Ceftobiprole- and Ceftaroline-Resistant Methicillin-Resistant Staphylococcus aureus

Abstract

ABSTRACTThe role ofmecAmutations in conferring resistance to ceftobiprole and ceftaroline, cephalosporins with anti-methicillin-resistantStaphylococcus aureus(MRSA) activity, was determined with MRSA strains COL and SF8300. The SF8300 ceftaroline-passaged mutant carried a singlemecAmutation, E447K (E-to-K change at position 447), and expressed low-level resistance. This mutation in COL conferred high-level resistance to ceftobiprole but only low-level resistance to ceftaroline. The COL ceftaroline-passaged mutant, which expressed high-level resistance to ceftobiprole and ceftaroline, had mutations inpbp2,pbp4, andgdpPbut notmecA.