pylori infection in pernicious anemia: a prospective controlled study". Gastroenterology. 1991 Feb;100(2):328-332 (MEDL:1985031 #19250)    

    Although some authors believe that Helicobacter pylori is the etiologic agent in chronic nonspecific gastritis, it has also been suggested that the bacterium colonizes inflamed mucosa as a secondary event. This study documents the prevalence of H. pylori in 28 patients with pernicious anemia and compares the findings with those of a group of 28 age-, race-, and sex-matched asymptomatic control subjects. All subjects underwent endoscopy with biopsy of the gastric antrum and corpus. A sample of serum was obtained before endoscopy for determination of antibodies (immunoglobulin A and immunoglobulin G) to H. pylori. The prevalence of H. pylori (by biopsy) in patients with pernicious anemia was significantly less than that in controls (11% vs. 71%, P less than 0.0001). All patients with pernicious anemia had abnormalities of corpus histology (inflammation and/or atrophy). In addition, 50% of patients with pernicious anemia had a lymphocytic infiltration of the antrum. All controls with H. pylori had gastritis, 50% having active chronic gastritis. Atrophic changes of the corpus were more commonly found in patients with pernicious anemia (75% vs. 7%, P less than 0.0001). Serology and biopsy results correlated poorly in the patients with pernicious anemia: all 5 patients with positive serology results had negative biopsy results, whereas all 3 patients with positive cultures on biopsy had negative serological studies. In conclusion, patients with pernicious anemia are protected from infection with H. pylori, and H. pylori does not passively colonize mucosa inflamed by an unrelated process
  514. Fujimoto S; Takade A; Amako K; Blaser MJ. "Correlation between molecular size of the surface array protein and morphology and antigenicity of the Campylobacter fetus S layer". Infection & immunity. 1991 Jun;59(6):2017-2022 (MEDL:2037362 #19243)    

    The correlation between the molecular size of the surface layer protein (S protein) and both structure and antigenicity of the Campylobacter fetus surface layer (S layer) was investigated in several clinical strains and their spontaneous variants which produce S proteins of molecular weights (MW) different from those of the parents. Only three molecular sizes of the S proteins were observed (98, 127, and 149 kDa) in the parental and variant strains. Immunologically, the 98-kDa protein and the 149-kDa protein but not the 127-kDa protein were cross-reactive. Freeze-etching analysis showed that the 98-kDa S protein formed a hexagonal arrangement with a 24-nm center-to-center space and that the S proteins with larger MW (127 or 149 kDa) formed tetragonal ones with an 8-nm center-to-center space. Thus, the MW changes of the S proteins seen in the variant strains were associated with both morphological and antigenic changes in S layer. These observations support the hypothesis that the pattern and antigenicity of the C. fetus S layer is determined by the particular type of S protein. Furthermore, the presence of the two different S layer patterns on a single bacterial cell indicates that multiple S proteins can be produced and expressed in a single cell
  515. Kobayashi K; Hamada Y; Blaser MJ; Brown WR. "The molecular configuration and ultrastructural locations of an IgG Fc binding site in human colonic epithelium". Journal of immunology. 1991 Jan 1;146(1):68-74 (MEDL:1984453 #19251)    

    Previously, we discovered a binding site for the Fc region of IgG in human small intestinal and colonic mucosa. The binding site (Fc gamma IBS) appeared to be primarily associated with goblet cells, to consist of greater than 200,000 Da and 78,000 Da components, and to be distinct from leukocyte FcR. In the present work, we used mAb made to colonocyte IgG-binding material to more accurately define the molecular structure and cellular locations of the Fc gamma IBS. In immunoblot and fast protein liquid chromatography analysis, the mAb revealed that the Fc gamma IBS consists of a 110,000- to 140,000-Da component in addition to the two components previously recognized. The greater than 200,000 component may be the critical component for IgG binding, inasmuch as mAb to it but not to the other two components inhibited binding of IgG to colonic sections in vitro. Used in immunoelectron microscopy, the mAb documented that the Fc gamma IBS is present in the endoplasmic reticulum of goblet cells, in the cytoplasmic matrix separating secretory granules of goblet cells, and within the granules themselves; occasionally it has the appearance of being secreted into the intestinal lumen with mucus. The Fc gamma IBS could not be solubilized from colonocyte homogenates by three different detergents, which suggests that it exists in complex with cytoskeletal elements. We speculate that the Fc gamma IBS aids in immunologic protection of the intestine by facilitating interaction between intestinal mucus and antigenic material in the lumen
  516. Lind CD; Blaser MJ. "Helicobacter pylori and duodenal ulceration". Hospital practice (office edition). 1991 Feb;26(2A):'894'-'900' (MEDL:1899674 #19249)    
  517. Mai UE; Perez-Perez GI; Wahl LM; Wahl SM; Blaser MJ; Smith PD. "Soluble surface proteins from Helicobacter pylori activate monocytes/macrophages by lipopolysaccharide-independent mechanism". Journal of clinical investigation. 1991 Mar;87(3):894-900 (MEDL:1847939 #19248)       

    The inflammatory lesions associated with Helicobacter pylori gastritis and duodenitis contain large numbers of mononuclear cells. The close proximity of H. pylori to gastric mucosa suggests that the organism interacts with mononuclear cells, thereby modulating the inflammatory response. To investigate the role of monocytes/macrophages in this response, we examined the effect of whole H. pylori bacteria, H. pylori surface proteins, and H. pylori lipopolysaccharide (LPS) on purified human monocytes. Whole H. pylori and the extracted LPS induced expression of the monocyte surface antigen HLA-DR and interleukin-2 receptors, production of the inflammatory cytokines interleukin 1 and tumor necrosis factor (peptide and messenger RNA), and secretion of the reactive oxygen intermediate superoxide anion. Since H. pylori in vivo does not invade mucosal tissue, we determined whether soluble constituents of the bacteria could activate monocytes. Soluble H. pylori surface proteins, which are enriched for urease and do not contain LPS, stimulated phenotypic, transcriptional, and functional changes consistent with highly activated monocytes. These findings indicate that H. pylori is capable of activating human monocytes by an LPS-independent as well as an LPS-dependent mechanism. H. pylori activation of resident lamina propria macrophages and monocytes trafficking through the mucosa, leading to the secretion of increased amounts of inflammatory cytokines and reactive oxygen intermediates, could play an important role in mediating the inflammatory response associated with H. pylori gastritis and duodenitis
  518. Morris AJ; Ali MR; Nicholson GI; Perez-Perez GI; Blaser MJ. "Long-term follow-up of voluntary ingestion of Helicobacter pylori". Annals of internal medicine. 1991 Apr 15;114(8):662-663 (MEDL:2003713 #19245)    
  519. Nomura A; Stemmermann GN; Chyou PH; Kato I; Perez-Perez GI; Blaser MJ. "Helicobacter pylori infection and gastric carcinoma among Japanese Americans in Hawaii". New England journal of medicine. 1991 Oct 17;325(16):1132-1136 (MEDL:1891021 #19237)       

    BACKGROUND. Helicobacter pylori are gram-negative spiral bacteria that are associated with chronic gastritis, a known precursor of gastric carcinoma. Persons at high risk for gastric carcinoma have been shown to have a high prevalence of H. pylori infection. METHODS. We studied the relation of H. pylori infection and gastric carcinoma in a cohort of Japanese American men living in Hawaii. The 5908 men were enrolled and examined from 1967 to 1970. By 1989, 109 cases of pathologically confirmed gastric carcinoma had been identified. The store serum of each patient with gastric carcinoma and of each matched control subject were tested for the presence of serum IgG antibody to H. pylori. RESULTS. Ninety-four percent of the men with gastric carcinoma and 76 percent of the matched control subjects had a positive test for H. pylori antibodies, for an odds ratio of 6.0 (95 percent confidence interval, 2.1 to 17.3). As the level of antibody to H. pylori increased, there was a progressive increase in the risk of gastric carcinoma (P for trend = 0.0009). The association was strong even for men in whom the diagnosis was made 10 or more years after the serum sample was obtained (odds ratio, 10.5; 95 percent confidence interval, 2.5 to 44.8). CONCLUSIONS. Infection with H. pylori is strongly associated with an increased risk of gastric carcinoma. However, most persons infected with H. pylori will never have gastric carcinoma. Therefore, other factors that increase the risk of gastric carcinoma among persons infected with H. pylori need to be identified
  520. Pei ZH; Ellison RT; Blaser MJ. "Identification, purification, and characterization of major antigenic proteins of Campylobacter jejuni". Journal of biological chemistry. 1991 Sep 5;266(25):16363-16369 (MEDL:1885571 #19239)    

    Evidence from developing countries and volunteer studies indicates that immunity to Campylobacter jejuni and Campylobacter coli may be acquired, but the antigenic basis for this protection is poorly defined. We have purified to homogeneity four proteins with molecular weights of 28,000 (PEB1), 29,000 (PEB2), 30,000 (PEB3), and 31,000 (PEB4) from epidemic C. jejuni strain 81-176 using acid extraction and sequential ion-exchange, hydrophobic interaction, and gel filtration chromatography. The relative amino acid compositions of these four proteins are similar. NH2-terminal sequence analysis indicates that all four proteins are different, although the first 35 amino acids of PEB2 and PEB3 are 51.4% homologous. Isoelectric focusing showed that all four are basic proteins with pI of 8.5 for PEB1 protein and greater than 9.3 for the others. Use of the purified proteins as antigens in an IgG enzyme-linked immunosorbent assay (ELISA) found that seroconversion to the PEB1 or PEB3 proteins occurred in 15 of 19 patients with sporadic C. jejuni or C. coli infection. In comparison, only two, six, and 14 of these patients seroconverted to PEB2, PEB4, or the acid extract antigen. In an ELISA with whole bacterial cells as antigens, antiserum to the acid-extracted antigens showed broad recognition of C. jejuni, C. coli, C. fetus, C. lari, and Helicobacter pylori. Antiserum to PEB1 recognized all 35 C. jejuni and all 15 C. coli strains but none of the isolates of the other three bacterial species. The PEB1 and PEB3 proteins appear to be candidate antigens for both a Campylobacter vaccine and for serological assays for the pathogen
  521. Pei, Zhiheng; Ellison, Richard T III; Blaser, Martin J. Identification, Purification and Characterization of Major Antigenic Proteins of Campylobacter jejuni. [S.l.] : Ft. Belvoir Defense Technical Information Center, 1991. 9 p..   

    Evidence from developing countries and volunteer studies indicates that immunity to Campylobacter jejuni and Campylobacter coli maybe acquired, but the antigenic basis for this protection is poorly defined. We have purified to homogeneity four proteins with molecular weights of 28,000 (PEB1), 29,000 (PEB2) , 30,000 (PEB3), and 31,000 (PEB4) from epidemic C. jejuni strain 81-176 using acid extraction and sequential ion-exchange, hydrophobic interaction, and gel filtration chromatography. The relative amino acid compositions of these four proteins are similar NH2-terminal sequence analysis indicates that all four proteins are different, although the first 35 amino acids of PEB2 and PEB3 are 51.4% homologous
  522. Perez-Perez GI; Witkin SS; Decker MD; Blaser MJ. "Seroprevalence of helicobacter pylori infection in couples". Journal of clinical microbiology. 1991 Mar;29(3):642-644 (MEDL:2037687 #19247)    

    We investigated the prevalence of Helicobacter pylori in 277 couples attending an infertility clinic. In total, 96 (17.3%) of the 554 persons were positive; in only 18 (6.6%) of the couples were both persons seropositive. Age was an important predictor for H. pylori infection. For 177 couples, information regarding birthplace, duration of cohabitation, history of ulcer or gastritis, and use of antacid or bismuth compounds was available. None of these variables correlated with H. pylori infection except place of birth; 69.1% of 55 persons born outside the United States were seropositive compared with 8.7% of persons born within the United States (P less than 0.0001). Being a partner of an H. pylori-infected person increased the risk of being infected; however, by multiple logistic regression analysis this effect was entirely explained by age and national origin. These data suggest that in young sexually active adults, person-to-person transmission of H. pylori does not occur or at most occurs infrequently
  523. Polish LB; Douglas JM; Davidson AJ; Perez-Perez GI; Blaser MJ. "Characterization of risk factors for Helicobacter pylori infection among men attending a sexually transmitted disease clinic: lack of evidence for sexual transmission". Journal of clinical microbiology. 1991 Oct;29(10):2139-2143 (MEDL:1939565 #19238)    

    The mechanism of transmission of Helicobacter pylori is unknown. To investigate the role of sexual behavior and demographic factors in the acquisition of H. pylori infection, we evaluated the seroprevalence of antibody to H. pylori in 370 men attending an urban sexually transmitted diseases clinic. Sera from the following three groups were analyzed by enzyme-linked immunosorbent assay for H. pylori-specific immunoglobulin G: 78 human immunodeficiency virus (HIV)-seropositive homosexual men, 102 HIV-seronegative homosexual men, and 190 HIV-seronegative heterosexual men. Overall, the seroprevalence of H. pylori was 100 of 370 men (27%), with rates of 18% in HIV-seropositive homosexual men and 20% in HIV-seronegative homosexual men versus 35% in heterosexual men (P less than 0.005, chi 2 test). By ethnic group, 21 (12%) of 181 Caucasian men, 40 (41%) of 97 black men, and 37 (43%) of 87 Hispanic men were seropositive (P less than 0.001, chi 2 test). Multivariate analysis revealed that race was associated with H. pylori seropositivity independent of HIV status, sexual preference, or age. There was no relationship between H. pylori seropositivity and the number of lifetime sexual partners or previous sexually transmitted diseases. Three HIV-seropositive men with H. pylori immunoglobulin G had essentially identical antibody titers over 8 to 16 months of follow-up. In conclusion, black and Hispanic men have significantly higher H. pylori seroprevalence rates than do Caucasian men, but neither sexual behavior nor HIV infection influences the presence or persistence of H. pylori antibody. Further evaluation of the factors associated with these ethnic differences may lead to a better understanding of H. pylori acquisition and transmission
  524. Talley NJ; Newell DG; Ormand JE; Carpenter HA; Wilson WR; Zinsmeister AR; Perez-Perez GI; Blaser MJ. "Serodiagnosis of Helicobacter pylori: comparison of enzyme-linked immunosorbent assays". Journal of clinical microbiology. 1991 Aug;29(8):1635-1639 (MEDL:1761685 #19241)    

    Enzyme-linked immunosorbent assays (ELISAs) have been developed to diagnose Helicobacter pylori infection. However, the methods are not standardized. We therefore prospectively evaluated the sensitivities and specificities of ELISAs developed in the United States and the United Kingdom in a study population comprising 41 consecutive symptomatic outpatients and 35 volunteers. At endoscopy, multiple biopsies were obtained for histology and culture and stained sections were graded for chronic gastritis, active chronic gastritis, and density of H. pylori. Serum samples were analyzed for H. pylori by ELISA. The first set of assays for immunoglobulin G (IgG) and IgA used a pool of sonicated isolates of H. pylori from five patients in the United States (antigen A). The second set of assays, developed in the United Kingdom, used three different antigens: antigen 1, an acid-extractable surface antigen; antigen 2, an acid-extractable antigen from an aflagellate variant; and antigen 3, a urease-containing fraction. Cutoff scores for positive results were determined a priori on the basis of previous serological studies. There was close agreement between histology and culture. In the study population, 36% of the individuals were H. pylori positive. The diagnostic value of the different ELISAs were highly comparable, and the crude antigens performed as well as the more purified antigens. The antigen A IgG had a sensitivity and specificity of 96 and 94%, respectively; the values for antigen 1 were 93 and 96%, respectively. The antigen A IgA and antigen 3 assays were the least sensitive tests.(ABSTRACT TRUNCATED AT 250 WORDS)
  525. Talley NJ; Zinsmeister AR; Weaver A; DiMagno EP; Carpenter HA; Perez-Perez GI; Blaser MJ. "Gastric adenocarcinoma and Helicobacter pylori infection". Journal of the National Cancer Institute. 1991 Dec 4;83(23):1734-1739 (MEDL:1770552 #19235)       

    Helicobacter pylori infection, thought to be causally related to chronic gastritis, may also be associated with an increased risk of gastric cancer. To determine whether an association with gastric cancer does exist, we retrospectively evaluated serum samples from 69 patients with histologically confirmed gastric adenocarcinoma (32 with cancer at the cardia and 37 with cancer at other sites) and from 218 patients with one of three categories of nongastric cancers, with other gastric cancers, or with benign gastric neoplasms. These samples were compared with samples from 252 cancer-free control subjects, a group comprising 76 asymptomatic volunteers and 176 persons with nonmalignant disorders. Serum samples collected from cancer patients prior to surgery and from cancer-free controls were tested for antibodies to H. pylori by using a highly sensitive and specific IgG enzyme-linked immunosorbent assay. The risk of H. pylori infection in the case patients relative to the control subjects was estimated with the use of multivariate logistic regression analysis to adjust for potential confounding variables. Antibodies to H. pylori were detected in 65% of the patients with noncardia gastric cancer but in only 38% of the patients with gastric cancer located at the cardia. A significant association was found between H. pylori infection and noncardia gastric cancer (odds ratio = 2.67; 99% confidence interval = 1.01-7.06). Within the subset of patients with noncardia gastric cancer, a statistically nonsignificant tendency existed for those with the intestinal versus the diffuse histologic type of noncardia gastric cancer to have a higher risk of H. pylori infection. Our results support the hypothesis of a relationship between H. pylori infection and the development of noncardia gastric adenocarcinoma
  526. Taylor DN; Blaser MJ. "The epidemiology of Helicobacter pylori infection". Epidemiologic reviews. 1991;13(1):42-59 (MEDL:1765119 #19252)    

    The evidence that H. pylori causes gastritis in humans comes from both primary and secondary observations. The most important primary observations are the human volunteer studies, the animal models, and the treatment studies with antimicrobial agents. Supporting information comes from studies showing the specific association of H. pylori infection with type B gastritis and with gastric (but not intestinal) epithelial cells; the specific ultrastructural lesions, including adherence pedestals; the ubiquity and stability of the immune response; the response to bismuth treatment; and the association with epidemic gastritis and hypochlorhydria. It is important to note that all of Koch's postulates have been fulfilled, and despite nearly universal initial skepticism, no evidence exists against the hypothesis that H. pylori plays an etiologic role in type B gastritis. Therefore, it is reasonable to conclude that H. pylori is a pathogen in humans. The known features of H. pylori infection are listed in. Infection is chronic and common throughout the world, with a higher prevalence in developing countries than in developed countries. The prevalence of H. pylori infection increases with age in parallel with that of gastritis. Acquisition of H. pylori infection does not appear to have any seasonality, and infection is equally common among men and women. Without a significant animal or environmental reservoir for human strains of H. pylori, person-to-person contact appears to be the most likely mode of transmission. Exactly how the organism is transmitted from the stomach of one person to that of another remains unclear. Also unknown are the factors which determine who becomes ill after infection; why one person has gastritis alone while another person develops a duodenal ulcer; and how the traditional risk factors for ulcer disease, such as smoking, aspirin, and alcohol, interact with H. pylori infection. Finally, the long term neoplastic consequences of infection must be understood. Further elucidation of the natural history of H. pylori and the consequences of H. pylori infection is the most important goal for future study
  527. Bessesen MT; Luo QA; Rotbart HA; Blaser MJ; Ellison RT. "Detection of Listeria monocytogenes by using the polymerase chain reaction". Applied & environmental microbiology. 1990 Sep;56(9):2930-2932 (MEDL:2125817 #19258)    

    A method was developed for detection of Listeria monocytogenes by polymerase chain reaction amplification followed by agarose gel electrophoresis or dot blot analysis with a 32P-labeled internal probe. The technique identified 95 of 95 L. monocytogenes strains, 0 of 12 Listeria strains of other species, and 0 of 12 non-Listeria strains
  528. Blaser MJ. "Epidemiology and pathophysiology of Campylobacter pylori infections". Reviews of infectious diseases. 1990 Jan-Feb;12 Suppl 1(6):S99-106 (MEDL:2406864 #19269)    

    Since the first isolation of Campylobacter pylori in Australia in 1982, this bacterium has been isolated from persons in all parts of the world. Although initially recognized in patients with gastrointestinal symptoms, C. pylori can also be isolated from apparently asymptomatic persons. C. pylori infection is infrequent in young children in developed countries; during adulthood C. pylori infection becomes progressively more frequent, a phenomenon that parallels the age distribution of type B gastritis. In developing countries infection is more common and begins earlier. Infection, once acquired, appears to persist, possibly for life, but the mode of transmission to humans is unknown. C. pylori is well adapted for survival in the gastric milieu, but whether C. pylori plays a causative role in gastritis is of critical importance. Favoring this hypothesis are the results of inoculation studies in volunteers and animals in which challenge with C. pylori resulted in persistent infection and histologic lesions. Treatment studies with antimicrobial agents indicate that removal of C. pylori is associated with improvement in histologic appearance of affected tissues and that when infection recurs the histologic appearance worsens. The mechanisms by which C. pylori infection may cause gastritis are unknown but possibilities include production of cytotoxin, degradation of physiologic defenses against acid-pepsin damage, and adherence to epithelial cells
  529. Blaser MJ. "Helicobacter pylori and the pathogenesis of gastroduodenal inflammation". Journal of infectious diseases. 1990 Apr;161(4):626-633 (MEDL:2181029 #19265)       

    Helicobacter pylori is a newly discovered gram-negative bacterium that lives in the human stomach and duodenum. Infection with this organism is strongly associated with type B antral gastritis and with peptic ulcer disease. Recent evidence from human volunteer studies, therapeutic trials with antimicrobial agents, and experiments with animal models indicates that H. pylori plays an etiologic role in the pathogenesis of type B gastritis. Gastric metaplasia is observed in virtually all patients with duodenal ulceration and may be the target tissue for these bacteria in the duodenum. Patients in whom H. pylori can no longer be identified after ulcer therapy remain in remission for significantly longer than do patients in whom the organism can be found. The data concerning an etiologic role of H. pylori in duodenal ulcer are suggestive but not yet conclusive. Present antimicrobial therapy can suppress but usually cannot eliminate H. pylori
  530. Blaser MJ; Gotschlich EC. "Surface array protein of Campylobacter fetus. Cloning and gene structure". Journal of biological chemistry. 1990 Nov 5;265(31):19372-19372 (MEDL:2229082 #19255)    
  531. Blaser MJ; Gotschlich EC. "Surface array protein of Campylobacter fetus. Cloning and gene structure". Journal of biological chemistry. 1990 Aug 25;265(24):14529-14535 (MEDL:2387868 #19259)    

    The high molecular mass (97-149 kDa) surface array proteins (SAP) of Campylobacter fetus are critical to virulence. We created a bank of 160,000 random 1.0-6.5-kilobase (kb) chromosomal DNA fragments of C. fetus strain 84-32 (23D) using lambda gt11. Screening this bank in Escherichia coli Y1090 with antibody raised against purified SAP permitted isolation and purification of a clone with a 4.0-kb insert. Subcloning this insert in the E. coli vector, pUC9, permitted expression of a protein of approximately 100 kDa, not fused with beta-galactoside or inducible by isopropyl-beta-D-thiogalactopyranoside. Digestion with restriction endonucleases, and construction of deletion mutations indicated that the gene extended over 2.8 kb, proceeding toward the start of the beta-galactosidase gene. Taking advantage of a unique PstI site at 1.7 kb, we subcloned PstI-EcoRI fragments in both orientations into M13 vectors, then generated and sequenced 48 deletion mutants. In the 3974-base insert, an open reading frame, beginning at nucleotide 24 and terminating at 2825, was found to encode a 933-amino acid polypeptide having a calculated molecular mass of 96,758 daltons. The first 20 amino acids exactly match those determined from amino-terminal sequencing, indicating that this protein is secreted without a leader sequence. The deduced amino acid composition matches that of the purified SAP. We identified a ribosomal binding site 9 bases upstream, and a putative transcription terminator (delta G = -12.4) 21 bases downstream. There is partial homology of primary and secondary structure with five other bacterial S-layer proteins
  532. Cover TL; Dooley CP; Blaser MJ. "Characterization of and human serologic response to proteins in Helicobacter pylori broth culture supernatants with vacuolizing cytotoxin activity". Infection & immunity. 1990 Mar;58(3):603-610 (MEDL:2307514 #19267)    

    Helicobacter pylori infection is strongly associated with histologic gastritis and peptic ulcer disease. Broth culture supernatants from a subset of H. pylori strains induce vacuolization in cultured cells, a phenomenon that has been attributed to cytotoxin activity. Concentrated culture supernatants from 15 of 28 (53.6%) H. pylori strains tested induced vacuolization in HeLa cells in titers ranging from 1:10 to 1:180. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis and silver staining of supernatants from these 28 strains and 2 control strains demonstrated an 82-kilodalton (kDa) protein band in 3 of 16 supernatants with vacuolizing activity, but in none of 14 supernatants without vacuolizing activity. By immunoblotting with human sera, a 128-kDa band was recognized in all 16 supernatants with vacuolizing activity, compared with 9 of 14 (64%) supernatants without vacuolizing activity (P = 0.014). Serologic recognition of the 128-kDa band in H. pylori culture supernatants was more prevalent among persons infected with vacuolizing H. pylori strains than among persons infected with nonvacuolizing strains, but the difference was not statistically significant (80 versus 45%; P = 0.079); human serologic recognition of the 82-kDa band was less common. The 128-kDa band was recognized by 100% of 31 serum samples from H. pylori-infected patients with duodenal ulcer disease, compared with 60.8% of 74 serum samples from H. pylori-infected persons without peptic ulcer disease (P = 0.0001). These data indicate that antigenic 128- and 82-kDa proteins are present in H. pylori broth culture supernatants with vacuolizing activity and that serologic responses to the 128-kDa protein are more prevalent among H. pylori-infected persons with duodenal ulceration than among infected persons without peptic ulceration
  533. Cover TL; Perez-Perez GI; Blaser MJ. "Evaluation of cytotoxic activity in fecal filtrates from patients with Campylobacter jejuni or Campylobacter coli enteritis". FEMS microbiology letters. 1990 Aug;58(3):301-304 (MEDL:2227365 #19261)    

    We sought to determine the prevalence of cytotoxic activity in fecal filtrates from persons with C. jejuni or C. coli enteritis. Stool specimens were collected from 20 persons with C. jejuni or C. coli enteritis, 20 persons with acute diarrheal illnesses of other causes, and 9 healthy, asymptomatic persons. Fecal filtrates were then incubated with Chinese hamster ovary (CHO) or HeLa cells. The fecal filtrate from 1 of the 20 (5%) persons with Campylobacter enteritis was cytotoxic for HeLa cells at a titer of 1:40, and 10 (50%) were cytotoxic for CHO cells at maximum titers of 1:20. Cytotoxic activity for CHO cells at a median titer of 1:20 was also present in 40% of the fecal filtrates from persons with diarrhea due to causes other than Campylobacter enteritis, and in 33% of filtrates from healthy, asymptomatic persons. The observed low level of cytotoxicity in fecal filtrates from all patient groups studied likely resulted from non-specific factors, unrelated to the pathogenesis of Campylobacter enteritis
  534. Cover, Timothy L; Perez-Perez, Guillermo I; Blaser, Martin J. Evaluation of Cytotoxic Activity in Fecal Filtrates from Patients with Campylobacter jejuni or Campylobacter coli enteritis. [Alexandria, VA] : Ft. Belvoir Defense Technical Information Center, 1990. 6 p..   

    Although Campylobacter jejuni and C. coli are important causes of diarrheal illness worldwide, the pathophysiologic mechanisms whereby these organisms cause human disease remain poorly understood (1). Cytotoxic activity has been demonstrated in culture supernatants of C. jejuni and C. coli grown in vitro (2-7), but the in vivo relevance of these observations is not clear. We therefore sought to detect cytotoxic activity in fecal filtrates from persons with campylobacter enteritis. Fecal filtrates from persons with diarrhea due to other causes and from asymptomatic healthy persons were tested as controls
  535. Drumm B; Perez-Perez GI; Blaser MJ; Sherman PM. "Intrafamilial clustering of Helicobacter pylori infection". New England journal of medicine. 1990 Feb 8;322(6):359-363 (MEDL:2300088 #19268)       

    Colonization of the gastric antrum by Helicobacter pylori (formerly Campylobacter pylori) has been associated with primary gastritis. We determined the frequency of colonization by H. pylori in gastric-antrum biopsy specimens from 93 children undergoing gastroscopy for the evaluation of upper gastrointestinal symptoms. We also determined H. pylori IgG antibody levels by enzyme-linked immunosorbent assay in coded serum samples from these children, family members, and control subjects of comparable ages. Among 27 children with primary, or unexplained, gastritis, H. pylori was identified by silver staining in 24 biopsy specimens and by culture in 22; specific antibodies were present in 23 children (96 percent). Three children with unexplained gastritis had no evidence of H. pylori in the antrum, nor did any of 13 children with secondary gastritis or any of 53 children with normal antral histologic features; specific antibodies were present in only 1 of these 69 children. H. pylori antibody was detected in 25 of 34 parents of colonized children, but in only 8 of 33 parents of noncolonized children (P less than 0.001). Of 22 siblings of children colonized by H. pylori, 18 had specific antibodies, as compared with only 5 of 37 controls (P less than 0.001). We conclude that H. pylori-specific IgG antibodies are associated with bacterial colonization of the gastric antrum by this organism. The intrafamilial clustering of H. pylori infection suggests that there may be person-to-person spread of these bacteria
  536. Dunn BE; Campbell GP; Perez-Perez GI; Blaser MJ. "Purification and characterization of urease from Helicobacter pylori". Journal of biological chemistry. 1990 Jun 5;265(16):9464-9469 (MEDL:2188975 #19262)    

    Urease was purified 112-fold to homogeneity from the microaerophilic human gastric bacterium, Helicobacter pylori. The urease isolation procedure included a water extraction step, size exclusion chromatography, and anion exchange chromatography. The purified enzyme exhibited a Km of 0.3 +/- 0.1 mM and a Vmax of 1,100 +/- 200 mumols of urea hydrolyzed/min/mg of protein at 22 degrees C in 31 mM Tris-HCl, pH 8.0. The isoelectric point was 5.99 +/- 0.03. Molecular mass estimated for the native enzyme was 380,000 +/- 30,000 daltons, whereas subunit values of 62,000 +/- 2,000 and 30,000 +/- 1,000 were determined. The partial amino-terminal sequence (17 residues) of the large subunit of H. pylori urease (Mr = 62,000) was 76% homologous with an internal sequence of the homohexameric jack bean urease subunit (Mr = 90,770; Takashima, K., Suga, T., and Mamiya, G. (1988) Eur. J. Biochem. 175, 151-165) and was 65% homologous with amino-terminal sequences of the large subunits of heteropolymeric ureases from Proteus mirabilis (Mr = 73,000) and from Klebsiella aerogenes (Mr = 72,000; Mobley, H. L. T., and Hausinger, R. P. (1989) Microbiol. Rev. 53, 85-108). The amino-terminal sequence (20 residues) of the small subunit of H. pylori urease (Mr = 30,000) was 65 and 60% homologous with the amino-terminal sequences of the subunit of jack bean urease and with the Mr = 11,000 subunit of P. mirabilis urease (Jones, B. D., and Mobley, H. L. T. (1989) J. Bacteriol. 171, 6414-6422), respectively. Thus, the urease of H. pylori shows similarities to ureases found in plants and other bacteria. When used as antigens in an enzyme-linked immunosorbent assay, neither purified urease nor an Mr = 54,000 protein that co-purified with urease by size exclusion chromatography was as effective as crude preparations of H. pylori proteins at distinguishing sera from persons known either to be infected with H. pylori or not
  537. Fauchere JL; Blaser MJ. "Adherence of Helicobacter pylori cells and their surface components to HeLa cell membranes". Microbial pathogenesis. 1990 Dec;9(6):427-439 (MEDL:2097496 #19253)       

    Four Helicobacter pylori strains were used to develop in vitro methods to assess adherence to HeLa cells. Using direct detection by microscopy, adhesion scores increased with the initial bacteria-to-cell ratio. The urease method assessed H. pylori bound to HeLa cells by their urease activity. The percentage of the original inoculum adhering to HeLa cells remained constant for initial ratios from 10(2) to 10(5) bacteria per cell. An ELISA using anti-H. pylori serum assessed whole bacteria or components bound to HeLa cell fractions. By all three methods, the four H. pylori strains were adherent to HeLa cells or membranes whereas Campylobacter fetus and Providencia control strains were not. The adherence of H. pylori whole cells decreased following extraction with saline, water, or glycine buffer and most of the superficial adhering material (SAM) was present in the saline or water extracts. SAM bound better to HeLa membranes than to calf fetuin or bovine serum albumin (BSA); binding was inhibited by preincubation of SAM with HeLa membranes but not with fetuin or BSA or by pretreatment of HeLa membranes with neuraminidase. These data indicate that SAM has a specific receptor on the HeLa cell membranes. By gel exclusion chromatography of bacterial extracts, the most adherent components were found in the fractions which also contained the highest urease activity; these fractions included urease subunit antigens. We conclude that adherence of H. pylori can be assessed by microtiter assays and involves bacterial surface material which co-purifies with urease and is different from the N-acetyl-neuraminyl-lactose binding hemagglutinin
  538. Fogg GC; Yang LY; Wang E; Blaser MJ. "Surface array proteins of Campylobacter fetus block lectin-mediated binding to type A lipopolysaccharide". Infection & immunity. 1990 Sep;58(9):2738-2744 (MEDL:2387622 #19257)    

    Campylobacter fetus strains with type A lipopolysaccharide (LPS) and a surface array protein layer (S+) have been found to be pathogenic in humans and animals. Spontaneous laboratory mutants that lack surface array proteins (S-) are sensitive to the bactericidal activity of normal human serum. The ability of lectins to determine the presence of the S-layer and differentiate LPS type was assessed. We screened 14 lectins and found 3 (wheat germ agglutinin, Bandeiraea simplicifolia II, and Helix pomatia agglutinin) that agglutinated S- C. fetus strains with type A LPS but not S- strains with type B or type C LPS or S+ strains. However, the S+ type A strains were agglutinated after sequential water extraction, heat, or pronase treatment, all of which remove the S-layer, whereas there was no effect on the control strains. Specific carbohydrates for each lectin and purified LPS from a type A C. fetus strain specifically inhibited agglutination of an S- type A strain. In a direct enzyme-linked lectin assay, binding to the S- type A LPS strain was significantly greater than binding to the S+ strain (P = 0.01) or to a Campylobacter jejuni strain (P = 0.008). Consequently, these results indicate that the three lectins bind to the O side chains of C. fetus type A LPS but that the presence of the S-layer on intact cells blocks binding
  539. Glassman MS; Dallal S; Berezin SH; Bostwick HE; Newman LJ; Perez-Perez GI; Blaser MJ. "Helicobacter pylori-related gastroduodenal disease in children. Diagnostic utility of enzyme-linked immunosorbent assay". Digestive diseases & sciences. 1990 Aug;35(8):993-997 (MEDL:2384045 #19260)       

    To evaluate the accuracy of IgG and IgA serological tests in establishing a diagnosis of Helicobacter (Campylobacter) pylori gastric infection, 60 children presenting with chronic abdominal pain were prospectively studied. Endoscopic antral biopsies were obtained and analyzed for the presence of H. pylori using three standard methods: culture and identification of bacterial isolates, microscopic examination for morphologically characteristic bacteria, and urease production by the biopsy specimen. Concomitantly obtained serum samples were analyzed for the presence of IgG and IgA antibodies against H. pylori surface antigens using enzyme-linked immunosorbent assay (ELISA). Thirty-four of 60 (56.6%) had histological evidence of chronic active gastritis, eight of whom (13.3%) also had evidence of H. pylori infection by at least one criteria. Six of the eight infected patients had H. pylori demonstrated by all three methods. Of the eight infected patients, seven had IgG antibodies against H. pylori (sensitivity of 87%) and six had IgA antibodies (sensitivity of 75%). Among the six patients who had H. pylori infection confirmed by all three methods, all had IgG antibodies (sensitivity of 100%). In the patients without evidence of H. pylori infection, the IgG ELISA had a specificity of 96% (50/52), and the IgA ELISA had a specificity of 100% (52/52). Our data suggest that serological testing for the presence of antibodies against H. pylori may be a useful diagnostic tool in screening children with chronic abdominal pain for the presence of gastric infection with H. pylori
  540. Jacoby GA; Blaser MJ; Santanam P; Hachler H; Kayser FH; Hare RS; Miller GH. "Appearance of amikacin and tobramycin resistance due to 4'-aminoglycoside nucleotidyltransferase [ANT(4')-II] in gram-negative pathogens". Antimicrobial agents & chemotherapy. 1990 Dec;34(12):2381-2386 (MEDL:1965106 #19254)       

    Following the use of amikacin as the principal aminoglycoside at a Denver hospital, amikacin resistance appeared first in Pseudomonas aeruginosa and then in Escherichia coli, Klebsiella pneumoniae, and other enteric organisms from debilitated and compromised patients who had spent time in intensive care units and who had been treated with multiple antibiotics, usually including amikacin. In a P. aeruginosa isolate, resistance to amikacin and tobramycin was transferable by the IncP-2 plasmid pMG77, while in E. coli and K. pneumoniae resistance was carried by the transmissible plasmids pMG220, pMG221, and pMG222 belonging to the IncM group. Isolates and transconjugants produced an enzyme with adenyltransferase activity with substrates having a 4'-hydroxyl group, such as amikacin, kanamycin, neomycin, Sch 21768, isepamicin (Sch 21420), or tobramycin, but not with aminoglycosides lacking this target, such as dibekacin, netilmicin, sisomicin, or gentamicin C components. Genes encoding the 4'-aminoglycoside nucleotidyltransferase [ANT(4')] activity were cloned from pMG77, pMG221, and pMG222. A DNA probe prepared from the ANT(4') found in P. aeruginosa hybridized with the ANT(4') determinant found in E. coli. A probe for the ANT(4') from Staphylococcal spp., which differs in its modification of substrates, like dibekacin, that have a 4'- but not a 4'-hydroxyl group, failed to hybridize with the gram-negative ANT(4') determinant, which consequently has been termed ANT(4')-II
  541. Janoff EN; Taylor DN; Echeverria P; Glode MP; Blaser MJ. "Serum antibodies to Giardia lamblia by age in populations in Colorado and Thailand". Western journal of medicine. 1990 Mar;152(3):253-256 (MEDL:2333701 #19266)    

    We measured levels of antibodies to Giardia lamblia by age in serum specimens from persons in Denver, Colorado, and Soongnern, Thailand. Serum levels of immunoglobulin (Ig) G, IgM, and IgA G lamblia-specific antibodies measured by enzyme-linked immunosorbent assay increased substantially during childhood in both geographic areas, although children in Soongnern showed significantly higher mean levels of each antibody class (P less than .05). After adolescence, levels of G lamblia-specific IgM fell steadily with age in both populations. In contrast, specific IgA levels remained elevated throughout life among the Thai but decreased to low levels among adults in Denver. Similarly, rates of carriage of G lamblia were high among children aged 1 to 4 years in Denver and Soongnern (14.3% versus 26.5%, respectively) but were much lower among adults in Denver (0% versus 14%; P less than .01). These data suggest that levels of G lamblia-specific IgM may reflect exposure to the parasite early in life in both areas. Levels of parasite-specific IgA may reflect recurrent exposure to G lamblia in Soongnern, where G lamblia is endemic, but less frequent exposure to the parasite in Denver, where exposure is often episodic
  542. Pei Z; Blaser MJ. "Pathogenesis of Campylobacter fetus infections. Role of surface array proteins in virulence in a mouse model". Journal of clinical investigation. 1990 Apr;85(4):1036-1043 (MEDL:2318963 #19264)       

    We developed a mouse model to compare the virulence of Campylobacter fetus strains with (S-plus) and without (S-minus) surface array protein (S-protein) capsules. In adult HA/ICR mice pretreated with ferric chloride, the LD50 for S-plus strain 84-32 was 43.3 times lower than its spontaneous S-minus mutant 84-54. Seven strains of inbred mice were no more susceptible than the outbred strain. In contrast to the findings with Salmonella typhimurium by others, 3 X 10(7) CFU of strain 84-32 caused 90% mortality in C3H/HeN (LPSn) mice and 40% mortality in C3H/HeJ (LPSd) mice. High-grade bacteremia in HA/ICR mice occurred after oral challenge with S-plus C. fetus strains and continued for at least 2 d, but was not present in any mice challenged with S-minus strains. Bacteremia at 30 min after challenge was 51.6-fold lower in mice pretreated with 10 microliters of rabbit antiserum to purified S-protein than after pretreatment with normal rabbit serum. Challenge of mice with a mixture of S-minus strain 84-54 and free S-proteins at a concentration 31.1-fold higher than found in wild-type strain 84-32 caused 30% mortality, compared with 0% with strain 84-54 or S-protein alone. These findings in a mouse model point toward the central role of the S-protein in the pathogenesis of C. fetus infection. The S-protein is not toxic per se, but enhances virulence when present on the bacterial cell surface as a capsule
  543. Perez-Perez GI; Taylor DN; Bodhidatta L; Wongsrichanalai J; Baze WB; Dunn BE; Echeverria PD; Blaser MJ. "Seroprevalence of Helicobacter pylori infections in Thailand". Journal of infectious diseases. 1990 Jun;161(6):1237-1241 (MEDL:2345304 #19263)       

    Serologic studies in developed countries indicate that Helicobacter (formerly Campylobacter) pylori infection is uncommon until the third decade of life and achieves a peak prevalence of 50% in the seventh decade. In developing countries the epidemiology of H. pylori has not well been described. A sensitive and specific serologic assay for H. pylori infection was validated in Thai patients also studied by culture and histologic examination of biopsy specimens. The prevalence of H. pylori antibodies in persons from a rural Thai community began early (17.5% of children 5-9 years old), increased to 55% during the third decade of life, and peaked (75%) in the 30- to 49-year age group. At a Bangkok orphanage where enteric infections are hyperendemic, 74% of children 1-4 years old were seropositive. This study shows that the prevalence of H. pylori infection in Thailand is higher than in industrialized countries. The high infection rate at the orphanage suggests that person-to-person transmission of H. pylori may be occurring
  544. Strauss RM; Wang TC; Kelsey PB; Compton CC; Ferraro MJ; Perez-Perez G; Parsonnet J; Blaser MJ. "Association of Helicobacter pylori infection with dyspeptic symptoms in patients undergoing gastroduodenoscopy". American journal of medicine. 1990 Oct;89(4):464-469 (MEDL:2220879 #19256)       

    PURPOSE: To determine the prevalence of Helicobacter pylori in patients with non-ulcer dyspepsia and ulcer disease as well as in a control population undergoing endoscopic retrograde cholangiopancreatography (ERCP) for suspected pancreatic or biliary disease. PATIENTS AND METHODS: Forty-six eligible patients undergoing upper endoscopy at Massachusetts General Hospital were studied over a period of 18 months, as well as 24 patients undergoing ERCP for presumed pancreatic or biliary disease. Two biopsy specimens from the fundus and two from the antrum were taken for microbiologic and histopathologic analysis. Sera were examined by enzyme-linked immunoabsorbent assay. All specimens were processed in a blind fashion. Chi-square test with Yates' correction was used for statistical analysis. RESULTS: H. pylori was found in 31 of 46 (67%) study patients and in six of 24 (25%) control patients (by microbiologic or histologic techniques) (p less than 0.01). H. pylori was found in all patients with peptic ulcer disease and in 60% of patients without ulcers. No association between H. pylori and any specific gastrointestinal symptom was observed. H. pylori was identified in the fundus as often as in the antrum, although in the antrum the organism was more often associated with histologic gastritis. Compared with histology, serologic assays for IgG and IgA antibodies to H. pylori had sensitivities of 100% and 94%, and specificities of 86% and 76%, respectively. Reexamination of selected specimens without knowledge of their identity revealed that the specificity of serology exceeded 94% while the sensitivity of histologic and microbiologic studies may have been closer to 80%. CONCLUSIONS: H. pylori was more common in dyspeptic patients than in our control subjects undergoing ERCP. Multiple biopsy sites from fundus and antrum are required to exclude infection. Serologies of IgG and IgA were sensitive and specific for H. pylori, suggesting a possible role for non-endoscopic diagnosis of this infection. The frequent association of H. pylori with active inflammation rather than with quiescent gastritis is consistent with a pathologic role of this organism
  545. Blaser MJ; Brown WR. "Campylobacters and gastroduodenal inflammation". Advances in internal medicine. 1989;34(3):21-42 (MEDL:2644758 #19279)    
  546. Blaser MJ; Hale TL; Formal SB. "Recurrent shigellosis complicating human immunodeficiency virus infection: failure of pre-existing antibodies to confer protection". American journal of medicine. 1989 Jan;86(1):105-107 (MEDL:2642653 #19280)    
  547. Blaser, Martin J. Campylobacter pylori in gastritis and peptic ulcer disease. New York : Igaku-Shoin, 1989. xvi, 256 p. ; 26cm.     
  548. Cover TL; Blaser MJ. "The pathobiology of Campylobacter infections in humans". Annual review of medicine. 1989;40(3):269-285 (MEDL:2658752 #19278)       

    Bacteria of what are now regarded as the genus Campylobacter were first isolated in 1909, but initially were considered as pathogens of animals only. Although the first human infections were reported in 1947, the importance of campylobacters as causes of intestinal illnesses was not widely recognized until the 1970s. C. jejuni and closely related species are now known as leading causes of bacterial gastroenteritis. C. fetus causes systemic diseases, primarily in compromised hosts. Most recently, C. pylori has been associated with antral gastritis and peptic ulcer disease. The pathogenic mechanisms for these three related organisms, while still being elucidated, are now known to be substantially different
  549. Cover TL; Dunn BE; Ellison RT; Blaser MJ. "Vibrio cholerae wound infection acquired in Colorado [Comment]". Journal of infectious diseases. 1989 Dec;160(6):1083-1083 (MEDL:2584756 #19271)       
  550. Dooley CP; Cohen H; Fitzgibbons PL; Bauer M; Appleman MD; Perez-Perez GI; Blaser MJ. "Prevalence of Helicobacter pylori infection and histologic gastritis in asymptomatic persons". New England journal of medicine. 1989 Dec 7;321(23):1562-1566 (MEDL:2586553 #19270)       

    We estimated the prevalences of Helicobacter pylori (formerly called Campylobacter pylori) infection and histologic gastritis in 113 asymptomatic persons, using endoscopic biopsy of the gastric antrum and corpus. Unsuspected lesions, mainly mucosal erosions, were revealed at endoscopy in 16 subjects (14 percent). Gastritis was found in 42 subjects (37 percent), of whom 36 (32 percent of the total) were found to be infected with H. pylori on the basis of hematoxylin-eosin staining. H. pylori was not found in any of the 71 subjects with normal histologic features. Gastritis and H. pylori were noted in both the antrum and corpus in 75 percent of those infected (n = 27). The prevalence of H. pylori infection increased from 10 percent (2 of 20 subjects) in those between the ages of 18 and 29, to 47 percent (7 of 15) in those between the ages of 60 and 69, but the effect of age did not reach statistical significance. The prevalence of gastritis increased significantly with advancing age. Stepwise logistic regression analysis revealed that the relative risk for H. pylori infection associated with recent (within six months) antibiotic use was 5.8 (95 percent confidence interval, 1.5 to 22.1), whereas the relative risk was 6.5 (95 percent confidence interval, 1.4 to 29.2) for those who had never used bismuth compounds. We conclude that histologic gastritis and H. pylori infection commonly occur in the stomach of apparently normal persons and increase in prevalence with advancing age. All the subjects with H. pylori infection had gastritis, suggesting a possible etiologic role for the bacterium in the histologic lesion
  551. Dunn BE; Perez-Perez GI; Blaser MJ. "Two-dimensional gel electrophoresis and immunoblotting of Campylobacter pylori proteins". Infection & immunity. 1989 Jun;57(6):1825-1833 (MEDL:2722241 #19274)    

    Whole-cell, outer-membrane protein, flagellum-associated antigens and partially purified urease of Campylobacter pylori were analyzed by two-dimensional gel electrophoresis. C. pylori strains were readily distinguished from strains of Campylobacter jejuni, C. coli, and C. fetus by absence of major outer membrane proteins with Mrs of 41,000 to 45,000. C. pylori strains also lacked the acidic surface-array proteins at Mr 100,000 to 149,000 identified previously in serum-resistant strains of C. fetus. Surface labeling of intact C. pylori cells with 125I revealed two common major proteins, which we have designated protein 2 (pI 5.6 to 5.8, Mr 66,000) and protein 3 (pI 5.2 to 5.5, Mr 63,000). Proteins 2 and 3 were also the major components (subunits) observed in partially purified urease. Partially purified preparations of flagella consistently contained proteins 2 and 3. Thus, urease appears to be associated with both outer membranes and flagella of C. pylori. C. pylori strains also possessed an antigen at Mr 59,000 which was cross-reactive with antiserum against flagella of C. jejuni. However, the antigen did not appear to be associated with flagella per se in C. pylori. Protein 2 was unique to C. pylori among the Campylobacter species studied. It was not recognized by antibody against whole cells of C. jejuni or C. fetus or flagella of C. jejuni. Protein 3 was cross-reactive with antiserum against whole cells of C. jejuni and C. fetus, as were several other major protein antigens. Because protein 2 is a major outer membrane protein that is apparently unique to C. pylori, development of monospecific antibodies against this antigen may be useful for the identification of C. pylori in tissues, and purified antigen may be useful for serologic tests for specific diagnosis of C. pylori infections
  552. Janoff EN; Craft JC; Pickering LK; Novotny T; Blaser MJ; Knisley CV; Reller LB. "Diagnosis of Giardia lamblia infections by detection of parasite-specific antigens". Journal of clinical microbiology. 1989 Mar;27(3):431-435 (MEDL:2715318 #19277)    

    Antigen detection methods may facilitate diagnosis of Giardia lamblia in stool specimens. As determined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis analysis and immunoblotting, G. lamblia cysts and trophozoites share several antigens, especially in the 65-kilodalton and 30- to 34-kilodalton regions. By using blind methods, we compared results obtained by counterimmunoelectrophoresis using cyst-immune rabbit serum and by enzyme-linked immunosorbent assay (ELISA) using trophozoite-immune rabbit serum with results obtained by microscopic examination of a preserved, concentrated, and permanently stained stool specimen. Results were similar when these three methods were used to examine 118 stool specimens from clinical microbiology laboratories (53 specimens with G. lamblia) and specimens from 239 day-care-center toddlers (39 specimens with G. lamblia). Compared with microscopy, we found, for counterimmunoelectrophoresis and ELISA, respectively: sensitivity, 88 versus 94%; specificity, 97 versus 95%; positive predictive value, 86 versus 76%; negative predictive value, 98 versus 97%; and concordance, 89%. The false-positive rate by ELISA was 24% (10 of 42) in day-care-center toddlers but only 3% (1 of 32) in healthy adults (P less than 0.04) as corroborated by microscopy. This discrepancy suggests that the ELISA may be more sensitive than microscopy, which is considered the reference standard, and that results may be dependent, in part, on the epidemiology of the infection in the study subjects
  553. Kobayashi K; Blaser MJ; Brown WR. "Identification of a unique IgG Fc binding site in human intestinal epithelium". Journal of immunology. 1989 Oct 15;143(8):2567-2574 (MEDL:2529312 #19272)    

    In experiments to determine whether serum antibodies in patients with Crohn's disease could be used as probes for detecting potentially etiologic Ag in the patients' tissues, we found that peroxidase (HRP)-labeled IgG from healthy persons, as well as from the patients, bound to normal colonic and small intestinal epithelium, mostly or entirely to goblet cells. The binding was due to a reaction involving the Fc region of IgG because HRP-labeled Fc fragments of IgG bound, but HRP-Fab, HRP-IgA, and HRP-bovine albumin did not, and because binding of HRP-IgG was inhibited competitively by unlabeled IgG or Fc fragments but not by IgG Fab fragments or IgA. These immunohistochemical results were confirmed by ELISA with microtiter wells coated with a sonicated homogenate from human colonocytes. The epithelial IgG Fc binding site was characterized by SDS-PAGE as consisting of a high Mr (greater than 200,000 Da) and a 78,000-Da component. It bound all four subclasses of human IgG and bound aggregated as well as monomeric IgG. It is distinct from known human Fc-gamma R by lack of recognition by mAb to those receptors and differences in affinity for various subclasses of human and murine IgG. This unique IgG Fc binding site might be involved in immunologic defense of the gut, perhaps by mediating reactions between foreign Ag and the contents of goblet cells
  554. Kobayashi K; Blaser MJ; Brown WR. "Immunohistochemical examination for mycobacteria in intestinal tissues from patients with Crohn's disease". Gastroenterology. 1989 Apr;96(4):1009-1015 (MEDL:2647572 #19276)    

