Faculty Bibliography

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

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

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

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

There are reports of increased antibiotic resistance rates in Helicobacter pylori strains around the world. The aim of this study was to determine the susceptibility patterns in H. pylori strains isolated in Monterrey, Mexico. We studied 62 strains isolated from the same number of symptomatic adult patients. Metronidazole (Mtz), clarithromycin (Cla), amoxicillin (Amx) and tetracycline (Tet) were tested by the E-test method. We observed that 37.1% of the strains were resistant to Mtz (MIC > or = 8 mg/L), and 8.1% to Cla (MIC > or = 8 mg/L), but we did not observe resistance to Amx (MIC > or = 2 mg/L) or Tet (MIC > or = 4 mg/L). In northeastern Mexico, the percentage of resistant strains was similar to that observed in developed countries. These results confirm that it is necessary to evaluate the susceptibility patterns of H. pylori strains by geographic area