细菌性阴道病（BV）持续感染严重影响女性生殖健康，且具有高复发率。目前认为阴道加德纳菌生物膜的形成是BV复发的重要原因，而乳杆菌可抑制其生物膜的形成，但分子机制尚未阐明。本课题组前期分离了显著抑制阴道加德纳菌生物膜形成的卷曲乳杆菌262-1，并建立了基于高通量测序的BV复发队列。基于此本研究将扩展该队列，阐明BV复发阴道加德纳菌生物膜形成与变化规律，解析生物膜基质—胞外聚合物（EPS）的构成；明确卷曲乳杆菌262-1影响阴道加德纳菌生物膜形成的抑制因子及其作用于EPS的具体靶点；构建阴道加德纳菌EPS靶点突变体并解析抑制因子作用于EPS靶点的效应因子和代谢通路，阐明“抑制因子—效应因子—EPS靶点”互作的分子机制，揭示卷曲乳杆菌262-1抑制BV复发阴道加德纳菌生物膜形成机制。研究结果将为阴道加德纳菌生物膜靶向抗菌制剂的开发提供新靶点，为治疗BV和降低BV复发提供理论依据和新途径。

Bacterial vaginosis (BV) is a prevalent multifactorial disease of women, caused by an imbalance of the vaginal microbiome and impact the health of genital tracts. The high rate of BV recurrence may be explained by the presence of Gardnerella vaginalis dominated biofilms, which protects the bacteria from antibiotic treatment and serves as a reservoir for pathogens regrowth. Lactobacillus was proved to effectively disrupt the G. vaginalis biofilm and inhibit the biofilm formation. However, its molecular mechanism is still unknown. In our previous study, we isolated the Lactobacillus crispatus 262-1 strain that could efficiently inhibit the growth of G.vaginalis in vitro, and constructed a clinical BV-high-recurrence cohort. Therefore, based on our previous work, this project will extend the BV-high-recurrence cohort and establish the G. vaginalis strain library. The law of the G. vaginalis biofilm formation and change during BV recurrence will be illuminated. And the composition of the biofilm matrix extracellular polymeric substance (EPS) will be analyzed to confirm the key EPS component that affects BV recurrence. Moreover, the inhibiting factor that affects the G. vaginalis biofilm formation will be identified from different components of the extracellular metabolites of L. crispatus 262-1 and its effect target towards EPS will be confirmed. Furthermore, the EPS target mutant G. vaginalis strain will be constructed for comparative transcriptome analysis with the wild type strain. The difference in a whole-genome transcriptome between two strains in presence of the inhibiting factor will be profiled to screen the effector involved in the interaction between the inhibiting factor and the EPS target. To verify the functional role of the effector, the biofilm formation in the effector mutant G. vaginalis strain will be investigated in presence of the inhibiting factor, revealing the molecular mechanism of inhibition of G. vaginalis biofilm formation by L. crispatus 262-1. Our results will provide novel targets for antimicrobial agent development to inhibit the G. vaginalis biofilm formation and further knowledge about clinical treatment to BV-high-recurrence patients.