    We conducted an immunohistochemical search for mycobacteria in the intestinal tissues of patients with Crohn's disease. Tissues obtained by biopsy or surgical resection and fixed by a variety of methods (formalin, periodate-lysine-paraformaldehyde, fresh-frozen) were reacted by an immunoperoxidase method with antibodies to (a) Mycobacterium paratuberculosis strain linda, (b) M. tuberculosis, and (c) the common mycobacterial antigen, lipoarabinomannan. Each of the antibody preparations was shown capable of detecting a variety of typical and atypical mycobacteria (M. tuberculosis, M. kansasii, M. fortuitum, M. chelonei, M. paratuberculosis, and cell wall-defective as well as cell wall-intact forms of M. avium intracellulare) under conditions identical to those used for staining the patients' tissues. We did not detect mycobacteria in any of the 67 specimens from 30 patients examined. These results, in conjunction with those of our previous serologic studies, do not support the hypothesis that infection with a Mycobacterium causes Crohn's disease
  555. Perez-Perez GI; Cohn DL; Guerrant RL; Patton CM; Reller LB; Blaser MJ. "Clinical and immunologic significance of cholera-like toxin and cytotoxin production by Campylobacter species in patients with acute inflammatory diarrhea in the USA". Journal of infectious diseases. 1989 Sep;160(3):460-468 (MEDL:2760498 #19273)       

    The humoral immune response to both Campylobacter jejuni cell surface antigens and to potential toxins of the organism was studied in 64 adults with inflammatory diarrhea. In an enzyme-linked immunosorbent assay (ELISA) for surface antigens, 17 (71%) of 24 persons with Campylobacter enteritis showed seroconversion in more than one immunoglobulin class, versus only 2 (5%) of 40 patients with non-Campylobacter enteritis. In a GM1, ganglioside-based ELISA for detecting serum IgG to cholera-like enterotoxin, only one patient studied showed seroconversion to the enterotoxin. Of 22 Campylobacter isolates studied for production of cholera-like toxin, none of the supernatants from the Campylobacter strains were positive. Supernatants were also tested for enterotoxin and cytotoxic activity on Chinese hamster ovary cells; all isolates were negative for enterotoxin activity. In contrast, cytotoxin was produced by 7 (32%) isolates but was usually low-level and was not neutralized by patient's serum. These findings indicate that production of cholera-like toxin and cytotoxin by Campylobacter strains in the United States occurs in few strains and that host immune response is absent; their biologic significance in the pathogenesis of Campylobacter infections remains unclear
  556. Russell RG; Blaser MJ; Sarmiento JI; Fox J. "Experimental Campylobacter jejuni infection in Macaca nemestrina". Infection & immunity. 1989 May;57(5):1438-1444 (MEDL:2707853 #19275)    

    Experimental infection of four specific-pathogen-free Macaca nemestrina monkeys (aged 3.5 and 4.5 months) with Campylobacter jejuni 81-176 caused acute diarrheal illness, characterized by fluid diarrhea, bloody stools, and fecal leukocytes, which lasted for approximately 7 to 11 days. Histologic examination of intestinal biopsies showed acute colitis characterized by infiltration of the mucosa with neutrophils and lymphocytes, and cryptitis. There were no histologic changes in the small intestine. Excretion of C. jejuni was demonstrated for 2 to 4 weeks postchallenge. Plasma antibodies to C. jejuni group antigen were elevated after challenge. Only mild diarrhea occurred after rechallenge with the same strain or with a heterologous C. jejuni strain (79-168) followed by further elevation in specific immunoglobulins A, M, and G. Four 1-year-old juvenile M. nemestrina monkeys which had experienced multiple infections with Campylobacter spp. did not exhibit illness when challenged with C. jejuni 81-176. All had elevated immunoglobulin A, M, and G plasma antibodies prior to challenge, and these humoral antibody levels were indicative of the immunity to challenge. The results demonstrate that C. jejuni infection in M. nemestrina caused colitis with clinical and pathologic results similar to those found in humans and indicate that prior infection protects against subsequent challenge
  557. Black RE; Levine MM; Clements ML; Hughes TP; Blaser MJ. "Experimental Campylobacter jejuni infection in humans". Journal of infectious diseases. 1988 Mar;157(3):472-479 (MEDL:3343522 #19292)       

    Two strains of Campylobacter jejuni ingested by 111 adult volunteers, in doses ranging from 8 x 10(2) to 2 x 10(9) organisms, caused diarrheal illnesses. Rates of infection increased with dose, but development of illness did not show a clear dose relation. Resulting illnesses with strain A3249 ranged from a few loose stools to dysentery, with an average of five diarrheal stools and a volume of 509 mL. Infection with strain 81-176 was more likely to cause illness, and these illnesses were more severe, with an average of 15 stools and 1484 mL of total stool volume. All patients had fecal leukocytes. The dysenteric nature of the illness indicates that the pathogenesis of C. jejuni infection includes tissue inflammation. Ill volunteers developed a serum antibody response to the C. jejuni group antigen and were protected from subsequent illness but not infection with the same strain
  558. Black, Robert E; Levine, Myron M; Clements, Mary L; Hughes, Timothy P; Blaser, Martin J. Experimental Campylobacter Jejuni Infection in Humans. [S.l.] : Ft. Belvoir Defense Technical Information Center, 1988. 9 p..   

    Two strains of Campylobacter jejuni ingested by 111 adult volunteers, in doses ranging from 8 x 102 to 2 x 109 organisms, caused diarrheal illnesses. Rates of infection increased with dose, but development of illness did not show a clear dose relation. Resulting illnesses with strain A3249 ranged from a few loose stools to dysentery, with an average of five diarrheal stools and a volume of 509 mL. Infection with strain 81-176 was more likely to cause illness, and these illnesses were more severe, with an average of 15 stools and 1484 mL of total stool volume. All patients had fecal leukocytes. The dysenteric nature of the illnesses indicates that the pathogenesis of C. jejuni infection includes tissue inflammation. Ill volunteers developed a serum antibody response to the C. jejuni group antigen and were protected from subsequent illness but not infection with the same strain
  559. Blaser MJ. "Type B gastritis, aging, and Campylobacter pylori". Archives of internal medicine. 1988 May;148(5):1021-1022 (MEDL:3365072 #19288)       
  560. Blaser MJ; Smith PF; Repine JE; Joiner KA. "Pathogenesis of Campylobacter fetus infections. Failure of encapsulated Campylobacter fetus to bind C3b explains serum and phagocytosis resistance". Journal of clinical investigation. 1988 May;81(5):1434-1444 (MEDL:3366901 #19287)       

    Campylobacter fetus ssp. fetus strains causing systemic infections in humans are highly resistant to normal and immune serum, which is due to the presence of high molecular weight (100,000, 127,000, or 149,000) surface (S-layer) proteins. Using serum-resistant parental strains (82-40 LP and 23D) containing the 100,000-mol wt protein and serum-sensitive mutants (82-40 HP and 23B) differing only in that they lack the 100,000-mol wt protein capsule, we examined complement binding and activation, and opsono-phagocytosis by polymorphonuclear leukocytes. C3 consumption was similar for all four strains but C3 was not efficiently bound to 82-40 LP or 23D even in the presence of immune serum, and the small amount of C3 bound was predominently the hemolytically inactive iC3b fragment. Consumption and binding of C5 and C9 was significantly greater for the unencapsulated than the encapsulated strains. Opsonization of 82-40 HP with heat-inactivated normal human serum caused greater than 99% killing by human PMN. Similar opsonization of 82-40 LP showed no kill, but use of immune serum restored killing. Findings in a PMN chemiluminescence assay showed parallel results. Association of 32P-labeled 82-40 HP with PMN in the presence of HINHS was 19-fold that for the 82-40 LP, and electron microscopy illustrated that the difference was in uptake rather than in binding. These results indicate that presence of the 100,000-mol wt protein capsule on the surface of C. fetus leads to impaired C3b binding, thus explaining serum resistance and defective opsonization in NHS, mechanisms that explain the capacity of this enteric organism to cause systemic infections
  561. Chalker RB; Blaser MJ. "A review of human salmonellosis: III. Magnitude of Salmonella infection in the United States". Reviews of infectious diseases. 1988 Jan-Feb;10(1):111-124 (MEDL:2832925 #19293)    

    National surveillance for salmonella infections was established in 1962, following recognition of the importance of Salmonella organisms as the cause of potentially preventable infectious disease in the United States. Reports of infections due to Salmonella have risen progressively to approximately 40,000 per year. In contrast, the parallel reporting system for infections due to Shigella shows no such increase. Because a passive surveillance system is used, it has been assumed salmonella infections have been substantially underreported. Three independent methods-determination of carriage rates, calculation of sequential surveillance artifacts, and calculation of overall surveillance artifact-were used to estimate the annual number of salmonella infections in the United States; the results were compared with those of a previous study. These methods produced estimates ranging from 800,000 to 3,700,000 (mean = 1,900,000; median = 1,400,000) infections annually. Accurate assessment of the number of infections is important for determining complication rates and for evaluating the efficacy of control programs
  562. Janoff EN; Douglas JM; Gabriel M; Blaser MJ; Davidson AJ; Cohn DL; Judson FN. "Class-specific antibody response to pneumococcal capsular polysaccharides in men infected with human immunodeficiency virus type 1". Journal of infectious diseases. 1988 Nov;158(5):983-990 (MEDL:3183430 #19281)       

    We characterized the effect of infection with human immunodeficiency virus type 1 (HIV) on levels of total immunoglobulins and pneumococcal vaccine-specific immunoglobulins in 28 heterosexual and 25 homosexual men seronegative for HIV; 27 asymptomatic, seropositive homosexual men; and 21 patients with AIDS. Total serum IgG levels were increased in both HIV-seropositive groups compared with the HIV-seronegative men (P less than .001). Total IgM levels, however, were elevated only in the asymptomatic, HIV-seropositive men (P less than .08); total IgA levels were elevated only in the patients with AIDS (P less than .05). Vaccine-specific serum IgG, IgM, and IgA significantly increased over baseline three and six weeks after immunization in all groups (P less than .05). Responses to vaccine among the HIV-seronegative groups were similar but were greater for all antibody classes than were responses among the HIV-seropositive groups (P less than .05)
  563. Janoff EN; Smith PD; Blaser MJ. "Acute antibody responses to Giardia lamblia are depressed in patients with AIDS". Journal of infectious diseases. 1988 Apr;157(4):798-804 (MEDL:3346571 #19290)       

    We investigated the ability of patients with AIDS to develop antibody responses to a naturally encountered antigenic stimulus, Giardia lamblia. Using an enzyme-linked immunosorbent assay to detect IgG, IgM, and IgA to G. lamblia trophozoites, we tested sera from 29 patients with AIDS (15 without and 14 with G. lamblia infection); 20 healthy homosexual men; and 91 immunocompetent heterosexual subjects, 25 of whom were infected with G. lamblia. Heterosexual subjects infected with G. lamblia had significantly higher levels of all three classes of specific antibody than did the uninfected subjects (P less than .0001). Patients with AIDS who had acute symptomatic giardiasis had significantly lower levels of all antibodies than did the heterosexual subjects who had giardiasis; specific IgM was absent in all but one patient with AIDS. The symptomatically infected patients with AIDS had low levels of G. lamblia-specific antibodies that were similar to those of the uninfected patients with AIDS. Patients with AIDS do not have to suffer from prolonged symptomatic G. lamblia infections, however, because available therapy is effective against the parasite, independent of a patient's immune status
  564. Kobayashi K; Brown WR; Brennan PJ; Blaser MJ. "Serum antibodies to mycobacterial antigens in active Crohn's disease". Gastroenterology. 1988 Jun;94(6):1404-1411 (MEDL:2452116 #19284)    

    Infection with a species of Mycobacterium has been implicated in the pathogenesis of Crohn's disease. Therefore, we attempted to determine whether a specific serum antibody response to mycobacteria occurs in patients with the disease. We tested sera of patients with active Crohn's disease and several control groups in an enzyme-linked immunosorbent assay for reactivity with two mycobacterial antigens: (a) lipoarabinomannan, a highly immunogenic somatic lipopolysaccharide present in the cell walls of all species of the Mycobacterium genus, and (b) a protoplasmic antigenic preparation from M. sp strain linda, the mycobacterium that has been specifically implicated in Crohn's disease. We found no significant elevation in immunoglobulin A, immunoglobulin G, or immunoglobulin M antibody levels to these two antigen preparations in the Crohn's disease patients. Moreover, no subset of patients (sex, age, Crohn's disease activity index, location of disease, duration of disease, operations, or response to treatment) had elevated antibody levels. As virtually all known chronic infectious diseases have an associated serologic response to the etiologic agent, our findings greatly diminish the likelihood that Crohn's disease is caused by an infection with a mycobacterium
  565. Moore MA; Blaser MJ; Perez-Perez GI; O'Brien AD. "Production of a Shiga-like cytotoxin by Campylobacter". Microbial pathogenesis. 1988 Jun;4(6):455-462 (MEDL:3193876 #19283)       

    Cell lysates and culture supernatants of 36 Campylobacter isolates from patients with enteritis were tested for cytotoxic activity on HeLa cells. Cytotoxic activity was considered Shiga-like if neutralized by monoclonal antibody to the B subunit of Shiga-like toxin I of Escherichia coli and rabbit anti-Shiga toxin. Fifteen of the Campylobacter isolates produced no detectable cytotoxin, 10 produced a non-neutralizable cytotoxin, and 11 produced low levels of a cell-associated SLT. However, under low stringency conditions no hybridization was observed between a DNA fragment containing cloned SLT-I genes and restriction enzyme-digested total DNA from a Campylobacter strain that produced low levels of a Shiga-like toxin I. The Shiga-like toxin neutralizing titers in sera from 15 patients with C. jejuni infections, 5 patients infected with S. sonnei, and 20 healthy persons were then determined. No rise in neutralizing titer between acute and convalescent sera of patients with C. jejuni infection or S. sonnei infection was observed, although 27% of C. jejuni-infected patients, 40% of S. sonnei-infected patients, and 30% of the healthy controls had neutralizing activity in their sera. These data indicate that low levels of Shiga-like toxin are produced by some Campylobacter isolates but that SLT is genetically distinct from the SLT-I toxin produced at high levels by certain E. coli. The findings also suggest that exposure to SLTs is common in the adult population but not as a consequence of infection with C. jejuni or S. sonnei
  566. Pei Z; Ellison RT; Lewis RV; Blaser MJ. "Purification and characterization of a family of high molecular weight surface-array proteins from Campylobacter fetus". Journal of biological chemistry. 1988 May 5;263(13):6416-6420 (MEDL:3360785 #19285)    

    A variety of Gram-negative and Gram-positive bacteria possess crystalline surface layers, although little is known of their function. We previously have shown that the high molecular weight surface-array proteins of Campylobacter fetus are important in both the pathogenicity and antigenicity of this organism. For biochemical and immunological characterization, we purified high molecular weight (100,000, 127,000, 149,000) surface-array proteins from three C. fetus strains using sequential gel filtration and ion exchange high performance liquid chromatography. These proteins are acidic with pI values between 4.12 and 4.25 and contain large proportions of acidic amino acids (19.7%-22.0%) in addition to hydrophobic amino acids (37.3%-38.5%). They share a novel amino-terminal sequence through at least 19 residues. Carbohydrate analysis using periodic acid-Schiff staining and treatment with trifluoromethanesulfonic acid shows no evidence of glycosylation. Antiserum to a purified Mr = 100,000 protein from C. fetus 82-40 LP cross-reacts with three other purified C. fetus surface-array proteins by enzyme-linked immunosorbent assay with titers greater than 12,800. We conclude that: 1) there is a family of surface-array proteins of C. fetus with common structural and antigenic characteristics; 2) that these molecules have similar biochemical characteristics to surface-array proteins described for other bacteria; but however, 3) by amino-terminal sequence analysis these are unique
  567. Pei Z; Ellison, Richart T II; Lewis, Randolph V; Blaser, Martin J. Purification and Characterization of a Family of High Molecular Weight Surface-Array Proteins from Campylobacter Fetus. [S.l.] : Ft. Belvoir Defense Technical Information Center, 1988. 6 p..   

