Staphylococcus aureus Microcapsule Expression Attenuates Bacterial Virulence in a Rat Model of Experimental Endocarditis

Publisher Website
Google Scholar
Abstract
The virulence of the Staphylococcus aureus strains that differed only in capsule expression was compared in a rat model of catheter-induced experimental endocarditis. The ID50 of all the strains was low 3 cfu of S. aureus), suggesting that this model may bemore sensitive than other animal models to differences in bacterial virulence. Compared with the wild-type strains that expressed type 5 or type 8 capsular polysaccharides, mutant strains devoid of capsule had significantly lower ID50 values. In contrast, a mutant that produced scant amounts of the type 5 polysaccharide had an IDso similar to that of the parental type 5 isolate. As the bacterial inoculum was increased, each of the S. aureusstrains reached final concentrations of 1010–1011 cfu/g of vegetation; however, the nonencapsulated mutants colonized the left-sided vegetations at lower inocula than did the wild-type strains. This study indicates that microcapsule expression attenuates bacterial virulence in a rat model of catheter-induced endocarditis.

This publication has 0 references indexed in Scilit: