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Chronic Periodontal Disease, Periodontal Pathogen Colonization, and an Increased Risk of Precancerous Gastric Lesions

Sun, Jinghua; Zhou, Min; Salazar, Christian R; Hays, Rosemary; Bedi, Sukhleen; Chen, Yu; Li, Yihong
BACKGROUND: The present study assessed the association between periodontal pathogen colonization and the potential risk of developing precancerous lesions of gastric cancer (PLGC) in a clinical setting. METHODS: The present study included 35 newly diagnosed patients with PLGC and 70 age-matched individuals without PLGC. A full-mouth intra-oral examination was performed to assess the periodontal conditions. Stimulated whole saliva and pooled plaque samples were collected to evaluate colonization by Porphyromonas gingivalis, Treponema denticola, Tannerella forsythia and Actinobacillus actinomycetemcomitans and to characterize the oral microbial diversity in the saliva and dental plaque. RESULTS: Compared with the control group, the patients with PLGC experienced a higher prevalence of bleeding on probing (BOP; 31.5% vs. 22.4%, P < 0.05), higher levels of T. denticola (P < 0.01) and A. actinomycetemcomitans (P <0.01), and less bacterial diversity in their saliva (P < 0.01). The final multivariate logistic regression model comprising all key socio-demographic characteristics, oral health behavioral factors and periodontal assessments revealed that elevated colonization with periodontal pathogens, specifically T. forsythia, T. denticola, and A. actinomycetemcomitans, decreased bacterial diversity in the dental plaque, and not flossing teeth regularly were significant predictors of an increased risk of PLGC (P = 0.022). CONCLUSION: The findings of the present study provide new evidence suggesting that periodontal pathogen burdens and bacterial diversity in the oral cavity are important factors contributing to a potential increased risk of developing precancerous gastric lesions.
PMID: 28671506
ISSN: 1943-3670
CID: 2617042

Midgut bacterial communities in the giant Asian honeybee (Apisdorsata) across four developmental stages: a comparative study

Saraithong, Prakaimuk; Li, Yihong; Saenphet, Kanokporn; Chen, Zhou; Chantawannakul, Panuwan
Bacterial communities are known to play important roles during the developmental stages of insects, but current knowledge of bacteria associated with the midgut of Apisdorsata,the giant Asian honeybee, is limited.Using polymerase chain reaction-denaturing gradient gel electrophoresis analysis (PCR-DGGE) and 16S rRNA sequencing, the aim of this study was to determine the dynamics of bacterialcommunity structure across four A. dorsata life stages in different geographical locations. The results reveal that bacterial diversity increased as the bee progressed through larval stage to newly emerged worker and oldworker. However, in the pupal stage, no bands identified as bacteria couldbe observed. Overall, twobacterial phyla (Proteobacteria and Firmicutes) and four classes (Alphaproteobacteria, Betaproteobacteria, Gammaproteobacteria, and Bacilli) were identified, but the frequency varied among the different stages and locations. The classes of Gammaproteobacteria and Bacilli dominated among larval, newly emerged worker and old worker developmental stages
PMID: 26299408
ISSN: 1744-7917
CID: 1742322

Streptococcus mutans Displays Altered Stress Responses While Enhancing Biofilm Formation by Lactobacillus casei in Mixed-Species Consortium

Wen, Zezhang T; Liao, Sumei; Bitoun, Jacob P; De, Arpan; Jorgensen, Ashton; Feng, Shihai; Xu, Xiaoming; Chain, Patrick S G; Caufield, Page W; Koo, Hyun; Li, Yihong
Like Streptococcus mutans, lactobacilli are commonly isolated from carious sites, although their exact role in caries development remains unclear. This study used mixed-species models to analyze biofilm formation by major groups of oral lactobacilli, including L. casei, L. fermentum, L. rhamnosus, L. salivarius ssp. salivarius, and L. gasseri. The results showed that lactobacilli did not form good biofilms when grown alone, although differences existed between different species. When grown together with S. mutans, biofilm formation by L. gasseri and L. rhamnosus was increased by 2-log (P < 0.001), while biofilms by L. fermentum reduced by >1-log (P < 0.001). L. casei enhanced biofilm formation by ~2-log when grown with S. mutans wild-type, but no such effects were observed with S. mutans deficient of glucosyltransferase GtfB and adhesin P1. Both S. mutans and L. casei in dual-species enhanced resistance to acid killing with increases of survival rate by >1-log (P < 0.001), but drastically reduced the survival rates following exposure to hydrogen peroxide (P < 0.001), as compared to the respective mono-species cultures. When analyzed by RNA-seq, more than 134 genes were identified in S. mutans in dual-species with L. casei as either up- or down-regulated when compared to those grown alone. The up-regulated genes include those for superoxide dismutase, NADH oxidase, and members of the mutanobactin biosynthesis cluster. Among the down-regulated genes were those for GtfB and alternative sigma factor SigX. These results further suggest that interactions between S. mutans and oral lactobacilli are species-specific and may have significant impact on cariogenic potential of the community.
PMCID:5742344
PMID: 29326887
ISSN: 2235-2988
CID: 2905442

