Role of Enterococcus faecalis surface protein Esp in the pathogenesis of ascending urinary tract infection

Enterococcus faecalis bacteria isolated from patients with bacteremia, endo carditis, and urinary tract infections more frequently express the surface protein Esp than do fecal isolates. To assess the role of Esp in colonizati on and persistence of E. faecalis in an animal model of ascending urinary t ract infection, we compared an Esp(+) strain of E. faecalis to its isogenic Esp-deficient mutant. Groups of CBA/J mice were challenged transurethrally with 10(8) CFU of either the parent or mutant strain, and bacteria in the urine, bladder, and kidneys were enumerated 5 days postinfection, Significa ntly higher numbers of bacteria were recovered from the bladder and urine o f mice challenged with the parent strain than from the bladder and urine of mice challenged with the mutant. Colonization of the kidney, however, was not significantly different between the parent and mutant strains, Histopat hological evaluations of kidney and bladder tissue done at 5 days postinfec tion did not show marked histopathological changes consistent with inflamma tion, mucosal hyperplasia, or apoptosis, and there was no observable differ ence between the mice challenged with the parent and those challenged with the mutant. We conclude that, while Esp does not influence histopathologica l changes associated with acute urinary tract infections, it contributes to colonization and persistence of E, faecalis at this site.