Evaluation of inhibitory activity of domestic probiotics for against invasion and infection by Proteus mirabilis in the urinary tract

Approximately 5% of men and 40%-50% of women have experienced urinary tract infections (UTI), which are the most common infectious diseases and nosocomial infections in humans. Proteus mirabilis is susceptible to most antibiotics, but antibiotic treatment usually causes side effects. In this research, lactic acid bacteria (LAB) was assessed for its inhibitory activity against a urinary tract pathogen. We studied the effect of pH adjustment, heat, and enzyme treatments on the inhibitory activity of LAB strains and their supernatants, using well-diffusion and co-culture assays. In the cell culture assay, anti-adhesion and anti-invasion activities against P. mirabilis were tested with SV-HUC-1 urothelial cells. LAB were able to adhere to the urothelial cells and inhibited P. mirabilis growth. LAB were also able to inhibit P. mirabilis adhesion to or invasion of SV-HUC-1 urothelial cells. Finally, in the competition assay, LAB showed inhibitory effects against P. mirabilis. LAB could also inhibit the invasion of P. mirabilis into urothelial cells. Two LAB strains (PM206 and 229) exhibited antagonistic activity against P. mirabilis adhesion or invasion of urothelial cells in culture. In the future, probiotics may be used in food or urinary tract cleansing and could replace antibiotic treatments.