    A variety of Gram-negative and Gram-positive bacteria possess crystalline surface layers, although little is known of their function. We previously have shown that the high molecular weight surface-array proteins of Campylobacter fetus are important in both the pathogenicity and antigenicity of this organism. For biochemical and immunological characterization, we purified high molecular weight(100,000, 127,000, 149,000) surface-array proteins from three C. fetus strains using sequential gel filtration and ion exchange high performanc liquid chromatography. These proteins are acidic with pl values between 4.12 and 4.25 and contain large proportions of acidic amino acids (19. 7%-22.0%) in addition to hydrophobic amino acids (37.3%-38.5%). They share a novel amino-terminal sequence through at least 19 residues
  568. Perez-Perez GI; Dworkin BM; Chodos JE; Blaser MJ. "Campylobacter pylori antibodies in humans". Annals of internal medicine. 1988 Jul 1;109(1):11-17 (MEDL:3288028 #19282)    

    STUDY OBJECTIVE: To determine the diagnostic value of assays to measure serum antibodies to Campylobacter pylori, and to use these assays to determine the prevalence of C. pylori infection in a healthy population. DESIGN: A survey of patients having endoscopies for upper gastrointestinal symptoms, patients with other gastrointestinal illnesses, and healthy controls. SETTING: Outpatients attending endoscopy suites in two university-affiliated medical centers. PATIENTS: One hundred and twenty patients who had gastroduodenoscopies, 61 patients with lower intestinal illnesses, and 166 healthy controls. INTERVENTION: Assay to detect serum IgA, IgG, and IgM antibodies specific for C. pylori. MEASUREMENTS AND MAIN RESULTS: Absorption with other gram-negative pathogens showed that IgG and IgA assays, but not IgM assays, were specific for C. pylori. In patients in whom C. pylori had been isolated and who had gastritis diagnosed by histologic methods, significantly higher mean IgA and IgG levels were seen compared with patients without demonstrable C. pylori or gastritis. The sensitivity and specificity of a positive value in both IgA and IgG assays were more than 93%. Among healthy persons, IgG and IgA antibodies were rarely seen in patients less than 20 years old, but antibody prevalence progressed with age, reaching 50% in patients more than 60 years old. High IgA and IgG levels to C. pylori in five persons tested remained stable for more than 1 year, suggesting the organism persists for at least that period. In 61 patients with acute bacterial enteritis, acute pancreatitis, Crohn disease, or ulcerative colitis, prevalence of antibodies to C. pylori was consistent with age and unrelated to current disease. CONCLUSIONS: Campylobacter pylori infection, which is highly associated with active gastritis, may be diagnosed by serologic assay. Acquisition of infection begins in adult life, and prevalence increases with age
  569. Perlman DM; Ampel NM; Schifman RB; Cohn DL; Patton CM; Aguirre ML; Wang WL; Blaser MJ. "Persistent Campylobacter jejuni infections in patients infected with the human immunodeficiency virus (HIV)". Annals of internal medicine. 1988 Apr;108(4):540-546 (MEDL:3348562 #19289)    

    We identified Campylobacter jejuni infections in four patients infected with the human immunodeficiency virus (HIV); three had persistent and severe C. jejuni infections. Multiple isolates obtained from each patient had the same biochemical and serotypic characteristics, indicating recurrent infection rather than reinfection with unrelated strains. Serum antibody responses to C. jejuni group antigens by enzyme-linked immunosorbent assay were markedly impaired in the three patients with persistent infection compared with forty-two immunocompetent C. jejuni-infected controls and with the HIV-infected patient who readily cleared the organism. One patient was bacteremic; his blood isolate was killed by normal serum but was resistant to his own serum, whereas a simultaneous stool isolate of a different serotype was sensitive. Failure of two patients to eradicate the organism and long-term administration of erythromycin therapy led to the in-vivo development of resistance to this antibiotic, which is most frequently used to treat C. jejuni infections
  570. Stout JE; Joly J; Para M; Plouffe J; Ciesielski C; Blaser MJ; Yu VL. "Comparison of molecular methods for subtyping patients and epidemiologically linked environmental isolates of Legionella pneumophila". Journal of infectious diseases. 1988 Mar;157(3):486-495 (MEDL:3343523 #19291)       

    We used the molecular techniques of monoclonal antibody typing, plasmid analysis, and outer membrane protein profiling to subtype 159 patients' and environmental (water distribution system) isolates of Legionella pneumophila serogroup 1 from 18 institutions. The ability of these techniques to match patients' and epidemiologically linked environmental isolates from outbreaks of Legionnaires' disease at seven institutions was also compared. Two different panels of monoclonal antibodies (I and II) identified nine subtypes (one new disease-causing subtype) and six subtypes, respectively. The Bellingham 1 subtype type was the most common among environmental isolates, and the Philadelphia 1 subtype predominated among patients' isolates from all institutions except the Veterans Administration Medical Center in Pittsburgh, Pennsylvania. The source of an isolate (patient vs. environment) and its monoclonal antibody subtype were significantly associated (P less than .01). With use of the molecular techniques tested, the subtypes of patients' isolates were identical to those of epidemiologically linked environmental isolates from the same hospital
  571. Taylor DN; Echeverria P; Pitarangsi C; Seriwatana J; Bodhidatta L; Blaser MJ. "Influence of strain characteristics and immunity on the epidemiology of Campylobacter infections in Thailand". Journal of clinical microbiology. 1988 May;26(5):863-868 (MEDL:3384911 #19286)    

    To determine how strain differences and immunity affect the clinical expression of Campylobacter infections, we conducted a study of acute diarrheal disease in Thailand in which specimens from children with Campylobacter infections were cultured weekly for up to 12 weeks to determine the serotype-specific length of time of convalescent-phase excretion and rate of reinfection. Levels of immunoglobulin G to cell-surface antigens of C. jejuni were determined in another population of healthy children who were closely related by age and location to the children in the diarrheal disease study. Campylobacter species were initially isolated from 18% of 586 children under 5 years old with diarrhea; most isolates in Thailand belonged to serotypes commonly found in developed countries. C. coli was significantly less often associated with symptomatic infections and with bloody diarrhea than C. jejuni (P less than 0.001 and P = 0.045, respectively). The peak age of isolation and the peak level of immunoglobulin G to Campylobacter species occurred before 2 years of age. The mean duration of convalescent-phase excretion was 14 +/- 2 (standard error of the mean) days for children less than 1 year old and 8 +/- 2 days for children 1 to 5 years old (P = 0.02, t test). Infection with another Campylobacter serotype was found in 34% of 105 children during the 12-week follow-up period. The rate of reinfection in these children was 15% (range, 8 to 22%) each week.(ABSTRACT TRUNCATED AT 250 WORDS)
  572. Blaser MJ. "Gastric Campylobacter-like organisms, gastritis, and peptic ulcer disease". Gastroenterology. 1987 Aug;93(2):371-383 (MEDL:3297911 #19294)    

    Although the presence of gastric bacteria has been long established, the recognition and isolation of Campylobacter pylori and similar organisms has opened a new era in the understanding of inflammatory gastroduodenal conditions. Visualization or isolation of gastric Campylobacter-like organisms (GCLOs) is significantly associated with histologic evidence of gastritis, especially of the antrum. Correlation with peptic ulceration also exists but probably is due to concurrent antral gastritis. Outbreaks of hypochlorhydria with concomitant gastritis have been attributed to GCLO infection, and a human volunteer became ill after ingesting C. pylori. Despite rapid microbiologic characterization of the organisms and the epidemiology, pathology, and serology of infection, the pathogenetic significance of GCLOs remains unknown. Whether GCLOs cause, colonize, or worsen gastritis must be considered an unanswered question at present. The efficacy of antimicrobial treatment of GCLO infection on the natural history of gastritis is not presently resolved. Nevertheless, GCLOs are at the least an important marker of inflammatory gastroduodenal disease, and attempts to ascertain their clinical significance are clearly warranted
  573. Blaser MJ. "Isolation of the human immunodeficiency virus from cervical secretions during menses [Letter]". Annals of internal medicine. 1987 Jun;106(6):912-912 (MEDL:3646868 #19296)    
  574. Blaser MJ; Sazie E; Williams LP. "The influence of immunity on raw milk--associated Campylobacter infection". JAMA. 1987 Jan 2;257(1):43-46 (MEDL:2431167 #19300)       

    After a retreat to an Oregon farm, 19 of 31 college students developed an acute gastrointestinal illness. Campylobacter jejuni infection was recognized in all the ill students and caused asymptomatic infections in three others. In total, 22 (88%) of 25 students who consumed raw milk for the first time became infected as compared with none of two who had not consumed raw milk. Among ten persons who chronically consumed raw milk, none was ill, a striking difference from the 76% attack rate among the 25 acutely exposed students. The quantity of raw milk consumed was directly related to the occurrence and severity of illness. Acutely infected students showed significant rises in C jejuni-specific immunoglobulins, whereas the low antibody levels seen in unexposed persons did not rise. In contrast, acute-phase serum samples from persons with chronic exposure to raw milk showed elevated antibody levels to C jejuni. These findings indicate that chronic raw milk consumption is associated with elevated levels of C jejuni-specific serum antibodies and with immunity to symptomatic infection
  575. Blaser MJ; Smith PF; Hopkins JA; Heinzer I; Bryner JH; Wang WL. "Pathogenesis of Campylobacter fetus infections: serum resistance associated with high-molecular-weight surface proteins". Journal of infectious diseases. 1987 Apr;155(4):696-706 (MEDL:3819475 #19298)       

    Campylobacter fetus subspecies fetus causes both systemic and diarrheal illnesses. We studied 38 strains of C. fetus isolated from 34 patients; underlying illness was present in eight (89%) of nine patients with only systemic isolates compared with three (20%) of 15 patients with only fecal isolates (P = .002). In a standardized assay of susceptibility to normal human serum, 27 (71%) strains were resistant, six (16%) had intermediate susceptibility, and five (13%) were serum sensitive. Major protein bands migrating at 100 kDa or 125 kDa on polyacrylamide gels were present in all of the 25 serum-resistant strains tested but in only four of seven serum-sensitive isolates of C. fetus from humans and animals (P = .007). The presence of these bands was associated with type A lipopolysaccharide. A low-passaged strain, 82-40, was serum resistant and contained the 100-kDa protein; however, a spontaneous mutant of this strain lacked this band and was serum sensitive. The 100-kDa and 125-kDa proteins of three strains of C. fetus were antigenically cross reactive or identical and were exposed on the surface of the C. fetus cell. Serum resistance is inherent to most C. fetus isolates from humans and is associated with the presence of cross-reactive surface proteins
  576. Blaser, Martin J; Smith, Paul F; Hopkins, Janet A; Heinzer, Ivo; Bryner, John H. Pathogenesis of Campylobacter Fetus Infections: Serum Resistance Associated with High-Molecular-Weight Surface Proteins. [S.l.] : Ft. Belvoir Defense Technical Information Center, 1987. 12 p..

    Campylobacter fetus subspecies fetus causes both systemic and diarrheal illnesses. We studied 38 strains of C. fetus isolated from 34 patients; underlying illness was present in eight (89%) of nine patients with only systemic isolates compared with three (20%) of 15 patients with only fecal isolates (P = .002). In a standardized assay of susceptibility to normal human serum, 27 (71%) strains were resistant, six (16%) had intermediate susceptibility, and five (13%) were serum sensitive. Major protein bands migrating a 100 kDa or 125 kDa on polyacrylamide gels were present in all of the 25 serum-resistant strains tested but in only four of seven serum-sensitive isolates of C fetus from humans and animals (P = .007). The presence of these bands was associated with type A lipopolysaccharide. A low-passaged strain, 82- 40, was serum resistant and contained the 100-kDa protein; however, a spontaneous mutant of this strain lacked this band and was serum sensitive. The 100-kDa and 125-kDa proteins of three strains of C fetus were antigenically cross reactive or identical and were exposed on the surface of the C fetus cell. Serum resistance is inherent to most C. fetus isolates from humans and is associated with the presence of cross-reactive surface proteins
  577. Dunn BE; Blaser MJ; Snyder EL. "Two-dimensional gel electrophoresis and immunoblotting of Campylobacter outer membrane proteins". Infection & immunity. 1987 Jul;55(7):1564-1572 (MEDL:3298060 #19295)    

    We characterized outer membrane proteins (OMPs) from selected Campylobacter jejuni, C. coli, and C. fetus strains by two-dimensional gel electrophoresis (2DGE), using isoelectric focusing and sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE), and by immunoblotting with immune rabbit serum. The flagellar band with a molecular mass of 63 kilodaltons (kDa) demonstrated previously by one-dimensional SDS-PAGE was shown by 2DGE to consist of one or several charge trains, depending upon the species, strain, and type of preparation studied; each of the individual peptides was found to be antigenic by immunoblotting. In contrast, in all of the strains studied, the major OMP (43 to 44 kDa) of C.jejuni and C. coli consisted of a single isomeric form which was weakly immunogenic. Several minor proteins (29 to 31 kDa) were found to be strongly immunogenic by immunoblotting. C. fetus strains possessed two major OMPs of 45 to 47 kDa, each of which consisted of either a single isomer or a major isomer comprising at least 90% of the major OMP. Serum-resistant strains of C. fetus possessed an acid-labile 100-kDa glycoprotein (pI, 4.1) which was markedly diminished or absent in serum-sensitive strains. These 2DGE analyses provide information that is useful in taxonomic and epidemiologic studies and for the purification of surface antigens for the development of campylobacter vaccines and may also facilitate the identification of specific virulence factors
  578. Dunn, Bruce E; Blaser, Martin J; Snyder, Edward L. Two-Dimensional Gel Electrophoresis and Immunoblotting of Campylobacter Outer Membrane Proteins. [S.l.] : Ft. Belvoir Defense Technical Information Center, 1987. 10 p..   

    We characterized outer membrane proteins (OMPs) from selected Campylobacter jejuni. C. coli, and C. fetus strains by two-dimensional gel electrophoresis (2DGE), using isoelectric focusing and sodium dodecyl sulfate- polyacrylamide gel electrophoresis (SDS-PAGE), and by immunoblotting with immune rabbit serum. The flagellar band with a molecular mass of 63 kilodaltons (kDa) demonstrated previously by one-dimensional SDS-PAGE was shown by 2DGE to consist of one or several charge trains, depending upon the species, strain, and type of preparation studied: each of the individual peptides was found to be antigenic by immunoblotting. In contrast, in all of the strains studied, the major OMP (43 to 44 kDa) of C. jejuni and C. coli consisted of a single isomeric form which was weakly immunogenic. Several minor proteins (29 to 31 kDa) were found to be strongly immunogenic by immunoblotting. C. fetus strains possessed two major OMPs of 45 to 47 kDa, each of which consisted of either a single isomer or a major isomer comprising at least 90% of the major OMP. Serum-resistant strains of C. fetus possessed an acid-labile 100-kDa glycoprotein (pI. 4.1) which was markedly diminished or absent in serum-sensitive strains. These 2DGE analyses provide information that is useful in taxonomic and epidemiologic studies and for the purification of surface antigens for the development of campylobacter vaccines and may also facilitate the identification of specific virulence factors
  579. Perez-Perez GI; Blaser MJ. "Conservation and diversity of Campylobacter pyloridis major antigens". Infection & immunity. 1987 May;55(5):1256-1263 (MEDL:3552997 #19297)    

    Infection with Campylobacter pyloridis has been strongly associated with gastritis in humans although its etiologic significance is currently undefined. We examined the structure and antigenicity of whole-cell, outer-membrane, acid-extractable surface protein, and proteinase K-treated whole cell lysate preparations from eight C. pyloridis strains by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and immunoblotting with homologous and heterologous immune rabbit serum. Whole-cell and outer-membrane profiles observed in all strains of C. pyloridis were nearly identical; none were similar to those of C. jejuni and C. fetus. Major whole-cell bands migrated at 26,000, 29,000, 56,000, and 62,000 molecular weights. The acid-extracted protein profiles of all C. pyloridis strains also were similar to one another and showed similarities with acid-extracted proteins from C. jejuni, with major bands migrating at 29,000, 48,000 to 53,000, and 62,000. All proteinase K-treated lysates showed different lipopolysaccharide (LPS) profiles, ranging from rough to smooth with multiple repeating side chains. Immunoblots of whole-cell and proteinase K-treated preparations of the C. pyloridis strains showed that there was antigenic cross-reactivity of proteins migrating at 62,000 and 56,000, but not in other regions, and cross-reactivity between LPS core regions but not side chains. These results suggest that C. pyloridis has both protein and core LPS group antigens and strain-specific protein and LPS side chain antigens
  580. Taylor DN; Blaser MJ; Echeverria P; Pitarangsi C; Bodhidatta L; Wang WL. "Erythromycin-resistant Campylobacter infections in Thailand". Antimicrobial agents & chemotherapy. 1987 Mar;31(3):438-442 (MEDL:3579261 #19299)       

    Erythromycin therapy was compared with no treatment in a prospective trial of acute diarrheal disease among 100 infants in an orphanage in Bangkok. Within 24 h of the onset of diarrhea, 50 children received erythromycin ethylsuccinate (40 mg/kg per day) in four divided doses for 5 days. Campylobacter jejuni isolated from 31, Campylobacter coli isolated from 21, and Shigella spp. isolated from 21 of 100 children were the most commonly recognized pathogens; use of a sensitive, nonselective method substantially increased Campylobacter isolation. Treatment with erythromycin had no effect on the duration of diarrhea caused by Campylobacter spp., Shigella spp., or other agents; 37% of the treatment group and 35% of the control group had diarrhea for 1 week. Of 23 Campylobacter strains isolated from the treatment group before treatment, 15 (65%) were resistant (MIC, greater than or equal to 8 micrograms/ml) to erythromycin. Among orphanage-acquired strains, 53% of 43 C. jejuni strains and 91% of 23 C. coli strains were resistant to erythromycin compared with 11% of 114 C. jejuni strains and 46% of 35 C. coli strains that were community acquired. Erythromycin resistance is common among Campylobacter strains in Bangkok, especially in an institutional setting, which may account for the lack of efficacy of erythromycin for treatment of acute diarrheal illnesses
  581. Taylor, David N; Blaser, Martin J; Echeverria, Peter; Pitarangsi, Chittima; Bodhidatta, Ladaporn. Erythromycin-resistant campylobacter infections in Thailand. [S.l.] : Ft. Belvoir Defense Technical Information Center, 1987. 6 p. .

