Presence of a Polymicrobial Endometrial Biofilm in Patients with Bacterial Vaginosis

OBJECTIVE To assess whether the bacterial vaginosis biofilm extends into the upper female genital tract. STUDY DESIGN Endometrial samples obtained during curettage and fallopian tube samples obtained during salpingectomy were collected. Endometrial and fallopian tube samples were analyzed for the presence of bacteria with fluorescence-in-situ-hybridisation (FISH) analysis with probes targeting bacterial vaginosis-associated and other bacteria. RESULTS A structured polymicrobial Gardnerella vaginalis biofilm could be detected in part of the endometrial and fallopian tube specimens. Women with bacterial vaginosis had a 50.0% (95% CI 24.0-76.0) risk of presenting with an endometrial Gardnerella vaginalis biofilm. Pregnancy (AOR  = 41.5, 95% CI 5.0-341.9, p<0.001) and the presence of bacterial vaginosis (AOR  = 23.2, 95% CI 2.6-205.9, p<0.001) were highly predictive of the presence of uterine or fallopian bacterial colonisation when compared to non-pregnant women without bacterial vaginosis. CONCLUSION Bacterial vaginosis is frequently associated with the presence of a structured polymicrobial Gardnerella vaginalis biofilm attached to the endometrium. This may have major implications for our understanding of the pathogenesis of adverse pregnancy outcome in association with bacterial vaginosis.