Inhibition of Neisseria gonorrhoeae Epithelial Cell Interactions by Vaginal Lactobacillus Species

High levels of Lactobacillus , the dominant genus of the healthy human vaginal microbiota, have been epidemiologically linked to a reduced risk of infection following exposure to the sexually transmitted pathogen Neisseria gonorrhoeae . In this work, a cell culture model of gonococcal infection was adapted to examine the effects of lactobacilli on gonococcal interactions with endometrial epithelial cells in vitro. Precolonization of epithelial cells with Lactobacillus jensenii , Lactobacillus gasseri ATCC 33323, or L. gasseri ATCC 9857 reduced gonococcal adherence by nearly 50%. Lactobacilli also inhibited gonococcal invasion of epithelial cells by more than 60%, which was independent of the effect on adherence. Furthermore, lactobacilli were able to displace adherent gonococci from epithelial cells, suggesting that these organisms have potential as a postexposure prophylactic. Thus, vaginal lactobacilli have the ability to inhibit gonococci at two key steps of an infection, which might have a significant effect in determining whether the gonococcus will be able to successfully establish an infection following exposure in vivo.