Importance of the ebp (endocarditis- and biofilm-associated pilus) locus in the pathogenesis of Enterococcus faecalis ascending urinary tract infection - PubMed (original) (raw)

. 2007 Jun 1;195(11):1671-7.

doi: 10.1086/517524. Epub 2007 Apr 26.

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Importance of the ebp (endocarditis- and biofilm-associated pilus) locus in the pathogenesis of Enterococcus faecalis ascending urinary tract infection

Kavindra V Singh et al. J Infect Dis. 2007.

Abstract

Background: We recently demonstrated that the ubiquitous Enterococcus faecalis ebp (endocarditis- and biofilm-associated pilus) operon is important for biofilm formation and experimental endocarditis. Here, we assess its role in murine urinary tract infection (UTI) by use of wild-type E. faecalis OG1RF and its nonpiliated, ebpA allelic replacement mutant (TX5475).

Methods: OG1RF and TX5475 were administered transurethrally either at an ~1 : 1 ratio (competition assay) or individually (monoinfection). Kidney pairs and urinary bladders were cultured 48 h after infection. These strains were also tested in a peritonitis model.

Results: No differences were observed in the peritonitis model. In mixed UTIs, OG1RF significantly outnumbered TX5475 in kidneys (P=.0033) and bladders (P< or =.0001). More OG1RF colony-forming units were also recovered from the kidneys of monoinfected mice at the 4 inocula tested (P=.015 to P=.049), and 50% infective doses of OG1RF for kidneys and bladder (9.1x10(1) and 3.5x10(3) cfu, respectively) were 2-3 log(10) lower than those of TX5475. Increased tropism for the kidney relative to the bladder was observed for both OG1RF and TX5475.

Conclusion: The ebp locus, part of the core genome of E. faecalis, contributes to infection in an ascending UTI model and is the first such enterococcal locus shown to be important in this site.

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Figures

Figure 1

Figure 1

Mixed infection (competition assay) by w.t. E. faecalis OG1RF and nonpiliated TX5475 in the kidneys and urinary bladder of mice (n=16). Data are expressed as log10CFU of w.t. E. faecalis OG1RF or TX5475. The log10CFU/gm from both kidneys were combined and averaged. Solid diamonds and triangles represent w.t. E. faecalis OG1RF and TX5475, respectively, from kidney homogenates and empty diamonds and triangles represent w.t. E. faecalis OG1RF and TX5475, respectively, from urinary bladder homogenates. Horizontal bars represent geometric mean titer. Mean fold difference in CFU are given. Log10 CFU were compared for statistical significance using a paired t test.

Figure 2

Figure 2

Monoinfection (106, 105, 104, and 103 inocula) using w.t. E. faecalis OG1RF or nonpiliated TX5475 in the kidneys of mice (n=10). Data are expressed as log10CFU/gm of w.t. E. faecalis OG1RF or TX5475 recovered from kidney homogenates 48 hrs after transurethral challenge. The log10CFU from both kidneys were combined and averaged. Solid and empty triangles represent w.t. E. faecalis OG1RF and TX5475, respectively. Horizontal bars represent geometric mean titer. Mean difference in CFU is given as log10 ± standard deviation (SD) for the respective inocula. TX5475 CFUs (recovered from kidneys) were significantly reduced versus OG1RF with all four inocula using unpaired t test.

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