Host-Microbiome Cross-talk in Oral Mucositis

Vasconcelos, R M; Sanfilippo, N; Paster, B J; Kerr, A R; Li, Y; Ramalho, L; Queiroz, E L; Smith, B; Sonis, S T; Corby, P M
Oral mucositis (OM) is among the most common, painful, and debilitating toxicities of cancer regimen-related treatment, resulting in the formation of ulcers, which are susceptible to increased colonization of microorganisms. Novel discoveries in OM have focused on understanding the host-microbial interactions, because current pathways have shown that major virulence factors from microorganisms have the potential to contribute to the development of OM and may even prolong the existence of already established ulcerations, affecting tissue healing. Additional comprehensive and disciplined clinical investigation is needed to carefully characterize the relationship between the clinical trajectory of OM, the local levels of inflammatory changes (both clinical and molecular), and the ebb and flow of the oral microbiota. Answering such questions will increase our knowledge of the mechanisms engaged by the oral immune system in response to mucositis, facilitating their translation into novel therapeutic approaches. In doing so, directed clinical strategies can be developed that specifically target those times and tissues that are most susceptible to intervention.
PMCID:4914867
PMID: 27053118
ISSN: 1544-0591
CID: 2066372

Tongue Coating and the Salivary Microbial Communities Vary in Children with Halitosis

Ren, Wen; Xun, Zhe; Wang, Zicheng; Zhang, Qun; Liu, Xuenan; Zheng, Hui; Zhang, Qian; Zhang, Yifei; Zhang, Linshuang; Wu, Chunyan; Zheng, Shuguo; Qin, Nan; Ehrlich, S Dusko; Li, Yihong; He, Xuesong; Xu, Tao; Chen, Ting; Chen, Feng
Halitosis is a common symptom mainly caused by microbial activities in the oral cavity. Here, we used 16S rRNA gene pyrosequencing and metagenomic sequencing to examine oral microbial compositions and their functional variations in children with halitosis. We found that the tongue coating of subjects with halitosis had greater bacterial richness than those of healthy subjects. The relative abundance and prevalence of Leptotrichia wadei and Peptostreptococcus stomatis were higher in tongue coating samples from children with halitosis than those from children without halitosis; Prevotella shahii had higher relative abundance and prevalence in saliva samples from children with halitosis. We present the first comprehensive evaluation of the co-occurrence networks of saliva and tongue coating communities under healthy and halitosis conditions, and investigated patterns of significant differences between these communities. Moreover, we observed that bacterial genes associated with responses to infectious diseases and terpenoid and polyketide metabolism were enriched in subjects with halitosis, but not in healthy subjects. Hydrogen sulphide (H2S)-related metabolic pathways suggested that there was higher microbial production and less usage of H2S in subjects with halitosis. Thus, the mechanism of halitosis was implied for the first time via metagenomic sequencing.
PMCID:4832241
PMID: 27080513
ISSN: 2045-2322
CID: 2078572

Modulation of the orodigestive tract microbiome in HIV-infected patients

Saxena, D; Li, Y; Devota, A; Pushalkar, S; Abrams, W; Barber, C; Corby, P; Poles, M; Phelan, J; Malamud, D
More than 37 million people are living with human immunodeficiency virus 1 (HIV), and more people than ever received lifesaving antiretroviral therapy worldwide. HIV-1 infection disrupts the intestinal immune system, leading to microbial translocation and systemic immune activation. We investigated the impact of HIV-1 infection on the GI microbiome and its association with host immune activation. The data indicated that the microbiome was different in HIV-positive and HIV-negative individuals. The initial sequence analysis of saliva indicated that there were major differences in the phyla of Bacteroidetes, Firmicutes, Proteobacteria, and TM7. Phylum Tenericutes was only seen in HIV-positive saliva. At the family level, we identified differences in Streptococcacea, Prevotellaceae, Porphyromonadaceae, and Neisseriaceae, whereas data from various sites in GI tract indicated that Prevotella melaninigencia, Fusobacterium necrophorum, Burkholderia, Bradyrhizobium, Ralstonia, and Eubacterium biforme were predominant but differentially present at various sites. Furthermore, there was a decrease in seven proteins associated with the alternative complement pathway and an increase in 6 proteins associated with the lectin and classical complement pathways. The correlation with a shift in complement pathways suggests that compromised immunity could be responsible for the observed dysbiosis in the GI microbiome.
PMID: 27109275
ISSN: 1601-0825
CID: 2091922

Initial acquisition of S. mutans, S. sobrinus, an S. sanguinis by infants

Chapter by: Li, Yihong; Chen, Zhou; Zhou, Qiong; Dasanayake, Ananda P
in: RSE : Research Scholarship Expo by
[S.l. : NYU College of Dentistry], 2016
pp. 045-045
ISBN: n/a
CID: 2889792

