의생명시스템학부

Numerous urinary tract infections (UTIs) are recurring, owing to the persistence of uropathogens within bladder epithelial cells (BECs) between infections. Due to the intracellular nature of persistent uropathogens, they are frequently resistant to antibiotic therapy. The recent discovery of endogenous Lactobacillus spp. in healthy human bladders prompted the question of whether these endogenous bacteria have an effect on UTIs directly or indirectly. We find that, in comparison to healthy controls, the bladder population of Lactobacilli was significantly reduced in patients with recurrent UTIs. Infected human BECs were exposed in vitro to L. crispatus, which significantly reduced the intracellular uropathogenic Escherichia coli (UPEC) load. Lactobacilli adhering to BECs boosted the production of type I interferon (IFN), hence increasing cathepsin D expression within lysosomes hosting UPECs. In germ-free mice, cathepsin D-mediated lysosomal death was decreased. Intravesicular injection of Lactobacilli to UPEC-infected mouse bladders significantly reduced their load therapeutically. In conclusion, components of endogenous microflora may have anti-UTI activity.