IDENTIFICATION OF NOVEL STAPHYLOCOCCAL VIRULENCE GENES BY IN-VIVO EXPRESSION TECHNOLOGY

We have applied in vivo expression technology (IVET) to the study of s taphylococcal virulence. Using a promoter trap that relies on genetic recombination as a reporter of gene expression, we identified 45 staph ylococcal genes that are induced during infection in a murine renal ab scess model. Of these, only six were known previously; 11 others have homology to known non-staphylococcal genes. The known staphylococcal g enes include agrA, part of a key locus regulating numerous virulence p roducts, and a glycerol ester hydrolase, which may enhance staphylococ cal survival in abscesses. We constructed 11 strains containing mutati ons in previously unknown ivi genes. Of these strains, seven were sign ificantly attenuated in virulence compared with the wild-type parent. The mutagenized ivi genes may encode novel staphylococcal virulence fa ctors.