Streptococcus mutans and Streptococcus sobrinus colonization and caries experience in 3- and 5-year-old Thai children

Saraithong, P; Pattanaporn, K; Chen, Z; Khongkhunthian, S; Laohapensang, P; Chhun, N; Pattanaporn, W; Gaw, H Y; Li, Y
OBJECTIVES: The aim of this study was to examine the colonization of Streptococcus mutans and Streptococcus sobrinus in supra-gingival plaque samples and to determine their correlation with the prevalence of early childhood caries (ECC) in Thai children. MATERIALS AND METHODS: A total of 344 Thai children, ages 3 and 5 years, were invited to participate in this study. Caries status of the children was examined. Supra-gingival plaque samples were collected. Quantitative real-time PCR was performed to evaluate DNA levels of S. mutans and S. sobrinus. RESULTS: Eighty-five percent of the children were colonized by S. mutans and 50.9 % of them were colonized by S. sobrinus. The prevalence of ECC was 43.8 % and 56.2 % among 3- and 5-year-old children, respectively, and was significantly associated with the presence of S. mutans and S. sobrinus. The severity of ECC was significantly correlated with increased DNA levels of the two bacteria. Children who were positive for S. mutans and S. sobrinus (Sm+/Sb+) were 8 times or 44 times more likely to experience ECC than children who were Sm-/Sb + or were Sm-/Sb-. CONCLUSIONS: The study evidence further suggest that children colonized by both S. mutans and S. sobrinus are at the higher risk for ECC. CLINICAL RELEVANCE: Molecular-based qPCR can be used to detect and quantify S. mutans and S. sobrinus colonization for epidemiological and clinical studies for ECC risk assessment.
PMCID:4886470
PMID: 25753978
ISSN: 1432-6981
CID: 1495962

Bacterial community structure in Apis florea larvae analyzed by denaturing gradient gel electrophoresis and 16S rRNA gene sequencing

Saraithong, Prakaimuk; Li, Yihong; Saenphet, Kanokporn; Chen, Zhou; Chantawannakul, Panuwan
This study characterizes the colonization and composition of bacterial flora in dwarf Asian honeybee (Apis florea) larvae and compares bacterial diversity and distribution among different sampling locations. A. florea larvae were collected from 3 locations in Chiang Mai province, Thailand. Bacterial DNA was extracted from each larva using the phenol-chloroform method. Denaturing gradient gel electrophoresis was performed, and the dominant bands were excised from the gels, cloned, and sequenced for bacterial species identification. The result revealed similarities of bacterial community profiles in each individual colony, but differences between colonies from the same and different locations. A. florea larvae harbor bacteria belonging to 2 phyla (Firmicutes and Proteobacteria), 5 classes (Alphaproteobacteria, Betaproteobacteria, Gammaproteobacteria, Bacilli, and Clostridia), 6 genera (Clostridium, Gilliamella, Melissococcus, Lactobacillus, Saccharibacter, and Snodgrassella), and an unknown genus from uncultured bacterial species. The classes with the highest abundance of bacteria were Alphaproteobacteria (34%), Bacilli (25%), Betaproteobacteria (11%), Gammaproteobacteria (10%), and Clostridia (8%), respectively. Similarly, uncultured bacterial species were identified (12%). Environmental bacterial species, such as Saccharibacter floricola, were also found. This is the first study in which sequences closely related to Melissococcus plutonius, the causal pathogen responsible for European foulbrood, have been identified in Thai A. florea larvae.
PMID: 25393530
ISSN: 1744-7917
CID: 1773232

Oral Lactobacilli and Dental Caries: A Model for Niche Adaptation in Humans

Caufield, P W; Schon, C N; Saraithong, P; Li, Y; Argimon, S
Lactobacilli have been associated with dental caries for over a century. Here, we review the pertinent literature along with findings from our own study to formulate a working hypothesis about the natural history and role of lactobacilli. Unlike most indigenous microbes that stably colonize a host, lactobacilli appear to be planktonic, opportunistic settlers that can gather and multiply only in certain restrictive niches of the host, at least within the oral cavity. We postulate that the following essential requirements are necessary for sustained colonization of lactobacilli in humans: 1) a stagnant, retentive niche that is mostly anaerobic; 2) a low pH milieu; and 3) ready access to carbohydrates. Three sites on the human body meet these specifications: caries lesions, the stomach, and the vagina. Only a handful of Lactobacillus species is found in caries lesions, but they are largely absent in caries-free children. Lactobacilli present in caries lesions represent both a major contributor to caries progression and a major reservoir to the gastrointestinal (GI) tract. We extend the assertion from other investigators that lactobacilli found in the GI tract originate in the oral cavity by proposing that lactobacilli in the oral cavity arise from caries lesions. This, in turn, leads us to reflect on the health implications of the lactobacilli in the mouth and downstream GI and to ponder whether these or any of the Lactobacillus species are truly indigenous to the human GI tract or the oral cavity.
PMCID:4547204
PMID: 25758458
ISSN: 0022-0345
CID: 1495952