High-Throughput Sequencing-Based Analysis of Changes in the Vaginal Microbiome during the Disease Course of Patients with Bacterial Vaginosis: A Case–Control Study

SIMPLE SUMMARY: Because of their complexity, bacterial communities characteristic of bacterial vaginoses (BV) have not been completely characterized yet. The aim of the present study was to evaluate the changes in different characteristic bacteria during the onset, progression, and remission of BV. We performed a case–control study to investigate the differences in vaginal microbiota during the onset and post-treatment asymptomatic stages of BV. Participants were divided into four groups. We collected vaginal swabs and sequenced the V3–V4 hypervariable regions of bacterial 16S rRNA genes using the Illumina MiSeq platform. The sequencing results were used to evaluate vaginal microbiomes in the four groups. We observed significant differences in the composition and alpha diversity of the vaginal microbiota at different stages of BV, as well as in the distribution of bacterial communities among the investigated groups. We commented on these results and proposed future research directions. We believe that our study makes a significant contribution to the literature because it provides a basis for the screening of possible specific markers of BV, as well as for the prevention, diagnosis, treatment, and efficient monitoring of the disease in clinical practice. ABSTRACT: Background: The vaginal microbiome is closely associated with the onset and recurrence of bacterial vaginosis (BV). In the present study, the state of vaginal microbiota during the onset and post-treatment asymptomatic stages of BV were compared to that of a healthy population to evaluate the changes in different characteristic bacteria during the onset, progression, and remission of BV. Methods: A case–control study was performed to explore these changes. Women with clinical symptoms of BV were divided into the disease group (M) and case–control group (C) based on the Nugent score. Subjects in the disease group whose symptoms were resolved after the treatment were assigned to the treated group (T) and healthy subjects were recruited into the normal control (N) group. The V3–V4 hypervariable regions of bacterial 16S rRNA genes were sequenced on the Illumina MiSeq platform. Results: The N harbored the highest number of detected species and a higher abundance of microbiota; they had a significantly higher abundance of Lactobacillus and different bacterial community composition compared to the other three groups. In group M, Gardnerella vaginalis was the dominant species, whereas Lactobacillus iners was predominant in the other three groups. While Lactobacillus was more commonly present in Group C compared to group M. it was significantly increased in group T. Alpha diversity analysis of bacterial communities revealed significant differences in community richness and diversity among all four groups (p < 0.05). Significant differences in the distribution of various bacterial communities among the different groups were also observed (p < 0.05). Specifically, the abundance of eight bacterial taxa (Megasphaera, Aerococcus christensenii, Clostridiales, Gardnerella, Peptostreptococcus, Veillonellaceae, Akkermansia, Coriobacteriales) differed significantly among the four groups (p < 0.05). Conclusion: Significant differences in the composition and alpha diversity of the vaginal microbiota at different stages of BV and the distribution of bacterial communities were observed among the investigated groups. In addition to Gardnerella, Sneathia sanguinegens and Prevotella timonensis play an important role in the pathogenesis of BV. The appearance of BV-like clinical symptoms was closely associated with the decrease in Prevotella and Atopobium vaginae populations.