In vitro susceptibility testing of ceftobiprole against 880 European respiratory tract infection isolates of methicillin-resistant Staphylococcus aureus followed by whole genome sequencing of ceftobiprole-resistant isolates.

Ceftobiprole was active (MIC, ≤2 mg/L) against most isolates (99.7%; 877/880) of methicillin-resistant Staphylococcus aureus from respiratory tract infections collected in 14 European countries during 2016-2017. Whole-genome sequence analysis showed that two of the three ceftobiprole-resistant (MIC, 4 mg/L) isolates identified were clonal complex 8 (CC8) and one was CC5, and that different mutations were present in genes encoding penicillin-binding proteins, mecA, and other proteins in each ceftobiprole-resistant isolate.