Lactobacillus iners-dominated vaginal microbiota is associated with increased susceptibility to Chlamydia trachomatis infection in Dutch women: a case-control study

INTRODUCTION

This prospective study aimed to study the composition and structure of the vaginal microbiota prior to Chlamydia trachomatis infection.

METHODS

A nested case-control study was performed in 122 women, half of which acquired C. trachomatis within a year after their first visit. At the first visit, the composition and structure of vaginal microbial communities were analysed using 16S rRNA sequencing in the context of the sociodemographic and sexual risk behaviour information using logistic regression.

RESULTS

Five vaginal community state types (CSTs) were identified. Four CSTs were dominated by Lactobacillus spp., of which L. crispatus (37%) and L. iners (33%) were the most common. One CST was characterised by the absence of Lactobacillus spp. (25%) and the presence of an array of strict and facultative anaerobes. Multivariate logistic regression analysis revealed that women with a L. iners-dominated CST had an increased risk of C. trachomatis infection (p=0.04; OR: 2.6, 95% CI 1.0 to 6.6).

CONCLUSIONS

The distribution of CSTs dominated by Lactobacillus spp. agreed with previous studies. However, the frequency of dysbiosis among Caucasian women was relatively high (24%). Having vaginal microbiota dominated by L. iners was associated with an increased risk for C. trachomatis infection. Therefore, we hypothesise that specific signatures of vaginal microbiota are indicative of increased host predisposition to acquiring STIs.

The implausible "in vivo" role of hydrogen peroxide as an antimicrobial factor produced by vaginal microbiota

In the cervicovaginal environment, the production of hydrogen peroxide (H₂O₂) by vaginal Lactobacillus spp. is often mentioned as a critical factor to the in vivo vaginal microbiota antimicrobial properties. We present several lines of evidence that support the implausibility of H₂O₂ as an "in vivo" contributor to the cervicovaginal milieu antimicrobial properties. An alternative explanation is proposed, supported by previous reports ascribing protective and antimicrobial properties to other factors produced by Lactobacillus spp. capable of generating H₂O₂. Under this proposal, lactic acid rather than H₂O₂ plays an important role in the antimicrobial properties of protective vaginal Lactobacillus spp. We hope this commentary will help future research focus on more plausible mechanisms by which vaginal Lactobacillus spp. exert their antimicrobial and beneficial properties, and which have in vivo and translational relevance.

Associations between sexual habits, menstrual hygiene practices, demographics and the vaginal microbiome as revealed by Bayesian network analysis

The vaginal microbiome plays an influential role in several disease states in reproductive age women, including bacterial vaginosis (BV). While demographic characteristics are associated with differences in vaginal microbiome community structure, little is known about the influence of sexual and hygiene habits. Furthermore, associations between the vaginal microbiome and risk symptoms of bacterial vaginosis have not been fully elucidated. Using Bayesian network (BN) analysis of 16S rRNA gene sequence results, demographic and extensive questionnaire data, we describe both novel and previously documented associations between habits of women and their vaginal microbiome. The BN analysis approach shows promise in uncovering complex associations between disparate data types. Our findings based on this approach support published associations between specific microbiome members (e.g., Eggerthella, Gardnerella, Dialister, Sneathia and Ruminococcaceae), the Nugent score (a BV diagnostic) and vaginal pH (a risk symptom of BV). Additionally, we found that several microbiome members were directly connected to other risk symptoms of BV (such as vaginal discharge, odor, itch, irritation, and yeast infection) including L. jensenii, Corynebacteria, and Proteobacteria. No direct connections were found between the Nugent Score and risk symptoms of BV other than pH, indicating that the Nugent Score may not be the most useful criteria for assessment of clinical BV. We also found that demographics (i.e., age, ethnicity, previous pregnancy) were associated with the presence/absence of specific vaginal microbes. The resulting BN revealed several as-yet undocumented associations between birth control usage, menstrual hygiene practices and specific microbiome members. Many of these complex relationships were not identified using common analytical methods, i.e., ordination and PERMANOVA. While these associations require confirmatory follow-up study, our findings strongly suggest that future studies of the vaginal microbiome and vaginal pathologies should include detailed surveys of participants' sanitary, sexual and birth control habits, as these can act as confounders in the relationship between the microbiome and disease. Although the BN approach is powerful in revealing complex associations within multidimensional datasets, the need in some cases to discretize the data for use in BN analysis can result in loss of information. Future research is required to alleviate such limitations in constructing BN networks. Large sample sizes are also required in order to allow for the incorporation of a large number of variables (nodes) into the BN, particularly when studying associations between metadata and the microbiome. We believe that this approach is of great value, complementing other methods, to further our understanding of complex associations characteristic of microbiome research.

