Urinary tract infection (UTI) is one of the most common bacterial infections in the world, and uropathogenic Escherichia Coli (UPEC) is the principal pathogen of UTI. Escherichia coli (E. coli) outer membrane protease T (OmpT), a member of the omptin family with high substrate specificity, is supposed to be involved in the pathogenesis of E.coli. Methods: In order to explore the role of OmpT in UPEC-induced UTI, an ompT gene deletion mutant of UPEC strain CFT073 was constructed by using the RED

more »

... recombineering, then its biological properties were analyzed with in vitro model of human unthelial cell strain 5637 and in vivo model of C57B/L6 mouse. Results: The in vitro adhesion showed that the adhesion rate for the mutant (COTD) was about 60% of the parent strain CFT073 (P < 0.05). For the in vitro invasion assay, the invasion rate of the CFT073 was as 2.5 times as that of the mutant (P < 0.01). For the in vivo invasion assay, the E. coli strains wild-type and mutant (COTD) was inoculated into the bladder of the C57B/L6 mice, respectively. After 12 h of inoculation, the bladder tissues were collected and used for colony counting. The results showed that the colonization number of the mutant (COTD) was significantly fewer than that of the CFT073. The colonization number of the mutants was about 4.0 × 106 cfu, which was also obviously fewer than that of the CFT073 (1.9 × 107 cfu) (P < 0.01). By using the method of ␤-galactosidase in situ staining, we found that the mutant was defective in the ability of intracellular bacterial community (IBC) formation, which is an important indicator of pathogenicity for UPEC. Conclusion: Taken together, this study has suggested that ompT plays an important role of the pathogenesis of uropathogenic Escherichia Coli, however, the detailed regulatory mechanisms between the genes still need further study. http://dx.