Microbiota and inflammatory factor profiles in different stages of bacterial vaginosis formation and recurrence

Introduction. Bacterial vaginosis (BV) is a common gynaecological disorder characterized by an imbalance in the vaginal microbiota, leading to increased risk of infection and recurrence.Hypothesis/Gap statement. Although the role of microbiota dysbiosis in BV is established, the dynamic changes in microbial communities and inflammatory factors during BV formation and recurrence, as well as reliable biomarkers for predicting recurrence, remain inadequately explored.Aim. This study aimed to systematically analyse the changes in vaginal microbiota and inflammatory factors during different stages of BV formation and recurrence, and to identify potential biomarkers for predicting BV recurrence.Methodology. Vaginal swab samples were collected from 135 women, including 55 BV patients, 50 intermediate BV (IBV) patients and 30 healthy controls. Twenty-six recurrent BV (Re-BV) samples were obtained within 1 year after treatment. 16S rRNA gene sequencing was performed to profile the vaginal microbiota, and ELISA was used to measure IL-6, IL-10 and IL-1β levels. Statistical analyses included diversity metrics, correlation analysis and predictive modelling using LASSO regression and receiver operating characteristic curves.Results. Microbial richness was significantly higher in BV, Re-BV and IBV groups compared to controls. Lactobacillus abundance decreased progressively from IBV to BV, while Gardnerella, Prevotella, Sneathia, Fannyhessea and Dialister increased. These genera were positively correlated with vaginal pH, human papillomavirus (HPV) status and enzymatic activity. IL-6, IL-10 and IL-1β levels were elevated in BV, IBV and Re-BV groups. IL-10 and IL-1β were further increased in recurrent cases. A combined predictive model integrating microbial and cytokine markers achieved an area under the curve of 0.928 for BV recurrence.Conclusion. Distinct shifts in vaginal microbiota composition and inflammatory factor levels occur during BV formation and recurrence. The integration of microbial and cytokine profiles offers a robust approach for predicting BV recurrence, with important implications for clinical management and prevention strategies.