Vaginal microbiota composition and association with prevalent Chlamydia trachomatis infection: a cross-sectional study of young women attending a STI clinic in France

Objectives

New molecular techniques have allowed describing groups of bacterial communities in the vagina (community state types (CST)) that could play an important role in Chlamydia trachomatis (CT) infection. Our aim was to describe the distribution of CST in a population of young women in France.

Methods

A cross-sectional study was carried out in June 2015 among anonymous young women attending a STI clinic in Bordeaux, France. Participants provided a vaginal sample for CT screening and sociodemographic data. CT was diagnosed using the Aptima-combo 2 transcription-mediated-amplification assay. Vaginal microbiota composition was characterised using 16S rRNA gene amplicon sequencing.

Results

Microbiota composition and CT status were available for 132 women. CST dominated by Lactobacillus crispatus (CST-I), L. iners (CST-III) and a diversity of anaerobes (CST-IV) represented 37.1%, 38.6% and 22.0% of the sample, respectively. Twenty-one out of 132 women were CT positive. Proportions of CT-positive women were higher for samples belonging to CST-III (21.6%) and CST-IV (17.2%) than to CST-I (8.2%).

Conclusions

Five CST were found in 132 young women from a STI clinic in France. These CSTs were not significantly associated with CT but higher proportions of CT-positive women were found in CST-III and CST-IV, consistent with a previous study in the Netherlands. Though our study lacked statistical power and was cross-sectional, it is a necessary first step to understand the structure of the vaginal microbiota in French women with or without infection before performing in-depth longitudinal studies.

Cigarette smoking is associated with an altered vaginal tract metabolomic profile

Cigarette smoking has been associated with both the diagnosis of bacterial vaginosis (BV) and a vaginal microbiota lacking protective Lactobacillus spp. As the mechanism linking smoking with vaginal microbiota and BV is unclear, we sought to compare the vaginal metabolomes of smokers and non-smokers (17 smokers/19 non-smokers). Metabolomic profiles were determined by gas and liquid chromatography mass spectrometry in a cross-sectional study. Analysis of the 16S rRNA gene populations revealed samples clustered into three community state types (CSTs) ---- CST-I (L. crispatus-dominated), CST-III (L. iners-dominated) or CST-IV (low-Lactobacillus). We identified 607 metabolites, including 12 that differed significantly (q-value < 0.05) between smokers and non-smokers. Nicotine, and the breakdown metabolites cotinine and hydroxycotinine were substantially higher in smokers, as expected. Among women categorized to CST-IV, biogenic amines, including agmatine, cadaverine, putrescine, tryptamine and tyramine were substantially higher in smokers, while dipeptides were lower in smokers. These biogenic amines are known to affect the virulence of infective pathogens and contribute to vaginal malodor. Our data suggest that cigarette smoking is associated with differences in important vaginal metabolites, and women who smoke, and particularly women who are also depauperate for Lactobacillus spp., may have increased susceptibilities to urogenital infections and increased malodor.

Human oral microbiome and prospective risk for pancreatic cancer: a population-based nested case-control study

OBJECTIVE

A history of periodontal disease and the presence of circulating antibodies to selected oral pathogens have been associated with increased risk of pancreatic cancer; however, direct relationships of oral microbes with pancreatic cancer have not been evaluated in prospective studies. We examine the relationship of oral microbiota with subsequent risk of pancreatic cancer in a large nested case-control study.

