Substances Secreted by spp. from the Urinary Tract Microbiota Play a Protective Role against Infections and Their Complications.

urinary tract infections can lead to serious complications such as development of urinary stones. spp., belonging to the natural microbiota of the urinary tract, exhibit a number of antagonistic mechanisms against uropathogens, including the secretion of organic acids. In this study, we determined the anti-adhesion, anti-cytotoxicity and anti-crystallization properties of the substances secreted by . For this purpose, membrane inserts with a pore diameter 0.4 μm were used, which prevent mixing of cultured cells, simultaneously enabling the diffusion of metabolic products. The intensity of crystallization was assessed by measuring the levels of Ca, Mg and NH and by observing crystals using microscopic methods. The cytotoxicity of the HCV-29 cell line was determined using the LDH and MTT assays, and the impact of lactobacilli on adhesion to the bladder epithelium was assessed by establishing CFU/mL after cell lysis. It was shown that in the presence of the adhesion of and the cytotoxicity of the cells decreased. The degree of crystallization was also inhibited in all experimental models. Moreover, it was demonstrated that is characterized by the secretion of a high concentration of L-lactic acid. These results indicate that L-lactic acid secreted by has a significant impact on the crystallization process and pathogenicity of .