Effects of ceftobiprole and oxacillin on mecA expression in methicillin-resistant Staphylococcus aureus clinical isolates

Abstract

Induction of mecA by ceftobiprole and oxacillin in 18 methicillin-resistant Staphylococcus aureus clinical isolates with various SCCmec cassettes was examined using reverse transcriptase PCR. The magnitude of mecA induction, 3- to 65-fold for ceftobiprole and 2- to 69-fold for oxacillin, did not correlate with ceftobiprole MICs (<or=4 microg/ml), although the 11 isolates with at least 13-fold induction by oxacillin all had oxacillin MICs of >or=256 microg/ml. No correlation between magnitude of induction and SCCmec type was found.