DESIGN

We selected 361 incident adenocarcinoma of pancreas and 371 matched controls from two prospective cohort studies, the American Cancer Society Cancer Prevention Study II and the National Cancer Institute Prostate, Lung, Colorectal and Ovarian Cancer Screening Trial. From pre-diagnostic oral wash samples, we characterised the composition of the oral microbiota using bacterial 16S ribosomal RNA (16S rRNA) gene sequencing. The associations between oral microbiota and risk of pancreatic cancer, controlling for the random effect of cohorts and other covariates, were examined using traditional and L1-penalised least absolute shrinkage and selection operator logistic regression.

RESULTS

Carriage of oral pathogens, Porphyromonas gingivalis and Aggregatibacter actinomycetemcomitans, were associated with higher risk of pancreatic cancer (adjusted OR for presence vs absence=1.60 and 95% CI 1.15 to 2.22; OR=2.20 and 95% CI 1.16 to 4.18, respectively). Phylum Fusobacteria and its genus Leptotrichia were associated with decreased pancreatic cancer risk (OR per per cent increase of relative abundance=0.94 and 95% CI 0.89 to 0.99; OR=0.87 and 95% CI 0.79 to 0.95, respectively). Risks related to these phylotypes remained after exclusion of cases that developed within 2 years of sample collection, reducing the likelihood of reverse causation in this prospective study.

CONCLUSIONS

This study provides supportive evidence that oral microbiota may play a role in the aetiology of pancreatic cancer.

Clinical Relevance of Gastrointestinal Microbiota During Pregnancy: A Primer for Nurses

Emerging evidence about the human microbiome, a collective term for all the microorganisms living in and on the human body, consistently demonstrates the critical influence it has on host physiology and disease risk. The microbiota in the gastrointestinal (GI) tract has the most significant and far-reaching effect on human physiology. The maternal GI microbiota can decrease the risk of adverse pregnancy outcomes by modulating energy extraction, glucose metabolism, vitamin production, and host immunity essential for optimal maternal and neonatal health. Moreover, the maternal GI microbiota is thought to influence colonization of the fetus and neonate that may predispose them to different health trajectories. This article provides a basic understanding about the influence of the structure of the maternal GI microbiota, the fundamental role it plays during pregnancy, and the factors that influence the structure, and subsequently function, of the GI microbiota in the general and pregnant population. While only a small number of studies have examined this topic during pregnancy, the preponderance of the evidence supports the need to clarify baseline structure and function of GI microbiota and its associations with pregnancy outcomes. In addition, the results from the studies conducted in the general population can be extrapolated to pregnancy in many cases. This knowledge is essential for clinicians who need to understand the implications of the microbiota for disease and wellness in order to address the care factors that may adversely influence the GI microbiota during pregnancy.

Does Active Oral Sex Contribute to Female Infertility?

Based on recent, historical, and circumstantial evidence, we present a multifactorial hypothesis that has potential direct implications on the epidemiology and management of chlamydial infection and disease in humans. We propose that (1) like its veterinary relatives, the oculogenital pathogen Chlamydia trachomatis evolved as a commensal organism of the human gastrointestinal (GI) tract primarily transmissible via the fecal-oral route; (2) in the modern era, C. trachomatis causes "opportunistic" infection at non-GI sites under conditions driven by improved sanitation/hygiene and reduced fecal-oral transmission; and (3) the rise in the practice of oral sex is contributing to the increased prevalence of C. trachomatis in the human GI tract. Infectious organisms produced in the GI tract and reaching the rectum may then chronically contaminate and infect the female urogenital tract, thereby potentially contributing to the most serious sequelae of chlamydial infection in women: pelvic inflammatory disease, ectopic pregnancy, and tubal factor infertility.

Early screening for Chlamydia trachomatis in young women for primary prevention of pelvic inflammatory disease (i-Predict): study protocol for a randomised controlled trial

Background

Genital infection with Chlamydia trachomatis (Ct) is the most common bacterial sexually transmitted infection, especially among young women. Mostly asymptomatic, it can lead, if untreated, to pelvic inflammatory disease (PID), tubal factor infertility and ectopic pregnancy. Recent data suggest that Ct infections are not controlled in France and in Europe. The effectiveness of a systematic strategy for Ct screening in under-25 women remains controversial. The main objective of the i-Predict trial (Prevention of Diseases Induced by Chlamydia trachomatis) is to determine whether early screening and treatment of 18- to-24-year-old women for genital Ct infection reduces the incidence of PID over 24 months.

