Exploration of the protein-dependent mechanism of Lactobacillus crispatus GAI98322 to prevent recurrent cystitis

ObjectivesTo elucidate the mechanism of Lactobacillus crispatus (L. crispatus) suppositories to prevent patients from recurrent cystitis (RC), independent from viable-Lactobacilli-bacteria- and acid-dependent ones such as hydrogen peroxide and lactate.MethodsWe used the GAI98322 strain of L. crispatus in all experiments and pH-matched.cell-free culture supernatant of L. crispatus (CFCS) was collected. The growth inhibitory activity and the biofilm formation inhibitory activity of the CFCS against uropathogenic Escherichia coli (UPEC), Extended Spectrum beta (β) Lactamase producing (ESBL+) UPEC, and Pseudomonas aeruginosa (P. aeruginosa) was assessed by agar-disk diffusion tests and crystal violet assay. Also, CFCS was subjected to mass spectrometry to specify ingredients.ResultsThe CFCS suppressed the proliferation of E. coli, ESBL + E. coli, and P. aeruginosa. Also, the CFCS at a concentration of 40% significantly impeded the biofilm formation of these three bacteria. The aggregation-promoting factor and Lysin was detected from CFCS.ConclusionsThe cell-free supernatant from the GAI98322 strain of L. crispatus inhibits the growth/biofilm formation of broad pathogens by aggregation promoting factor and lysin, which may prevent hosts from RC regardless of the antimicrobial resistance of the pathogens and even under pH modulation.