    Erythromycin therapy was compared with no treatment in a prospective trial of acute diarrheal disease among 100 infants in an orphanage in Bangkok. Within 24 h of the onset of diarrhea, 50 children received erythromycin ethylsuccinate (40 mg/kg per day) in four divided doses for 5 days. Campylobacter jejuni isolated from 31, Campylobacter coli isolated from 21, and Shigella spp. isolated from 21 of 100 children were the most commonly recognized pathogens; use of a sensitive, nonselective method substantially increased Campylobacter isolation. Treatment with erythromycin had no effect on the duration of diarrhea caused by Campylobacter spp., Shigella spp., or other agents; 37% of the treatment group and 35% of the control group had diarrhea for 1 week. Of 23 Campylobacter strains isolated from the treatment group before treatment, 15 (65%) were resistant (MIC, > or = 8 micrograms/ml) to erythromycin. Among orphanage-acquired strains, 53% of 43 C. jejuni strains and 91% of 23 C. coli strains were resistant to erythromycin compared with 11% of 114 C. jejuni strains and 46% of 35 C. coli strains that were community acquired. Erythromycin resistance is common among Campylobacter strains in Bangkok, especially in an institutional setting, which may account for the lack of efficacy of erythromycin for treatment of acute diarrheal illnesses
  582. Wang, Wen-Lang; Blaser, Martin J. Detection of Pathogenic Campylobacter Species in Blood Culture Systems. [S.l.] : Ft. Belvoir Defense Technical Information Center, 1987. 12 p..   

    ecause differences in recognition of Campylobacter fetus and Campylobacter jejuni in systemic infectious may be due partially to differences in the ability to cultivate these organisms, we studied their growth characteristics in two widely used blood culture systems. In the Roche Septi- chek system over a broad range of inocula all strains were detected in broth within 2 days and on paddles within 3 days. In the BACTEC 6 B aerobic bottles C. jejuni and C. fetus took a median of 5 and 3 days, respectively, to reach a median of 2 days to reach the growth index threshold. However, in the BACTEC 7 D anaerobic bottles, C. fetus required a median of 2 days to reach growth index threshold, whereas for C. jejuni the median was greater than 10 days. The poor performance of C. jejuni in both BACTEC systems may have been due to unfavorable incubation atmospheres and may partially explain why C. jejuni bacteremia is so frequently detected. Overall, the Roche Septi-Chek system was excellent for detecting Campylobacter strains in blood cultures
  583. Blaser MJ. "Brainerd diarrhea: a newly recognized raw milk-associated enteropathy [Editorial]". JAMA. 1986 Jul 25;256(4):510-511 (MEDL:3723745 #19302)       
  584. Blaser MJ. "Environmental interventions for the prevention of travelers' diarrhea". Reviews of infectious diseases. 1986 May-Jun;8 Suppl 2(6):S142-S150 (MEDL:3523710 #19306)    

    The diarrheal illnesses affecting travelers to areas with low standards of hygiene are due to exposure to microbial agents not in wide circulation in the travelers' home area. A major objective for the prevention of travelers' diarrhea should be to minimize exposure to these infectious agents. Studies of sporadic and epidemic travelers' diarrhea have shown that contaminated food and water are usually the most important vehicles for transmission of these agents. Travelers must know which foods and water sources to avoid and which they may reasonably be assured are safe. Also, methods for disinfecting potentially contaminated sources must be simple and practical. Acceptable methods for ensuring the safety of food and drink are amply documented in the literature. However, although the consumption of certain foods and beverages is clearly associated with an increased risk of developing travelers' diarrhea, in some retrospective studies adherence to strict dietary rules generally did not appear to diminish the incidence. Despite these findings, whose validity may have been weakened by study design flaws, careful attention to the preparation and choice of food and beverage is recommended for prevention of both diarrheal and nondiarrheal illnesses
  585. Blaser MJ. "Extraintestinal Campylobacter infections [Editorial]". Western journal of medicine. 1986 Mar;144(3):353-354 (MEDL:3962298 #19308)    
  586. Blaser MJ. "Infectious diarrheas: acute, chronic, and iatrogenic". Annals of internal medicine. 1986 Nov;105(5):785-787 (MEDL:3767155 #19301)    
  587. Blaser MJ. "Insect-borne transmission of AIDS [Letter]". JAMA. 1986 Jan 24-31;255(4):463-464 (MEDL:3941526 #19315)       
  588. Blaser MJ; Cody HJ. "Methods for isolating Campylobacter jejuni from low-turbidity water". Applied & environmental microbiology. 1986 Feb;51(2):312-315 (MEDL:3954345 #19311)    

    Membrane filtration methods were developed and evaluated for the quantitative recovery of Campylobacter jejuni from environmental waters of low turbidity. The best procedure studied involved passaging the test water through a filter (pore size, 0.45 micron) and plating it facedown on Campylobacter-selective agar. The filter was removed after overnight incubation, and the plate was streaked for isolation and then reincubated. This method, with or without prefiltration through 5.0- and 0.6-micron-pore-size membranes consistently resulted in the recovery of 30 C. jejuni CFU/250 ml of seeded natural waters. The other methods, plating the final filter face-up or preincubation of the filter in an enrichment medium, were not as sensitive. The technique described above could be useful in the routine monitoring of finished waters for C. jejuni or during investigations of suspected waterborne outbreaks for water of low turbidity
  589. Blaser MJ; Cohn DL. "Opportunistic infections in patients with AIDS: clues to the epidemiology of AIDS and the relative virulence of pathogens". Reviews of infectious diseases. 1986 Jan-Feb;8(1):21-30 (MEDL:3006206 #19321)    

    The frequency of nine reactivating or opportunistic infections and Kaposi's sarcoma among patients with the acquired immunodeficiency syndrome (AIDS) was reviewed. The diagnoses of 87 patients reported from the Colorado AIDS registry and 359 others from literature reports were abstracted, and data were placed in one of 11 categories on the basis of the risk group of the patient. Pneumocystis carinii infection was significantly commoner among blood or blood-product recipients than among natives of the tropics (P less than .001). Tuberculosis and toxoplasmosis each were significantly commoner among natives of the tropics than natives of developed countries (P less than .001), whereas disseminated Mycobacterium avium-Mycobacterium intracellulare infections were present more often in the latter group. Among natives of the tropics treated in developed countries, cytomegaloviral infection was diagnosed significantly less often (22%) than among persons from developed countries in whom sexual transmission was presumed (47%; P = .0005). These data suggest that the pattern of infections manifested in AIDS could provide clues about transmission and that there may be a hierarchy of reactivation of latent infections in which populations with exposure to multiple agents manifest these preferentially to Pneumocystis carinii
  590. Blaser MJ; Cohn DL; Cody HJ; Penley KA; Judson FN; Saxinger WC; Weiss SH. "Counterimmunoelectrophoresis for detection of human serum antibody to HTLV-III". Journal of immunological methods. 1986 Jul 24;91(2):181-186 (MEDL:3016097 #19303)       

    We examined the usefulness of a counterimmunoelectrophoresis (CIE) technique for detecting antibodies to HTLV-III using sera that previously had been assessed for antibodies to HTLV-III by the standard enzyme-linked immunosorbent assay (ELISA). We selected a subset of 53 sera from patients with the acquired immune deficiency syndrome (AIDS) or the generalized lymphadenopathy syndrome (GLS) in which 81.1% were initially ELISA-positive, and 96.2% were positive by Western blot technique. In our standard HTLV-III CIE technique, 58.5% were positive and repeat testing increased the yield to 67.9%. Varying several parameters of the standard CIE assay did not improve sensitivity. We also studied 20 ELISA-negative and 10 ELISA-borderline sera from normal controls; all were negative by CIE. These results indicate that CIE may be used for detection of human serum antibodies to HTLV-III, but that the present assay was less sensitive than the HTLV-III ELISA
  591. Blaser MJ; Hopkins JA; Perez-Perez GI; Cody HJ; Newell DG. "Antigenicity of Campylobacter jejuni flagella". Infection & immunity. 1986 Jul;53(1):47-52 (MEDL:3522430 #19304)    

    We studied the antigenicity of a wild-type flagellate and motile (F+M+) Campylobacter jejuni strain (81116) and two daughter mutants, one flagellate and immotile (F+M-) and one aflagellate and immotile (F-M-). By sodium dodecyl sulfate-polyacrylamide gel electrophoresis of acid-extracted surface proteins, a 63-kilodalton (kDa) band identified from sheared flagella as the flagellar protein was present in the F+M+ and F+M- strains but not in the F-M- strain. No other differences in protein profile among the three strains were noted. By Western blotting, serum from rabbits immunized with either the F+M+ or F-M- strain detected a 63-kDa protein in the F+M+ and F+M- strains but not in the F-M- strain. That the F-M- antiserum recognized the 63-kDa band suggests that small amounts of this protein or a cross-reacting antigen is present on the F-M- strain. By counterimmunoelectrophoresis of the acid-extracted preparations with immune sera, all three strains were found to share three major antigens, but a fourth antigen with a net positive charge was present only in the F+M+ and F+M- strains. Antisera to five C. jejuni and two Campylobacter fetus strains recognized the 63-kDa protein of purified F+M+ flagella in Western blots, demonstrating a common antigen is present, but enzyme-linked immunosorbent assay results suggest that the sharing of this antigen among Campylobacter strains is variable
  592. Blaser MJ; Perez GP; Smith PF; Patton C; Tenover FC; Lastovica AJ; Wang WI. "Extraintestinal Campylobacter jejuni and Campylobacter coli infections: host factors and strain characteristics". Journal of infectious diseases. 1986 Mar;153(3):552-559 (MEDL:3512731 #19309)       

    To determine whether extraintestinal isolates of Campylobacter jejuni and Campylobacter coli are the consequence of unusual host or bacterial characteristics, we studied clinical and bacteriologic features of 24 extraintestinal infections. Common serotypes and auxotypes were present among the extraintestinal isolates. Gastrointestinal isolates were more susceptible to normal human serum than were the systemic isolates; however, the ranges overlapped considerably. Predispositions to systemic spread were present in 52% of patients with extraintestinal infections; isolates from these patients were more often (73%) serum sensitive than were isolates from patients without predispositions (9%; P = .002). By sodium dodecyl sulfate-polyacrylamide gel electrophoresis, no specific protein band was associated with serum resistance, and all isolates of C. jejuni and C. coli had rough-type lipopolysaccharide profiles. Serum susceptibility was inversely correlated with carbohydrate or ketodeoxyoctonate (KDO) fraction of cell weight and directly correlated with KDO:carbohydrate ratio. Our results suggest that either host defects or specific bacterial virulence characteristics, such as serum resistance, possibly related to length of lipopolysaccharide side chain, may be responsible for extraintestinal infections due to C. jejuni and C. coli
  593. Blaser MJ; Smith PF; Wang WL; Hoff JC. "Inactivation of Campylobacter jejuni by chlorine and monochloramine". Applied & environmental microbiology. 1986 Feb;51(2):307-311 (MEDL:3954344 #19312)    

    Campylobacter jejuni and closely related organisms are important bacterial causes of acute diarrheal illness in the United States. Both endemic and epidemic infections have been associated with consuming untreated or improperly treated surface water. We compared susceptibility of three C. jejuni strains and Escherichia coli ATCC 11229 with standard procedures used to disinfect water. Inactivation of bacterial preparations with 0.1 mg of chlorine and 1.0 mg of monochloramine per liter was determined at pH 6 and 8 and at 4 and 25 degrees C. Under virtually every condition tested, each of the three C. jejuni strains was more susceptible than the E. coli control strain, with greater than 99% inactivation after 15 min of contact with 1.0 mg of monochloramine per liter or 5 min of contact with 0.1 mg of free chlorine per liter. Results of experiments in which an antibiotic-containing medium was used suggest that a high proportion of the remaining cells were injured. An animal-passaged C. jejuni strain was as susceptible to chlorine disinfection as were laboratory-passaged strains. These results suggest that disinfection procedures commonly used for treatment of drinking water to remove coliform bacteria are adequate to eliminate C. jejuni and further correlate with the absence of outbreaks associated with properly treated water
  594. Blaser MJ; Taylor DN; Echeverria P. "Immune response to Campylobacter jejuni in a rural community in Thailand". Journal of infectious diseases. 1986 Feb;153(2):249-254 (MEDL:3944480 #19313)       

    We studied the prevalence of antibodies to Campylobacter jejuni in serum from healthy Thai villagers by using enzyme-linked immunosorbent assays with C. jejuni surface proteins as antigens. Levels of C. jejuni-specific IgA rose progressively through life, IgG peaked in the second year of life and then fell, and IgM peaked during late childhood and the teenage years. These findings confirm results observed in Bangladeshi children, and they suggest there is intense early exposure and continued exposure through life. The ratio of C. jejuni-specific IgA to total IgA was constant in all age groups while the ratio of specific IgG and IgM followed the same age-related pattern as the levels of antibody to C. jejuni. The age-related discordance between the C. jejuni-specific IgA and IgG levels observed in this and the previous study are at present unexplained
  595. Blaser, Martin J; Hopkins, Janet A; Perez-Perez, Guillermo I; Cody, Henry J; Newell, Diane G. Antigenicity of Campylobacter Jejuni Flagella. [Alexandria, VA] : Ft. Belvoir Defense Technical Information Center, 1986. 7 p..   

    We studied the antigenicity of a wild-type flagellate and motile F(+) M(+) Campylobacter jejuni strain (81116) and two daughter mutants, one flagellate and immotile F (+)M(-) and one aflagellate and immotile F(-)M(-). By solium dodecyl sulfate-polyacrylamide gel electrophoresis of acid-extracted surface proteins, a 63-kilodalton (kDa) band identified from sheared flagella as the flagellar protein was present in the F(+)M(+) and F(+)M(-) strains but not in the F(-)M(-) strain. No other differences in protein profile among the three strains were noted. By Western blotting, serum from rabbits immunized with either the F(+)M(+) or F(-)M(-) strain detected a 63-kDa protein in the F(+)M(+) and F(+)M(-) strains but not in the F(-)M(-) strain. That the F(-)M(-) antiserum recognized the 63-kDa band suggests that small amounts of this protein or a cross-reacting antigen is present on the F(-)M(-) strain. By counterimmunoelectrophoresis of the acid-extracted preparations with immune sera, all three strains were found to share three major antigens, but a fourth antigen with a net positive charge was present only in the F(+)M(+) and F(+)M(-) strains. Antisera to five C. jejuni and two Campylobacter fetus strains recognized the 63-kDa protein oif purified F(+)M(+) flagella in Western blots, demonstrating that a common antigen is present, but enzyme-linked immunosorbent assay results suggest that the sharing of this antigen among Campylobacter strains is variable
  596. Blaser, Martin J; Perez, Guillermo; Smith, Paul F; Patton, Charlotte; Fenover, Fred C. Extraintestinal Campylobacter Jejuni and Campylobacter Coli Infections: Host Factors and Strain Characteristics. [S.l.] : Ft. Belvoir Defense Technical Information Center, 1986. 9 p..   

    To determine whether extraintestinal isolates of Campylobacter jejuni and Campylobacter coli are the consequence of unusual host or bacterial characteristics, we studied clinical and bacteriologic features of 24 extraintestinal infections. Common serotypes and auxotypes were present among the extraintestinal isolates. Gastrointestinal isolates were more susceptible to normal human serum than were the systemic isolates; however, the ranges overlapped considerably. Predispositions to systemic spread were present in 52% of patients with extraintestinal infections; isolates from these patients were more often (73%) serum sensitive than were isolates from patients without predispositions (9%; P = .002). By sodium dodecyl sulfate-polyacrylamide gel electrophoresis, no specific protein band was associated with serum resistance, and all isolates of C. jejuni and C. coli had rough-type lipopolysaccharide profiles. Serum susceptibility was inversely correlated with carbohydrate or ketodeoxyoctonate (KDO) fraction of cell weight and directly correlated with KDO:carbohydrate ratio. Our results suggest that either host defects or specific bacterial virulence characteristics, such as serum resistance, possibly related to length of lipopolysaccharide side chain, may be responsible for extraintestinal infections due to C. jejuni and C. coli
  597. Blaser, Martin J; Taylor, David N; Echeverria, Peter. Immune response to campylobacter jejuni in a rural community in Thailand. [S.l.] : Ft. Belvoir Defense Technical Information Center, 1986. 5 p..   

