Decreased virulence of a gls24 mutant of Enterococcus faecalis OG1RF in an experimental endocarditis model

Abstract

In the current study, the gls24 disruption mutant TX10100, previously shown to be more sensitive to bile salts and attenuated in a mouse peritonitis model, showed an approximately fivefold higher 50% infective dose than wild-type OG1RF in a rat endocarditis model. When administered as a mixture, TX10100, unlike a downstream glsB mutant, was significantly outnumbered by OG1RF in vegetations, organs, and blood, despite being inoculated in greater numbers. These results indicate that gls24 is important in the pathogenesis of enterococcal endocarditis.

FIG. 1.

Percentages of OG1RF and the gls24 mutant (TX10100) in the total population of bacteria recovered from tissue samples and blood and in the initial inocula. Three different inocula were used, and bacteria were recovered from animals 72 or 120 h after inoculation. All results from 16 rats were combined, and the mean percentages and standard deviations are shown. Statistical comparison was done using the results for individual rats (see the text) (P < 0.001 by chi-square test).

FIG. 2.

Percentages of OG1RF and the glsB mutant (TX10200) in the total population of bacteria recovered from tissue samples and blood and in the initial inocula. Two different inocula were used and bacteria were recovered from animals 72 h after inoculation. Results from six rats were combined, and the mean percentages and standard deviations are shown.