Peculiarities of vaginal microbiota in perimenopausal and postmenopausal women with type 2 diabetes mellitus.

BACKGROUND

The changes in the vaginal microbiota and potential dysbiosis adjustment strategies in diabetic patients remain inconclusive. This study was designed to investigate the impact of Type 2 diabetes mellitus (T2DM) on the ecological dynamics of the vaginal microbiota in perimenopausal and postmenopausal women, with a focus on microbial community structure and functional homeostasis.

METHODS

Vaginal secretion samples from 22 T2DM patients (DM group) and 23 healthy controls (CT group) under perimenopausal and postmenopausal conditions were analyzed via metagenomic sequencing. Alpha diversity (Observe, ACE, Shannon-Weaver, Gini-Simpson indices) and beta diversity (PCoA, NMDS) were assessed. Taxonomic profiling, LEfSe analysis, and co-occurrence network construction were performed to identify differential species and microbial interactions. Neutral community modeling evaluated stochastic vs. deterministic assembly processes.

RESULTS

No significant differences were observed in age (62.22 ± 5.74 vs. 58.23 ± 7.55, p = 0.052) or perimenopausal/ postmenopausal status (3/19 vs. 5/18, p = 0.748) between the DM and CT groups. The DM group exhibited significantly higher alpha diversity (p < 0.05) and distinct beta diversity clustering (p < 0.05), marked by reduced Lactobacillus relative abundance (28.7% in CT vs. 6.3% in DM) and increased abundance of opportunistic pathogenic genera (Klebsiella, Gardnerella, Staphylococcus). LEfSe identified Firmicutes as CT biomarkers, while the relative abundance of Bacteroidetes and Prevotella increased in DM group. Both fasting blood glucose and HbA1c levels significantly influenced the relative abundance of vaginal Lactobacillus crispatus, Lactobacillus gasseri, and Lactobacillus iners, showing a significant negative correlation. Co-occurrence networks revealed greater complexity and more integrated in the DM group (more triangles, lower modularity, higher node degrees, higher clustering coefficients, p < 0.0001). Neutral modeling indicated stochastic assembly (R² >0.5), with Lactobacillus species and opportunistic pathogens deviating from neutral predictions in DM.

CONCLUSION

Under perimenopausal and postmenopausal conditions, T2DM disrupts vaginal microbiota homeostasis by diminishing protective Lactobacillus populations and promoting pathogen proliferation.