    We studied the prevalence of antibodies to Campylobacter jejuni in serum from healthy Thai villagers by using enzyme-linked immunosorbent assays with C. jejuni surface proteins as antigens. Levels of C. jejuni-specific IgA rose progressively through life, IgG peaked in the second year of life and then fell, and IgM peaked during late childhood and the teenage years. These findings confirm results reserved in Bangladeshi children, and they suggest there is intense early exposure and continued exposure through life. The ratio of C. jejuni-specific IgA to total IgA was constant in all age groups while the ratio of specific IgG and IgM followed the same age-related pattern as the levels of antibody to C. jejuni. The age-related discordance between the C. jejuni- specific IgA and IgG levels observed in this and the previous study are at present unexplained
  598. Ciesielski CA; Blaser MJ; Wang WL. "Serogroup specificity of Legionella pneumophila is related to lipopolysaccharide characteristics". Infection & immunity. 1986 Feb;51(2):397-404 (MEDL:2417953 #19314)    

    We studied the lipopolysaccharide (LPS) of Legionella pneumophila and six other Legionella species to determine whether strain differences were apparent. The LPS was purified by a cold ethanol extraction procedure, and total carbohydrates represented 10 to 20% of LPS weight. 2-keto-3-deoxyoctonate represented 1 to 13% of the total carbohydrate present in the LPS. By sodium dodecyl sulfate-polyacrylamide gel electrophoresis, all strains except L. dumoffi showed smooth-type LPS with multiple high-molecular-weight complexes. Proteinase K-treated, whole-cell lysates showed profiles similar to those of purified LPS. Each serogroup of L. pneumophila and each Legionella species had a distinct sodium dodecyl sulfate-polyacrylamide gel electrophoresis profile. L. pneumophila lipid A is antigenically related to the lipid A of Enterobacteriaceae. In immunoblot assays with the LPS of L. pneumophila serogroups 1 to 6 as antigens, serogroup-specific immune monkey sera recognized homologous purified LPS, but not the LPS of the five heterologous serogroups. These studies indicate that LPS composition may be a determinant of serogroup specificity as defined by the immunofluorescence-based serogrouping schema for L. pneumophila and other Legionella species
  599. Cooper ER; Ellison RT; Smith GS; Blaser MJ; Reller LB; Paisley JW. "Rifampin-resistant meningococcal disease in a contact patient given prophylactic rifampin". Journal of pediatrics. 1986 Jan;108(1):93-96 (MEDL:3080574 #19319)       
  600. Dobozin BS; Judson FN; Cohn DL; Penley KA; Rickmann PE; Blaser MJ; Sarin PS; Weiss SH; Kirkpatrick CH. "The relationship of abnormalities of cellular immunity to antibodies to HTLV-III in homosexual men". Cellular immunology. 1986 Mar;98(1):156-171 (MEDL:3017581 #19310)       

    A comprehensive evaluation of the cellular immune system (total T-cell, helper cell, suppressor cell, and natural killer cell numbers; in vitro interleukin-2 production, T-cell responses to mitogens and antigens, serum beta 2 microglobulin levels, and delayed hypersensitivity skin tests) was performed on 36 HTLV-III seronegative and 16 HTLV-III seropositive healthy homosexual men, 48 asymptomatic homosexual men with the chronic lymphadenopathy syndrome, 41 patients with AIDS, and 29 heterosexual controls without any known risk factors for AIDS. Our studies demonstrate that HTLV-III seronegative homosexual men have normal cellular immunity and are comparable to heterosexual controls. The abnormalities of lymphocyte subsets observed in HTLV-III seropositive healthy homosexual men are comparable to subjects with chronic lymphadenopathy. Assays of lymphocyte function, with the exception of delayed type hypersensitivity (DTH) skin tests, are similar in each group except patients with AIDS. Subjects with chronic lymphadenopathy were less responsive to DTH skin tests and HTLV-III seropositive healthy homosexuals were comparable to chronic lymphadenopathy subjects. We conclude that immunologic abnormalities in homosexual men are attributable to infection with HTLV-III
  601. Klein BS; Vergeront JM; Blaser MJ; Edmonds P; Brenner DJ; Janssen D; Davis JP. "Campylobacter infection associated with raw milk. An outbreak of gastroenteritis due to Campylobacter jejuni and thermotolerant Campylobacter fetus subsp fetus". JAMA. 1986 Jan 17;255(3):361-364 (MEDL:3753617 #19316)       

    Raw milk is identified with increasing numbers of outbreaks of gastroenteritis and is an important vehicle for transmission of Campylobacter infection. Unlike Campylobacter jejuni, Campylobacter fetus subsp fetus has not been associated with common-source outbreaks of gastroenteritis. This report describes an outbreak of gastroenteritis involving C jejuni and a thermotolerant strain of C fetus subsp fetus associated with raw milk. Fifteen (39%) of 38 persons who attended a banquet in Wisconsin in June 1982 developed acute gastroenteritis. Stool specimens were obtained from nine ill guests; four yielded C jejuni and three yielded C fetus subsp fetus. The C fetus subsp fetus isolates were identified fortuitously, in part because of unusual thermotolerance (growth at 42 degrees C), permitting isolation at temperature appropriate for C jejuni. Survey results implicated raw milk as the source of the outbreak. Findings provide evidence of a potentially emergent milkborne pathogen contributing to the risk of raw milk consumption and suggest that current diagnostic laboratory techniques may fail to identify significant foodborne agents
  602. Pandey JP; Blaser MJ. "Heterozygosity at the Km locus associated with humoral immunity to Campylobacter jejuni". Experimental & clinical immunogenetics. 1986;3(1):49-53 (MEDL:3274046 #19318)    

    Serum samples from 43 Caucasian subjects convalescing from acute Campylobacter jejuni infection were typed for nine Gm and two Km determinants. The sera were also used to measure IgA, IgG, and IgM classes of antibody to acid-labile surface proteins of C. jejuni by an enzyme-linked immunosorbent assay. A highly significant association (p = 0.004) was found between Km1/Km3 heterozygotes and the level of IgA antibodies. These results suggest the existence of complementary immune response genes which in the heterozygous condition permit a humoral response to C. jejuni
  603. Perez-Perez GI; Blaser MJ; Bryner JH. "Lipopolysaccharide structures of Campylobacter fetus are related to heat-stable serogroups". Infection & immunity. 1986 Jan;51(1):209-212 (MEDL:3510169 #19317)    

    To determine whether lipopolysaccharide (LPS) structures of Campylobacter fetus are related to the three known heat-stable serogroups, proteinase K-treated whole cell lysates obtained from strains of each serogroup were electrophoresed in polyacrylamide gels. All strains had smooth-type LPS with multiple high-molecular-weight repeating units. The profiles of serogroup A from C. fetus subsp. fetus and from C. fetus subsp. venerealis were identical, but they were different from those of C. fetus subsp. fetus serogroups B and AB. When we immunoblotted the LPS of these serogroups with normal or immune rabbit serum we found homologous recognition between serogroups A from C. fetus subsp. fetus and C. fetus subsp. venerealis. Similarly, serogroups AB and B from C. fetus subsp. fetus showed homologous recognition. However, antiserum against serogroup A did not recognize serogroups B and AB and vice versa. Absorption studies confirmed the identity of LPS from all serogroup A C. fetus strains and cross-reactivity of the serogroup B and AB strains with one another. Serogroup A strains were resistant to the bactericidal activity in normal human serum, whereas serogroup B and AB strains generally were susceptible; isolates from humans predominantly belonged to serogroup A. Results of these studies suggest that the LPS composition forms the basis for the heat-stable serotyping system for C. fetus and that the structural and antigenic variants are associated with differential serum susceptibility
  604. Perez-Perez GI; Hopkins JA; Blaser MJ. "Lipopolysaccharide structures in Enterobacteriaceae, Pseudomonas aeruginosa, and Vibrio cholerae are immunologically related to Campylobacter spp". Infection & immunity. 1986 Jan;51(1):204-208 (MEDL:3079730 #19320)    

    To determine whether lipopolysaccharide (LPS) structures of Campylobacter species are immunologically related to those of 11 other gram-negative organisms, we immunoblotted from polyacrylamide gels the LPS of these strains with immune rabbit serum raised against six Campylobacter jejuni strains and two Campylobacter fetus strains. The LPS studied were from Salmonella minnesota wild type and Ra to Re mutants, Salmonella typhi, Escherichia coli, Yersinia enterocolitica, Vibrio cholerae, and Pseudomonas aeruginosa. None of the 11 LPS preparations was recognized by the eight antisera, but antisera to each of the Campylobacter strains recognized core determinants of some LPS preparations. Antiserum directed against the most serum-sensitive C. jejuni strain, 79-193, was the only antiserum sample that recognized core regions of the rough Salmonella mutants. In converse experiments, when LPS preparations from five Campylobacter strains were blotted with antiserum to Salmonella lipid A, recognition of core structures of each was shown; data from an enzyme-linked immunosorbent assay confirmed this result. In contrast, antiserum to Salmonella typhimurium Re LPS showed no reactivity. We conclude that LPS of Campylobacter strains share lipid A antigenic determinants with the core region of LPS of several other gram-negative organisms
  605. Perez-Perez, Guillermo I; Blaser, Martin J; Bryner, John H. Lipopolysaccharide Structures of Campylobacter fetus are Related to Heat-Stable Serogroups. [Alexandria, VA] : Ft. Belvoir Defense Technical Information Center, 1986. 5 p..   

    To determine whether lipopolysaccharide (LPS) structures of Campylobacter fetus are related to the three known heat-stable serogroups, proteinase K-treated whole cell lysates obtained from strains of each serogroup were electrophoresed in polyacrylamide gels. All strains had smooth-type LPS with multiple high-molecular-weight repeating units. The profiles of serogroup A from C. fetus subsp. fetus and from C. fetus subsp. venerealis were identical, but they were different from those of C. fetus susp. fetus serogroups B and AB. When we immunoblotted the LPS of these serogroups with normal or immune rabbit serum we found homologous recognition between serogroups A from C. fetus subsp. fetus and C. fetus subsp. venerealis. Similarly, serogroups AB and B from C. fetus subsp. fetus showed homologous recognition. However, antiserum against serogroup A did not recognize serogroups B and AB and vice versa. Absorption studies confirmed the identity of LPS from all serogroup A C. fetus strains and cross-reactivity of the serogroup B and AB strains with one another. Serogroup A strains were resistant to the bactericidal activity in normal human serum, whereas serogroup B and AB strains generally were susceptible; isolates humans predominantly belonged to serogroup A. Results of these studies suggest that the LPS composition forms the basis for the heat-stable serotyping system for C. fetus and that the structural and antigenic variants are associated with differential serum susceptibility
  606. Wang WL; Blaser MJ. "Detection of pathogenic Campylobacter species in blood culture systems". Journal of clinical microbiology. 1986 Apr;23(4):709-714 (MEDL:3700626 #19307)    

    Because differences in recognition of Campylobacter fetus and Campylobacter jejuni in systemic infections may be due partially to differences in the ability to cultivate these organisms, we studied their growth characteristics in two widely used blood culture systems. In the Roche Septi-Chek system (Hoffman-La Roche, Inc., Nutley, N.J.), over a broad range of inocula all strains were detected in broth within 2 days and on paddles within 3 days. In the BACTEC 6B aerobic bottles (Johnston Laboratories, Inc., Towson, Md.), C. jejuni and C. fetus took a median of 5 and 3 days, respectively, to reach the growth index threshold. However, in the BACTEC 7D anaerobic bottles, C. fetus required a median of 2 days to reach the growth index threshold, whereas for C. jejuni the median was greater than 10 days. The poor performance of C. jejuni in both BACTEC systems may have been due to unfavorable incubation atmospheres and may partially explain why C. jejuni bacteremia is so infrequently detected. Overall, the Roche Septi-Chek system was excellent for detecting Campylobacter strains in blood cultures
  607. Weiss SH; Blaser MJ; Paleologo FP; Black RE; McWhorter AC; Asbury MA; Carter GP; Feldman RA; Brenner DJ. "Occurrence and distribution of serotypes of the Arizona subgroup of Salmonella strains in the United States from 1967 to 1976". Journal of clinical microbiology. 1986 Jun;23(6):1056-1064 (MEDL:3711296 #19305)    

    The Salmonella Arizona subgroup contains gram-negative enteric bacteria that are closely related to other salmonellae biochemically, serologically, and genetically. Although the Arizona subgroup may be isolated from a wide variety of nonhuman and human sources, the arizonae are uncommonly recognized as human pathogens, and surprisingly little is known about their epidemiology. From 1967 through 1976, the Centers for Disease Control received 858 Arizona subgroup cultures from human and nonhuman sources representing 143 different serotypes in 33 somatic groups; several serotypes had not been previously reported. The 374 cultures from humans represent 71 different serotypes; extraintestinal isolates were present in 31 (44%) serotypes. Compared with data from a previous 20 years of surveillance, the proportion of Arizona subgroup strains isolated from stools, blood, and other sites was remarkably stable, but several serotypes showed marked changes in their frequency of isolation. In total, the ratio of extraintestinal to intestinal isolates was 0.37, but marked serotype-specific variation was noted, suggesting differences in virulence associated with serotype
  608. Blaser MJ; Black RE; Duncan DJ; Amer J. "Campylobacter jejuni-specific serum antibodies are elevated in healthy Bangladeshi children". Journal of clinical microbiology. 1985 Feb;21(2):164-167 (MEDL:3972984 #19328)    

    In Bangladesh and other developing countries, isolation of Campylobacter jejuni is common in healthy children, and the illness/infection ratio falls with age. To determine whether specific serum antibodies correlate with this phenomenon, using an enzyme-linked immunosorbent assay, we studied sera from 93 healthy Bangladeshi children and 121 healthy U.S. children under 15 years of age. For each age group (less than 1, 2 to 4, and 5 to 14 years) studied, specific serum antibody levels were significantly higher in the Bangladeshi children. Among Bangladeshi children, for each of the three immunoglobulin subclasses, the change in antibody levels with age was different. Specific immunoglobulin A antibody levels rose linearly with age, immunoglobulin G levels peaked in the 2- to 4-year age group and then fell, and immunoglobulin M levels peaked in the 2- to 4-year age group and then plateaued. Elevated serum antibody levels to C. jejuni in Bangladeshi children may be protective in themselves or may reflect other protective phenomena
  609. Blaser MJ; Ellison RT. "Rapid nighttime evacuation of a veterans hospital". Journal of emergency medicine. 1985;3(5):387-394 (MEDL:3835193 #19332)    

    Loss of essential utilities and danger of explosion forced a rapid nighttime winter evacuation of 229 patients from an acute-care Veterans Administration hospital. Although distribution of patients to recipient hospitals was not optimal, and the location of several patients could not be documented for more than 24 hours, the evacuation in subfreezing weather went smoothly. Continuity of care and careful planning permitted an orderly return to the hospital five days later. Although financial costs were high, no excess mortality or morbidity was associated with the evacuation. No changes in pharyngeal gram-negative bacterial flora of the patients were noted. Further, a critique is presented to aid in planning for similar emergencies elsewhere
  610. Blaser MJ; Patton CM. "Campylobacter enteritis associated with foodborne transmission: new serotyping data [Letter]". American journal of epidemiology. 1985 Apr;121(4):625-626 (MEDL:4014153 #19326)    
  611. Blaser MJ; Smith PF; Kohler PF. "Susceptibility of Campylobacter isolates to the bactericidal activity of human serum". Journal of infectious diseases. 1985 Feb;151(2):227-235 (MEDL:3968449 #19329)       

    Although Campylobacter jejuni and related thermophilic organisms are more common human pathogens than are Campylobacter fetus, most bloodstream or systemic isolates are C. fetus. To understand the pathophysiology related to this observation, the authors studied susceptibility to the bactericidal activity of normal human serum of Campylobacter coli, C. jejuni, and C. fetus isolates from feces and blood. In standardized assays, 10 of 15 C. jejuni and related isolates showed 90% kill (mean, 90.6% +/- 5.9); under more stringent conditions, the relatively resistant strains were completely killed. In contrast, all C. fetus strains were highly serum resistant under both standard and stringent conditions. Killing of C. jejuni was ablated by heating serum to 56 C but restored by addition of complement. Both classical and alternative complement pathways may contribute to killing, and adsorption studies demonstrated antibody dependence. Serum resistance may permit systemic infection by C. fetus, whereas complement- and antibody-mediated serum sensitivity of C. jejuni may account for the relative infrequency of systemic invasion
  612. Brown A; Lema M; Ciesielski CA; Blaser MJ. "Combined plasmid and peptide analysis of clinical and environmental Legionella pneumophila strains associated with a small cluster of Legionnaires' disease cases". Infection. 1985 Jul-Aug;13(4):163-166 (MEDL:4044043 #19322)       

    Plasmid and peptide analysis was used to characterize Legionella pneumophila strains isolated in the study of a small cluster of cases in hospitalized patients. The isolates from the Denver Veterans' Administration Medical Center could be clearly separated into three groups. Two of the three clinical isolates were found to be plasmidless, as were five of 19 environmental isolates. The patient isolates had plasmid and peptide profiles which were identical to the showerhead isolates to which each patient was exposed. Thus, the data suggest that the patients acquired their disease strains from environmental sites in their particular hospital wing, and that each wing of the building had its own unique flora of Legionella strains. The results also confirm the usefulness of using both these techniques when tracing transmission patterns of nosocomial disease
  613. Horton JM; Blaser MJ. "The spectrum of relapsing fever in the Rocky Mountains". Archives of internal medicine. 1985 May;145(5):871-875 (MEDL:3994463 #19324)       

    Between 1940 and 1976, two cases of tick-borne relapsing fever were reported in Colorado, but since 1977, 23 confirmed cases have occurred. All patients had fever, with a mean of 2.8 febrile episodes (range, one to six). Complications included thrombocytopenia, endophthalmitis, meningitis, abortion, in utero infection, and erythema multiforme. All treated patients were eventually cured with antibiotics, although two pregnant patients failed to be cured by their initial courses of antibiotics. Seven of 21 treated patients had Jarisch-Herxheimer reactions, three of whom required intensive care. Five of nine patients who received tetracycline at an initial dose of 5 mg/kg or more had reactions v none of four patients treated with lower doses. Possible causes of the recent increased incidence include increased physician awareness and reporting, improved diagnostic techniques, and an actual increase due to a larger population at risk. Because summertime visits to the Rocky Mountains are becoming increasingly popular, physicians elsewhere should know how to recognize and treat this condition
  614. Parkhurst SM; Blaser MJ; Laxson LB; Wang WL. "Surveillance for the detection of nosocomial infections and the potential for nosocomial outbreaks. II. Development of a laboratory-based system". American journal of infection control. 1985 Feb;13(1):7-15 (MEDL:3844913 #19331)       

    We describe the development of a surveillance system that uses thresholds for detecting nosocomial infections and the potential for nosocomial outbreaks based on data from microbiology laboratory records at our hospital from 1980 to 1982. These records were monitored weekly to determine the number of positive isolates by the identity of the organism and by the site of the culture. A mean of 225 specimens was processed weekly, with 60 of these yielding bacteria or fungi. The average number of organisms isolated per positive culture was 1.46. Two methods of establishing thresholds were compared, one based on percentiles of ranked isolates, the other based on the mean plus intervals of standard error. The system using thresholds established by the standard error method was consistently more useful to highlight weeks for which there was high risk of a problem occurring in less time than were the surveillance techniques traditionally employed
  615. Perez GI; Hopkins JA; Blaser MJ. "Antigenic heterogeneity of lipopolysaccharides from Campylobacter jejuni and Campylobacter fetus". Infection & immunity. 1985 May;48(2):528-533 (MEDL:2580793 #19325)    

