Vaginal <i>Lactobacillus</i> postbiotics ameliorate <i>Gardnerella vaginalis</i> -induced bacterial vaginosis by regulating vaginal microbiota and restoring Th17/Treg balance

AIMS: Vaginal health is crucial to a woman's overall well-being. Bacterial vaginosis, a common gynecological condition resulting from dysbiosis, remains a significant clinical challenge. This study aims to investigate whether postbiotics derived from vaginal Lactobacillus strains exhibit therapeutic effects against bacterial vaginitis. METHODS AND RESULTS: Postbiotics, consisting of inanimate microorganisms and/or their components, were analyzed and found to contain lactic acid and acetic acid as the primary acidic constituents. In a model of Gardnerella vaginalis-induced bacterial vaginosis, postbiotics demonstrated enhanced antibacterial and antioxidant activities. They significantly alleviated clinical symptoms, modulated the composition of the vaginal microbiota, and increased microbial diversity. Specifically, postbiotics reduced the abundance of endotoxin-producing Escherichia-Shigella and Enterobacteriaceae, while promoting beneficial bacteria such as Muribaculaceae, Lachnospiraceae, and Streptococcus. Additionally, postbiotic treatment restored the balance between Th17 and Treg cells and regulated associated inflammatory factors. CONCLUSIONS: These findings indicate that postbiotics improve bacterial vaginitis through multiple mechanisms, including antibacterial and antioxidant effects, immune regulation, and restoration of vaginal flora structure and metabolic balance. This study highlights the potential clinical value of postbiotics in the treatment of bacterial vaginosis.