Lactobacillus crispatus inhibits growth of Gardnerella vaginalis and Neisseria gonorrhoeae on a porcine vaginal mucosa model

Abstract

BackgroundThe vaginal microbiota can impact the susceptibility of women to bacterial vaginosis (BV) and sexually transmitted infections (STIs). BV is characterized by depletion of Lactobacillus spp., an overgrowth of anaerobes (often dominated by Gardnerella vaginalis) and a pH > 4.5. BV is associated with an increased risk of acquiring STIs such as chlamydia and gonorrhea. While these associations have been identified, the molecular mechanism(s) driving the risk of infections are unknown. An ex vivo porcine vaginal mucosal model (PVM) was developed to explore the mechanistic role of Lactobacillus spp. in affecting colonization by G. vaginalis and Neisseria gonorrhoeae.ResultsThe data presented here demonstrate that all organisms tested can colonize and grow on PVM to clinically relevant densities. Additionally, G. vaginalis and N. gonorrhoeae form biofilms on PVM. It was observed that lactic acid, acetic acid, and hydrochloric acid inhibit the growth of G. vaginalis on PVM in a pH-dependent manner. N. gonorrhoeae grows best in the presence of lactic acid at pH 5.5, but did not grow well at this pH in the presence of acetic acid. Finally, a clinical Lactobacillus crispatus isolate (24-9-7) produces lactic acid and inhibits growth of both G. vaginalis and N. gonorrhoeae on PVM.ConclusionsThese data reveal differences in the effects of pH, various acids and L. crispatus on the growth of G. vaginalis and N. gonorrhoeae on a live vaginal mucosal surface. The PVM is a useful model for studying the interactions of commensal vaginal microbes with pathogens and the mechanisms of biofilm formation on the vaginal mucosa.

Interaction of Gardnerella vaginalis and Vaginolysin with the Apical versus Basolateral Face of a Three-Dimensional Model of Vaginal Epithelium

“…While this is higher than the physiological pH (Ͻ4.5) of a healthy vaginal environment, it is also more characteristic of a G. vaginalis-dominated environment. Since pH could potentially alter bacterial growth and VLY activity (6,79,86), future experiments using these tissues to investigate BV pathogenesis should take this into consideration. Finally, G. vaginalis strains can exhibit significant heterogeneity in both the virulence factors that they express and the degree to which they express them (28,33,51).…”

“…T he healthy vaginal microbiome is dominated by Lactobacillus species that produce lactic acid (1)(2)(3)(4), which is inhibitory toward potentially pathogenic organisms (5)(6)(7). During bacterial vaginosis (BV), Lactobacillus dominance is lost, vaginal pH increases, and the community comprising the vaginal microbiome becomes more diverse (8)(9)(10)(11)(12).…”

Effects of combined oral contraceptives, depot medroxyprogesterone acetate and the levonorgestrel-releasing intrauterine system on the vaginal microbiome

“…For example, Lactobacillus crispatus inhibits infection of HeLa cells by Chlamydia trachomatis , and inhibits growth of Neisseria gonorrhoeae in a porcine model of vaginal mucosa [1,2]. In addition, a recent report suggests that L. crispatus alters cervicovaginal mucus in such a way that trapping of HIV particles in enhanced [3].…”

Species diversity of vaginal lactobacilli in norm and in dysbiotic states

“…Это объясняет-ся способностью L. crispatus поддерживать по-стоянство микробиоценоза влагалища за счет выраженных протективных свойств, препят-ствующих размножению условно-патогенных микроорганизмов [19,20].…”