Antibiotic Resistance and Substrate Profiles of the Class A Carbapenemase KPC-6

Abstract

ABSTRACT The class A carbapenemase KPC-6 produces resistance to a broad range of β-lactam antibiotics. This enzyme hydrolyzes penicillins, the monobactam aztreonam, and carbapenems with similar catalytic efficiencies, ranging from 10 5 to 10 6 M −1 s −1 . The catalytic efficiencies of KPC-6 against cephems vary to a greater extent, ranging from 10 3 M −1 s −1 for the cephamycin cefoxitin and the extended-spectrum cephalosporin ceftazidime to 10 5 to 10 6 M −1 s −1 for the narrow-spectrum and some of the extended-spectrum cephalosporins.