Methods/design

This is a randomised prevention trial including 4000 eighteen- to twenty-four-year-old sexually active female students enrolled at five universities. The participants will provide a self-collected vaginal swab sample and fill in an electronic questionnaire at baseline and at 6, 12 and 18 months after recruitment. Vaginal swabs in the intervention arm will be analysed immediately for Ct positivity, and participants will be referred for treatment if they have a positive test result. Vaginal swabs from the control arm will be analysed at the end of the study. All visits to general practitioners, gynaecologists or gynaecology emergency departments for pelvic pain or other gynaecological symptoms will be recorded to evaluate the incidence of PID, and all participants will attend a final visit in a hospital gynaecology department. The primary endpoint measure will be the incidence of PID over 24 months. The outcome status (confirmed, probable or no PID) will be assessed by two independent experts blinded to group assignment and Ct status.

Discussion

This trial is expected to largely contribute to the development of recommendations for Ct screening in young women in France to prevent PID and related complications. It is part of a comprehensive approach to gathering data to facilitate decision-making regarding optimal strategies for Ct infection control. The control group of this randomised trial, following current recommendations, will allow better documentation of the natural history of Ct infection, a prerequisite to evaluating the impact of Ct screening. Characterisation of host immunogenetics will also allow identification of women at risk for complications.

Trial registration

ClinicalTrials.gov, NCT02904811. Registered on September 14, 2016.

World Health Organisation International Clinical Trials Registry, NCT02904811.

AOM, 15-0063 and P150950. Registered on September 26, 2016. A completed Standard Protocol Items : Recommendations for International Trials (SPIRIT) Checklist is available in additional file 1.

Electronic supplementary material

The online version of this article (doi:10.1186/s13063-017-2211-1) contains supplementary material, which is available to authorized users.

Role of Molecular Biology in Diagnosis and Characterization of Vulvo-Vaginitis in Clinical Practice

The diagnosis of vulvo-vaginal complaints has always been enigmatic in obstetrics and gynecology. Patients with clear, pathognomonic symptoms end up with a proper diagnosis and treatment most of the time, but unfortunately we are now living in a world where women reach out to the Internet and readily get all information as to which disease their symptoms correspond to and also find the appropriate treatment "over-the-counter." Because of this trend, we as specialists are increasingly confronted with patients with complex and combined conditions. At the same time, extremely sensitive and accurate diagnostic tools are now being developed at a rapid pace, allowing the physicians to diagnose vulvo-vaginal disease with a substantially increased precision. Moreover, many of these molecular biology (MB)-based tests have become so common and affordable that self-sampling and self-testing are no longer utopia. On the other hand, too much information that is too readily available and that is too affordable also encompasses pitfalls, leading to gross overtreatment and psychological burden. As experienced caregivers, we should supervise these evolutions, define their place and proper use as diagnostic tools, utilize their potential as ad hoc tools to follow-up treatment efficacy and guide how such tools can be used for responsible self-testing. In the present paper, responding to the need for appropriate, quality assured and accessible tests for vulvo-vaginitis and the huge potential delivered by the rapidly developing MB methods, we recommend the need for a broad and regular discussion forum, composed of both clinical and technical experts and opinion makers, in order to match the needs with the huge opportunities and ideally combine the initiatives and forces into the same direction. This forum should then translate conceived strategies into regularly updated, evidence-based national and international guidelines.

Group B Streptococcus and the Vaginal Microbiota

Background

Streptococcus agalactiae (group B Streptococcus [GBS]) is an important neonatal pathogen and emerging cause of disease in adults. The major risk factor for neonatal disease is maternal vaginal colonization. However, little is known about the relationship between GBS and vaginal microbiota.

Methods

Vaginal lavage samples from nonpregnant women were tested for GBS, and amplicon-based sequencing targeting the 16S ribosomal RNA V3-V4 region was performed.

