title: Ceftobiprole- and ceftaroline-resistant methicillin-resistant Staphylococcus aureus.
abstract: The role of mecA mutations in conferring resistance to ceftobiprole and ceftaroline, cephalosporins with anti-methicillin-resistant Staphylococcus aureus (MRSA) activity, was determined with MRSA strains COL and SF8300. The SF8300 ceftaroline-passaged mutant carried a single mecA mutation, 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 in pbp2, pbp4, and gdpP but not mecA.
authors.affiliation: Division of Infectious Disease, Department of Medicine, San Francisco General Hospital, San Francisco, California, USA Division of Molecular Medicine, Harbor-UCLA Medical Center, Torrance, California, USA lchan@labiomed.org.
authors.forename: Liana C
authors.initials: LC
authors.lastname: Chan
authors.affiliation: Division of Infectious Disease, Department of Medicine, San Francisco General Hospital, San Francisco, California, USA.
authors.forename: Li
authors.initials: L
authors.lastname: Basuino
authors.affiliation: Division of Infectious Disease, Department of Medicine, San Francisco General Hospital, San Francisco, California, USA.
authors.forename: Binh
authors.initials: B
authors.lastname: Diep
authors.affiliation: Division of Infectious Disease, Department of Medicine, San Francisco General Hospital, San Francisco, California, USA.
authors.forename: Stephanie
authors.initials: S
authors.lastname: Hamilton
authors.affiliation: Division of Infectious Disease, Department of Medicine, San Francisco General Hospital, San Francisco, California, USA.
authors.forename: Som S
authors.initials: SS
authors.lastname: Chatterjee
authors.affiliation: Division of Infectious Disease, Department of Medicine, San Francisco General Hospital, San Francisco, California, USA.
authors.forename: Henry F
authors.initials: HF
authors.lastname: Chambers
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D002511:Cephalosporins / Q000494:pharmacology*; D024901:Drug Resistance, Multiple, Bacterial / Q000235:genetics; D055624:Methicillin-Resistant Staphylococcus aureus / Q000187:drug effects*; D008826:Microbial Sensitivity Tests; D000097583:Ceftaroline
chemical_list: D000900:Anti-Bacterial Agents; D002511:Cephalosporins; D000097583:Ceftaroline; C443755:ceftobiprole