Dysbiosis, Recurrent Bacterial Vaginosis and the Vaginal Microbiome

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Project Summary/Abstract: Disrupted or “dysbiotic” vaginal microbiota, as epitomized by the clinical syndrome of bacterial vaginosis (BV), can result in severe recurrent symptoms despite antibiotic therapy, as well as serious reproductive consequences including preterm labor and the acquisition and transmission of sexually transmitted infections. New molecular techniques are enabling a more sophisticated understanding of the complex structure of vaginal microbial communities, while studies from the nascent field of metabolomics suggest that the functional output of these microbiota may be a key factor in the pathogenesis of dysbiosis. Hormonal contraception (HC) has been shown in epidemiologic studies to decrease the risk of incident and recurrent BV in some, but not all women. Preliminary data suggests that HC stabilizes and shifts the microbiota away from the low-lactobacilli, mixed anaerobe-predominant communities characteristic of BV. As such, it may hold promise as a way to ameliorate dysbiosis and treat recurrent BV in selected patients. However, despite over 50 years of widespread use, our understanding of the impact of HC on the structure of vaginal communities in asymptomatic women is incomplete, and the impact of HC on the function of vaginal communities in these women is not known. Additionally, the impact of HC on the structure and function of the vaginal microbiota in women with recurrent BV is unknown. This proposal seeks to elucidate these questions through 3 aims: 1) To evaluate the impact of HC on the structure of the vaginal microbiota in asymptomatic women as measured by absolute bacterial counts of Lactobacillus species, (in particular L. iners), and other selected anaerobes in vaginal microbial communities, 2) To determine the impact of HC on the function of the vaginal microbiota in asymptomatic women as measured by the production of lactic acid isomers and biogenic amines, and 3) To evaluate the impact of HC on the structure and function of the vaginal microbiota in a small pilot cohort of women with recurrent BV. Aims 1 and 2 will be nested within an existing cohort study, the Hormonal Contraception Longitudinal Study. For aim 3, the PI will recruit a small pilot cohort for an observational study of women with recurrent BV starting on HC. Through formal didactics and structured mentorship from a team which comprises experts in genitourinary infections, metagenomics, and advanced analytics, the PI will develop a unique analytic skill set, including knowledge of the R statistical package, longitudinal data analysis, multi-level modeling, principle component analysis and hierarchical clustering analysis, as well as experience in patient recruitment and clinical research. This will enable her to achieve the long-term goal of becoming an independent clinical investigator who will utilize the powerful new tools of metagenomics and metabolomics to design and lead interventions to improve clinical outcomes in women.