Results

Four hundred twenty-eight of 432 samples met the high-quality read threshold. There was no relationship between GBS carriage and demographic characteristics, α-diversity, or overall vaginal microbiota community state type (CST). Within the non-Lactobacillus-dominant CST IV, GBS positive status was significantly more prevalent in CST IV-A than CST IV-B. Significant clustering by GBS status was noted on principal coordinates analysis, and 18 individual taxa were found to be significantly associated with GBS carriage by linear discriminant analysis. After adjusting for race/ethnicity, 4 taxa were positively associated with GBS, and 6 were negatively associated.

Conclusions

Vaginal microbiota CST and α-diversity are not related to GBS status. However, specific microbial taxa are associated with colonization of this important human pathogen, highlighting a potential role for the microbiota in promotion or inhibition of GBS colonization.

Association of HPV infection and clearance with cervicovaginal immunology and the vaginal microbiota

Cervical human papillomavirus (HPV) infection may increase HIV risk. Since other genital infections enhance HIV susceptibility by inducing inflammation, we assessed the impact of HPV infection and clearance on genital immunology and the cervico-vaginal microbiome. Genital samples were collected from 65 women for HPV testing, immune studies and microbiota assessment; repeat HPV testing was performed after 6 months. All participants were HIV-uninfected and free of bacterial STIs. Cytobrush-derived T cell and dendritic cell subsets were assessed by multiparameter flow cytometry. Undiluted cervico-vaginal secretions were used to determine cytokine levels by multiplex ELISA, and to assess bacterial community composition and structure by 16S rRNA gene sequence analysis. Neither HPV infection nor clearance were associated with broad differences in cervical T cell subsets or cytokines, although HPV clearance was associated with increased Langerhans cells and HPV infection with elevated IP-10 and MIG. Individuals with HPV more frequently had a high diversity cervico-vaginal microbiome (community state type IV) and were less likely to have an L. gasseri predominant microbiome. In summary, HPV infection and/or subsequent clearance was not associated with inflammation or altered cervical T cell subsets, but associations with increased Langerhans cells and the composition of the vaginal microbiome warrant further exploration.

Vaginal Candida spp. genomes from women with vulvovaginal candidiasis

Candida albicans is the predominant cause of vulvovaginal candidiasis (VVC). Little is known regarding the genetic diversity of Candida spp. in the vagina or the microvariations in strains over time that may contribute to the development of VVC. This study reports the draft genome sequences of four C. albicans and one C. glabrata strains isolated from women with VVC. An SNP-based whole-genome phylogeny indicates that these isolates are closely related; however, phylogenetic distances between them suggest that there may be genetic adaptations driven by unique host environments. These sequences will facilitate further comparative analyses and ultimately improve our understanding of genetic variation in isolates of Candida spp. that are associated with VVC.

Distinct Effects of the Cervicovaginal Microbiota and Herpes Simplex Type 2 Infection on Female Genital Tract Immunology

Background

Genital inflammation is a key determinant of human immunodeficiency virus (HIV) transmission, and may increase HIV-susceptible target cells and alter epithelial integrity. Several genital conditions that increase HIV risk are more prevalent in African, Caribbean, and other black (ACB) women, including bacterial vaginosis and herpes simplex virus type-2 (HSV-2) infection. Therefore, we assessed the impact of the genital microbiota on mucosal immunology in ACB women and microbiome-HSV-2 interactions.

Methods

Cervicovaginal secretions and endocervical cells were collected by cytobrush and Instead Softcup, respectively. T cells and dendritic cells were assessed by flow cytometry, cytokines by multiplex enzyme-linked immunosorbent assay (ELISA), and the microbiota by 16S ribosomal ribonucleic acid gene sequencing.

Results

The cervicovaginal microbiota of 51 participants were composed of community state types (CSTs) showing diversity (20/51; 39%) or predominated by Lactobacillus iners (22/51; 42%), L. crispatus (7/51; 14%), or L. gasseri (2/51; 4%). High-diversity CSTs and specific bacterial phyla (Gardnerella vaginalis and Prevotella bivia) were strongly associated with cervicovaginal inflammatory cytokines, but not with altered endocervical immune cells. However, cervical CD4+ T-cell number was associated with HSV-2 infection and a distinct cytokine profile.

Conclusions

This suggests that the genital microbiota and HSV-2 infection may influence HIV susceptibility through independent biological mechanisms.