    The lipopolysaccharide (LPS) structure of Campylobacter spp. can be visualized with polyacrylamide gel electrophoresis by examining proteinase K-treated whole cell lysates. Polyacrylamide gel electrophoresis LPS profiles of C. jejuni strains are rough type with low concentrations of low-molecular-weight polysaccharide side chains, serum-resistant C. fetus strains have smooth-type LPS, and serum-sensitive C. fetus strains have rough-type LPS. We electroblotted the proteinase K-treated whole cell lysates of 17 C. jejuni and 9 C. fetus strains from polyacrylamide gel electrophoresis to nitrocellulose paper to examine antigenicity to immune rabbit sera. There was virtually no antigenic cross-reactivity of C. jejuni and C. fetus LPS. Among C. jejuni strains, core LPS structures were cross-reactive, but the O-polysaccharide side chains were best recognized by homologous antisera. Antisera to several serum-resistant C. fetus strains recognized only the polysaccharide side-chain regions of serum-resistant strains and no part of the LPS from the sensitive strain. Antiserum raised against a serum-sensitive C. fetus strain but not homologous antisera recognized the core region of the LPS of the serum-resistant C. fetus strains. These findings suggest that core LPS antigens are widely shared within C. fetus subsp. fetus strains but that in the serum-resistant strains this core region is not surface exposed and therefore not immunogenic to rabbits infected with whole cells
  616. Perez Perez GI; Blaser MJ. "Lipopolysaccharide characteristics of pathogenic campylobacters". Infection & immunity. 1985 Feb;47(2):353-359 (MEDL:3967920 #19330)    

    Most Campylobacter jejuni strains are sensitive and most Campylobacter fetus strains are resistant to the bactericidal activity in normal human serum. We purified lipopolysaccharides from Campylobacter strains to determine whether their composition and structure relate to serum susceptibility. The lipopolysaccharide of two serum-sensitive strains was best isolated by the Galanos procedure, but for two serum-resistant strains a cold-ethanol extraction was optimal. For each lipopolysaccharide preparation, the ratio of 2-keto-3-deoxyoctonate to protein was increased by 100 to 1,000-fold over that of whole cells. For serum-resistant strains, total carbohydrates was a high proportion of lipopolysaccharide weight; for serum-sensitive strains, 2-keto-3-deoxyoctanate was a high proportion of total carbohydrates. By polyacrylamide gel electrophoresis, the lipopolysaccharide of serum-sensitive strains appeared rough, but for serum-resistant strains a smooth-type ladder was seen, with a minimal core region and several high-molecular-weight complexes. Proteinase K-treated whole-cell lysates showed polyacrylamide gel electrophoresis profiles similar to that of pure lipopolysaccharide. Proteinase K-treated whole-cell lysates from seven serum-sensitive C. jejuni strains all had rough profiles, and five serum-resistant C. fetus strains all had smooth profiles. These studies indicate that lipopolysaccharide composition may be an important determinant of serum susceptibility among Campylobacter species and that serum resistance is usually associated with a smooth-type lipopolysaccharide
  617. Perez-Perez, Guillermo I; Hopkins, Janet A; Blaser, Martin J. Lipopolysaccharide Structures in Enterobacteriaceae, Pseudomonas Aeruginosa, and Vibrio Cholerae are Immunologically Related to Campylobacter Spp. [Alexandria, VA] : Ft. Belvoir Defense Technical Information Center, 1985. 6 p..   

    To determine whether lipopolysaccharide (LPS) structures of Campylobacter species are immunologically related to those of 11 other gram- negative organisms, we immunoblotted from polyacrylamide gels the LPS of these strains with immune rabbit serum raised against six Campylobacter jejuni strains and two Campylobacter fetus strains. The LPS studied were from Salmonella minnesota wild type and Ra to Re mutants, Salmonella typhi, Escherichia Coli, Yersinia Enterocolitica, Vibrio cholerae, and Pseudomonas aeruginosa. None of the 11 LPS preparations was recognized by the eight antisera, but antisera to each of the Campylobacter strains recognized core determinants of some LPS preparations. Antiserum directed against the most serum-sensitive C. jejuni strain, 79-193, was the only antiserum sample that recognized core regions of the rough Salmonella mutants. In converse experiments, when LPS preparations from five Campylobacter strains were blotted with antiserum to Salmonella lipid A, recognition of core structures of each was shown; data from an enzyme-linked immunosorbent assay confirmed this result. In contrast, antiserum to Salmonella typhimurium Re LPS showed no reactivity. We conclude that LPS of Campylobacter strains share lipid A antigenic determinants with the core region of LPS of several other gram-negative organisms
  618. Perez-Perez, Guillermo I; Hopkins, Janet A; Blaser, Martin J. Lipopolysaccharide Structures in Enterobacteriaceae, Pseudomonas Aeruginosa, and Vibrio Cholerae are Immunologically Related to Campylobacter Spp. [S.l.] : Ft. Belvoir Defense Technical Information Center, 1985. 6 p..   

    To determine whether lipopolysaccharide (LPS) structures of Campylobacter species are immunologically related to those of 11 other gram- negative organisms, we immunoblotted from polyacrylamide gels the LPS of these strains with immune rabbit serum raised against six Campylobacter jejuni strains and two Campylobacter fetus strains. The LPS studied were from Salmonella minnesota wild type and Ra to Re mutants, Salmonella typhi, Escherichia Coli, Yersinia Enterocolitica, Vibrio cholerae, and Pseudomonas aeruginosa. None of the 11 LPS preparations was recognized by the eight antisera, but antisera to each of the Campylobacter strains recognized core determinants of some LPS preparations. Antiserum directed against the most serum-sensitive C. jejuni strain, 79-193, was the only antiserum sample that recognized core regions of the rough Salmonella mutants. In converse experiments, when LPS preparations from five Campylobacter strains were blotted with antiserum to Salmonella lipid A, recognition of core structures of each was shown; data from an enzyme-linked immunosorbent assay confirmed this result. In contrast, antiserum to Salmonella typhimurium Re LPS showed no reactivity. We conclude that LPS of Campylobacter strains share lipid A antigenic determinants with the core region of LPS of several other gram-negative organisms
  619. Smith GS; Blaser MJ. "Fatalities associated with Campylobacter jejuni infections". JAMA. 1985 May 17;253(19):2873-2875 (MEDL:3989964 #19323)       

    Although Campylobacter jejuni is now recognized as a common cause of gastroenteritis, fatalities associated with this infection in the United States have not been previously reported. Two fatalities associated with C jejuni infections occurred over a two-year period in the Denver metropolitan area. The first case was in a previously healthy 26-year-old woman who died following a two-day diarrheal illness. The second case was in a 69-year-old diabetic woman who died 19 hours after developing a gastrointestinal tract illness one day following hospital discharge for an orthopedic procedure. Both patients had taken an antimotility agent. During this same two-year period there were 24.4 reported cases of C jejuni infections per 100,000 population. The death rate per reported case was 2.4 per 1,000, and the overall death rate in the entire five-county population was 0.059 per 100,000 population. The exact causes of death for the two patients are not clear; however, hypokalemia may be a contributing factor, especially since there was no evidence of profound volume depletion in the one patient for whom laboratory data were available. Prompt hospitalization and withholding of antimotility agents may have prevented these deaths
  620. Taylor DN; Echeverria P; Blaser MJ; Pitarangsi C; Blacklow N; Cross J; Weniger BG. "Polymicrobial aetiology of travellers' diarrhoea". Lancet. 1985 Feb 16;1(8425):381-383 (MEDL:2857430 #19327)    

    Of 35 US Peace Corps volunteers in Thailand, 20 (57%) had a total of 30 episodes of diarrhoea during their first 6 weeks in the country. Enteric pathogens were associated with 90% of the episodes. A single pathogen was identified in 17 (57%) episodes, 2-4 pathogens were identified in 10 (33%) episodes, and there were 15 symptomless infections. Enterotoxigenic Escherichia coli (ETEC) was identified in 37% of these episodes, and various salmonella serotypes were isolated in 33%. Infections with 9 other enteric pathogens were also identified: Campylobacter jejuni (17%), Plesiomonas shigelloides (13%), Aeromonas hydrophila (10%), Blastocystis hominis (7%), Norwalk virus (7%), Vibrio parahaemolyticus (3%), non-O1 Vibrio cholerae (3%), Vibrio fluvialis (3%), and rotavirus (3%). In total, 56 enteric infections were documented in 35 volunteers
  621. Blaser MJ. "Nonspecific proctocolitis in northeastern Scotland--another view [Letter]". Gastroenterology. 1984 May;86(5 Pt 1):1003-1004 (MEDL:6706061 #19344)    
  622. Blaser MJ; Duncan DJ. "Human serum antibody response to Campylobacter jejuni infection as measured in an enzyme-linked immunosorbent assay". Infection & immunity. 1984 May;44(2):292-298 (MEDL:6715034 #19343)    

    An enzyme-linked immunosorbent assay was adapted to measure immunoglobulin A (IgA), IgG, and IgM classes of human serum antibody to Campylobacter jejuni. Sera were tested from healthy controls, from ill persons at various intervals after exposure to an epidemiologically implicated vehicle for Campylobacter sp. enteritis, from persons exposed to these same vehicles who remained well, and from persons who chronically drank raw milk. The major antigens in the C. jejuni acid-washed antigen preparations from three different strains all migrated at about 30,000 and 63,000. Persons with Campylobacter enteritis developed rising serum IgA, IgG, and IgM antibodies during the second week after infection; IgG and IgM elevations persisted longer than did IgA. Exposed persons who remained well showed similar, but lower, antibody rises. Chronic raw milk drinkers had elevated IgG levels, but not IgM or IgA levels, whether or not they were acutely exposed to an implicated vehicle
  623. Blaser MJ; Hopkins JA; Vasil ML. "Campylobacter jejuni outer membrane proteins are antigenic for humans". Infection & immunity. 1984 Mar;43(3):986-993 (MEDL:6365789 #19347)    

    All Campylobacter jejuni strains have a major outer membrane protein (OMP) that migrates between a molecular weight of 41,000 (41K) and 45K and represents more than 50% of protein present, plus several more minor bands. Using 125I-radiolabeled C. jejuni cells in a radioimmunoprecipitation procedure to assess whether the OMPs were antigenic, we studied serum from rabbits immunized with C. jejuni cells, from humans convalescent after C. jejuni infection, and from appropriate controls. In this assay, the major OMP was the major antigen for both homologously and heterologously immunized rabbits and infected humans but not for controls. Minor bands at 29K and 50K were also antigenic. We tested human and animal sera in a Western blot procedure using anti-immunoglobulin A (IgA), anti-IgG, or anti-IgM conjugates. Homologous and heterologous immune rabbit serum, but not control serum, recognized a large number of membrane proteins between 15K and 91K, including the major OMP. Both Campylobacter spp.-infected and healthy humans showed IgA, IgG, and IgM responses to the major OMP, although the response was more pronounced in the former group. Sera from infected humans recognized several minor bands to a significantly greater extent than control sera did. Our data suggest that there is antigenic similarity between the OMPs of different C. jejuni strains and that some of these OMPs recognized by infected animals and humans have vaccinogenic potential
  624. Blaser MJ; Hoverson D; Ely IG; Duncan DJ; Wang WL; Brown WR. "Studies of Campylobacter jejuni in patients with inflammatory bowel disease". Gastroenterology. 1984 Jan;86(1):33-38 (MEDL:6689672 #19349)    

    Cultures, serology, and immunohistochemical tests for Campylobacter jejuni were performed on 74 patients with inflammatory bowel disease of various disease activity and in healthy and diseased control populations. Fecal cultures were negative in all groups tested. Antibodies to C. jejuni were assessed both by a complement fixation assay and an enzyme-linked immunosorbent assay to multiple serotypes of the organism. Antibody titers in inflammatory bowel disease patients and control populations were similar, and titers in these groups were significantly lower than in patients with acute Campylobacter enteritis. Intestinal tissues examined for Campylobacter antigens by an indirect fluorescent antibody assay were negative. These data do not etiologically implicate C. jejuni in Crohn's disease or chronic ulcerative colitis
  625. Blaser MJ; Jason JM; Weniger BG; Elsea WR; Finton RJ; Hanson RA; Feldman RA. "Epidemiologic analysis of a cluster of homicides of children in Atlanta". JAMA. 1984 Jun 22-29;251(24):3255-3258 (MEDL:6726999 #19339)       

    Between July 1, 1979, and March 15, 1981, there were 22 unsolved homicides and two unsolved disappearances of Atlanta children. Using epidemiologic methods, we attempted to identify factors that had put children at an increased risk of homicide. That all victims in this cluster were black, killed away from home, and that asphyxiation was overrepresented suggests that the cluster was discrete. The cluster was not homogeneous in relation to location of the victim's area of residence or location of the body; however, the median distance of 9.3 miles from home to body suggests that in some cases a motor vehicle was involved. A neighborhood-based study of the male victims and age- and sex-matched controls showed that victims more often ran errands for money (relative risk, 7.9) and were more often alone on the streets or in shopping centers; therefore, they may have been more approachable than other children in the neighborhood
  626. Blaser MJ; Miller RA; Lacher J; Singleton JW. "Patients with active Crohn's disease have elevated serum antibodies to antigens of seven enteric bacterial pathogens". Gastroenterology. 1984 Oct;87(4):888-894 (MEDL:6468876 #19336)    

    A variety of bacterial pathogens including Campylobacter, Yersinia, Listeria, Brucella, and Mycobacteria have been suggested as potential etiologic agents for Crohn's disease. To assess the role of these organisms we studied responses to eight antigens in sera from patients with active Crohn's disease and healthy age- and sex-matched controls. In complement-fixation assays, the sera from the Crohn's disease patients had enhanced reactivity compared with the control sera to all seven orally ingested pathogens studied; however, only the difference in distribution of titers to Yersinia pseudotuberculosis was statistically significant (p less than 0.0025). There was no difference between the two groups in reactivity to arabinomannan, a common mycobacterial antigen. Seroreactivity to enteric pathogens not resident in the bowel flora probably represents a nonspecific sensitization to cross-reacting antigens. Lack of response to the mycobacterial antigen suggests that widespread mycobacterial disease with high bacillary load is not present in Crohn's disease
  627. Blaser MJ; Reingold AL; Alsever RN; Hightower A. "Primary meningococcal pericarditis: a disease of adults associated with serogroup C Neisseria meningitidis". Reviews of infectious diseases. 1984 Sep-Oct;6(5):625-632 (MEDL:6438765 #19338)    

    Pericarditis due to Neisseria meningitidis is usually a consequence of meningeal disease or meningococcemia. This presentation includes a case report of primary meningococcal pericarditis (PMP) and a review of the clinical and epidemiologic features of 15 previously reported cases. All cases have been reported in the past 15 years. Most patients were older teenagers or adults. The median age and age distribution of PMP cases in the United States were significantly greater than that of patients with other meningococcal diseases reported to the Centers for Disease Control (CDC) (P = .005). Similarly, serogroup C N. meningitidis was isolated from 88% of U.S. patients with PMP, compared with isolation from 22% of patients with other meningococcal diseases reported to the CDC (P = .00016). Culture of pericardial fluid usually yielded meningococci, and most patients presented with signs and symptoms typical of purulent pericarditis. A positive pericardial culture was associated with the development of cardiac tamponade (P = .03). With appropriate antibiotic treatment and drainage of pericardial fluid when indicated, all 16 patients survived and experienced few or no sequelae
  628. Blaser MJ; Smith PF; Cody HJ; Wang WL; LaForce FM. "Killing of fabric-associated bacteria in hospital laundry by low-temperature washing". Journal of infectious diseases. 1984 Jan;149(1):48-57 (MEDL:6693789 #19348)       

    Hospitals using 71.1 C water for laundering consume vast amounts of energy. We studied whether washing at 22 C would result in fabric-associated bacterial counts significantly different from those remaining after the high-temperature wash procedure in general use. Using a standard method to enumerate fabric-associated bacteria, we found that soiled sheets and terry cloth items were contaminated, respectively, with 10(6) and 10(8) cfu/100 cm2 of fabric area, predominantly gram-negative rods (especially Enterobacteriaceae and Pseudomonadaceae). Staphylococcus species were the most common gram-positive organisms. A standard low-temperature washing cycle without laundry chemicals removed 3 log10 of bacteria by agitation, dilution, and drainage. When low-temperature laundry chemicals were used, 3 log10 of bacteria were killed after the bleach was added, and sheets and terry cloth items had postwash colony counts of 10(1)-10(2) cfu/100 cm2. Drying removed an additional 1-2 log10 organisms. Bacterial counts and species from low- and high-temperature washed fabrics were comparable. Low-temperature washing is therefore as effective as high-temperature washing for eliminating pathogenic bacteria from hospital laundry
  629. Blaser, Martin J. Studies of the Outer Membrane Proteins of Campylobacter Jejuni for Vaccine Development. [S.l.] : Ft. Belvoir Defense Technical Information Center, 1984. 55 p..

    The major objective of our fifteen months of study was to develop methods for isolating outer membrane-enriched fractions of Campylobacter jejuni. Using standard disruption and solubilization techniques, we have prepared outer membrane-enriched fractions of C. jejuni and have characterized the proteins resolved. Subsequently, we began studies to determine which are antigenic and thus could have potential as vaccine candidates. Using both radioimmunoprecipitation and immunoblot procedures, we have acquired preliminary data on the antigenicity of these proteins. Currently, we have continued to explore the feasibility of using mice for an animal model of Campylobacter infection in which to test vaccine candidates. After original characterization of the consequences of oral challenge, we have focused on determining the kinetics of the bacteremia produced, and the mechanisms for clearance. We have also developed an enzyme-linked immunosorbent assay (ELISA) for determining human IgA, IgG, and IgM responses to C. jejuni surface antigens. This technique will be of value at the time human subjects are challenged with candidate vaccines
  630. Buchwald DS; Blaser MJ. "A review of human salmonellosis: II. Duration of excretion following infection with nontyphi Salmonella". Reviews of infectious diseases. 1984 May-Jun;6(3):345-356 (MEDL:6377442 #19346)