The β-lactamase stability of a novel β-lactam antibiotic containing a 7 α-methoxyoxacephem nucleus

Abstract

The susceptibility of a novel 7α-methoxyoxacephem antibiotic—LY127935 (6059S)—has been tested in the presence of a representative range of clinically relevant bacteria. In no case could hydrolysis of the compound be detected at significant rates. The compound proved to be a potent ‘suicide’ inhibitor of the cephalosporinases of Enterobacter cloacae and Pseudomonas aeruginosa, and an effective competitive inhibitor of the cephalosporinase of Bacteroides fragilis. Two β-lactamases (Types IIIa and IVc) which have a broad spectrum of activity against both penicillins and cephalosporins were not inhibited significantly by LY127935.