Molecular Characterization of the Human Stomach Microbiota in Gastric Cancer Patients

Helicobacter pylori (Hp) is the primary cause of gastric cancer but we know little of its relative abundance and other microbes in the stomach, especially at the time of gastric cancer diagnosis. Here we characterized the taxonomic and derived functional profiles of gastric microbiota in two different sets of gastric cancer patients, and compared them with microbial profiles in other body sites. Paired non-malignant and tumor tissues were sampled from 160 gastric cancer patients with 80 from China and 80 from Mexico. The 16S rRNA gene V3-V4 region was sequenced using MiSeq platform for taxonomic profiles. PICRUSt was used to predict functional profiles. Human Microbiome Project was used for comparison. We showed that Hp is the most abundant member of gastric microbiota in both Chinese and Mexican samples (51 and 24%, respectively), followed by oral-associated bacteria. Taxonomic (phylum-level) profiles of stomach microbiota resembled oral microbiota, especially when the Helicobacter reads were removed. The functional profiles of stomach microbiota, however, were distinct from those found in other body sites and had higher inter-subject dissimilarity. Gastric microbiota composition did not differ by Hp colonization status or stomach anatomic sites, but did differ between paired non-malignant and tumor tissues in either Chinese or Mexican samples. Our study showed that Hp is the dominant member of the non-malignant gastric tissue microbiota in many gastric cancer patients. Our results provide insights on the gastric microbiota composition and function in gastric cancer patients, which may have important clinical implications.

Abstract 3257: Molecular characterization of the human stomach microbiota in gastric cancer patients

Background Helicobacter pylori (Hp) is the primary cause of gastric cancer but we know little of its relative abundance and other microbes in the stomach, especially at the time of gastric cancer diagnosis. Here we characterized the taxonomic and derived functional profiles of gastric microbiota in 157 non-malignant gastric tissue samples from two different sets of gastric cancer patients, and compared them with microbial profiles of oral, stool, nasal, vagina and skin samples from Human Microbiome Project.

Results We show that Hp is the most abundant member of gastric microbiota in both Chinese and Mexican samples (51% and 24% respectively), followed by the genera commonly seen in the oral microbiota. Taxonomic (phylum) profiles of stomach microbiota largely resembled oral microbiota when the Helicobacter reads were removed. The functional profiles of stomach microbiota, however, were distinct from those found in other body sites and had higher inter-subject dissimilarity. Gastric microbiota composition did not differ by Hp colonization status or stomach anatomic site, but did differ between paired non-malignant and tumor tissues in either Chinese or Mexican samples.

Conclusions Our study is the first to show that Hp is the dominant member of the gastric microbiota in many gastric cancer patients rather than diminished or depleted as traditionally believed. Our results provide insights on the gastric microbiota composition and function in gastric cancer patients, which may have important clinical implications.

Citation Format: Guoqin Yu, Javier Torres, Nan Hu, Rafael Medrano-Guzman, Roberto Herrera-Goepfert, Michael S. Humphrys, Lemin Wang, Chaoyu Wang, Ti Ding, Jacques Ravel, Philip R. Taylor, Christian Abnet, Alisa Goldstein. Molecular characterization of the human stomach microbiota in gastric cancer patients [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 3257. doi:10.1158/1538-7445.AM2017-3257

Abstract 234: Association between fecal microbiome, diet, and colon adenomas and hyperplastic polyps

Background: Colorectal cancer arises from adenomatous and serrated colon polyps that are identifiable with colonoscopy. Generally, a healthy gut is characterized by higher fecal microbiota. We conducted a study to determine whether fecal microbiota composition and structure are associated with colon adenomas and hyperplastic polyps in a set of identical (MZ, monozygotic) twins.

Methods: We enrolled 83 individual twins from the California Twin Program. Of these, 56 (representing 38 twin pairs) had documented past colonoscopy and no gastrointestinal diseases, cancer or recent antibiotic use. Body mass index (BMI) and food frequency information was collected 15 years before stool collection and again at the time of stool collection. The V4 region of the 16S rRNA gene was sequenced using the HiSeq 2500 system. Alpha diversity measures including number of OTU (operational taxonomic units) and Shannon index were calculated for each sample. Mixed ANOVA models with a random effect accounting for twin pair status, were used to examine the association of alpha diversity with polyp status.

