Mapping cervical microbiome diversity and inflammatory milieu and its perturbation in asymptomatic bacterial vaginosis and Candida infections: Insights from a community clinic in Mumbai

PURPOSE: The interplay between the local microbiome and inflammatory environment is crucial in modulating the immune response. This research addresses the paucity of studies in the Indian context by mapping the cervical microbiome and associated inflammatory milieu in 43 apparently healthy women and evaluating its perturbations with various asymptomatic vaginal infections. METHODS: Cervical microbiome was mapped for forty three participants, aged 18-45, who were enrolled from a community clinic as a part of longitudinal contraceptive study from October 2021 to September 2023. Sociodemographic data, clinical history, and cervical and cervicovaginal lavage specimens were collected. Microbiome analysis involved nanopore sequencing of the entire 16S rRNA region amplicon, while cytokine assessment in cervicovaginal lavage specimens utilized multiplex immunoassays. RESULTS: Firmicutes, Bacteroidetes, Actinobacteria, Proteobacteria, and Fusobacteria appeared as dominant phyla with 32.55% having asymptomatic bacterial vaginosis (BV),16.27% asymptomatic Candida, and 13.95% coinfections. The cervical microbiome was dominated by Lactobacillus iners (45.69%), followed by Lactobacillus helveticus (6.53%) and Lactobacillus reuteri (5.86%). Women with BV exhibited an increased abundance of Prevotella and Streptococcus, while Candida infections were associated with elevated Atopobium and Collinsella species. Pro-inflammatory cytokines (IL-1β, IL-6, TNF-α, IL-8) showed variable levels, with Lactobacillus positively correlating with the regulatory cytokine TNF-α in in Candida infections. In BV Lactobacillus species such as L. agilus, L.iners and L. salivarius showed positive correlation with TNF-α. Additionally, Lactobacillus manihotivoranswas negatively associated with IL-1β, while Lactobacillus brevis and Lactobacilluszeae showed negative correlations with IL-8. CONCLUSION: This study maps the cervical microbiome and cytokine profile of healthy Indian women and demonstrates that asymptomatic bacterial vaginosis and Candida infections induces variations, highlighting the complex host-microbe interactions that govern vaginal health.