The vaginal microbiome of healthy, bacterial vaginosis and Chlamydia trachomatis-infected women

Backgrounds: The vaginal microbiota of healthy women is generally dominated by Lactobacillus spp., which are known to protect the female genital tract from microbial dysbiosis and pathogen overgrowth. Alterations of the vaginal microbiota composition are found in bacterial vaginosis (BV). Lactobacilli have also been hypothesized to protect women from sexually transmitted diseases, including Chlamydia trachomatis (CT) infection, which represents the most common bacterial sexually transmitted infection worldwide. Both BV and CT infection can lead to severe sequelae and complications, including preterm labor and delivery, and tubal infertility. Objectives: The aim of this study is to analyse the composition of the endogenous microbiota and the metabolic profiles of the vaginal niche in three different conditions: healthy, BV and CT infection. Methods: Vaginal swabs were obtained from 66 women, belonging to three groups (healthy, BV and CT-infected women). The microbial composition of the samples was determined by using a microarray-based tool (VaginArray) targeting the most representative bacterial groups of the vaginal ecosystem, together with a quantitative real-time PCR for Gardnerella vaginalis. The metabolic profiles of the vaginal specimens were assessed by 1H-NMR. Conclusions: From our results the microbial signature of BV-affected women is clearly different from that found in healthy subjects, CT-infected women are characterized by a microbiota similar to the healthy condition. The metabolomics approach evidenced that BV-samples are characterized by significant variations in organic acids, aminoacids, short chain fatty acids concentrations. CT-infected women metabolome resembles that of healthy subjects, nevertheless significant variations in biogenic amines content were underlined.