Results: Alpha diversity measured by Shannon index and number of unique OTUs was inversely associated with obesity and high beef consumption and positively associated with yogurt consumption. Surprisingly, we found that fecal microbiota alpha diversity was higher in subjects with adenomas and hyperplastic polyps compared to subjects with no polyps. When restricted to subjects with colonoscopy in the 3 years prior to stool collection, differences were stronger and statistically significant (mean OTUs for subjects with adenoma, hyperplastic polyps and no polyps = 908, 850, and 801, respectively; Padenoma vs. no = 0.017, Phyperplastic vs no = 0.007; Plinear trend= 0.018). In order to determine whether diet changes may have played a role, we examined dietary change from food frequency questionnaires collected 15 years apart. We found that subjects with no polyps increased yogurt consumption by 50% over the 15 year period, whereas subjects diagnosed with adenomas and hyperplastic polyps increased their yogurt consumption more (140% and 130%, respectively).

Conclusion: Participants diagnosed with adenomas and hyperplastic polyps had higher fecal microbiota alpha diversity compared to those without polyps. The timing of measurement of fecal microbiota years after colonoscopy obscures the causal relationship between adenoma and fecal microbiome. One possibility is that subjects may have increased their yogurt consumption after a polyp diagnosis, resulting in increased fecal alpha diversity, compared to subjects who were not diagnosed with polyps. Alternatively, polyp removal may alter microbial diversity. A third possibility is that polyp susceptibility is associated with an outgrowth of deleterious bacteria, still present after polyp removal, reflected as increased alpha diversity. Twin comparisons will be presented.

Citation Format: Yang Yu, Joshua Millstein, Amie E. Hwang, Bing Ma, Guoqin Yu, Laura H. Buchanan, Michael Humphreys, Ann S. Hamilton, John Zadnick, Myles G. Cockburn, James Buxbaum, Heinz-Josef Lenz, Thomas M. Mack, Jacques Ravel, Wendy Cozen. Association between fecal microbiome, diet, and colon adenomas and hyperplastic polyps [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 234. doi:10.1158/1538-7445.AM2017-234

Mycoplasma hominis and Mycoplasma genitalium in the Vaginal Microbiota and Persistent High-Risk Human Papillomavirus Infection

Background

Recent studies have suggested that the vaginal microenvironment plays a role in persistence of high-risk human papillomavirus (hrHPV) infection and thus cervical carcinogenesis. Furthermore, it has been shown that some mycoplasmas are efficient methylators and may facilitate carcinogenesis through methylation of hrHPV and cervical somatic cells. We examined associations between prevalence and persistence of Mycoplasma spp. in the vaginal microbiota, and prevalent as well as persistent hrHPV infections.

Methods

We examined 194 Nigerian women who were tested for hrHPV infection using SPF₂₅/LiPA₁₀ and we identified Mycoplasma genitalium and Mycoplasma hominis in their vaginal microbiota established by sequencing the V3–V4 hypervariable regions of the 16S rRNA gene. We defined the prevalence of M. genitalium, M. hominis, and hrHPV based on positive result of baseline tests, while persistence was defined as positive results from two consecutive tests. We used exact logistic regression models to estimate associations between Mycoplasma spp. and hrHPV infections.

Results

The mean (SD) age of the study participants was 38 (8) years, 71% were HIV positive, 30% M. genitalium positive, 45% M. hominis positive, and 40% hrHPV positive at baseline. At follow-up, 16% of the women remained positive for M. genitalium, 30% for M. hominis, and 31% for hrHPV. There was a significant association between persistent M. hominis and persistent hrHPV (OR 8.78, 95% CI 1.49–51.6, p 0.01). Women who were positive for HIV and had persistent M. hominis had threefold increase in the odds of having persistent hrHPV infection (OR 3.28, 95% CI 1.31–8.74, p 0.008), compared to women who were negative for both.

Conclusion

We found significant association between persistent M. hominis in the vaginal microbiota and persistent hrHPV in this study, but we could not rule out reverse causation. Our findings need to be replicated in larger, longitudinal studies and if confirmed, could have important diagnostic and therapeutic implications.