Beta-Lactamase Stability of HR 756, a Novel Cephalosporin, Compared to That of Cefuroxime and Cefoxitin

Abstract

The stability to β-lactamase hydrolysis of HR 756, a new cephalosporin antibiotic, was compared to the β-lactamase stability of cefoxitin and cefuroxime. HR 756, cefoxitin, and cefuroxime were not hydrolyzed by Richmond type I, III, IV, and V β-lactamases. Antibacterial activity of HR 756 correlated well with resistance to β-lactamase hydrolysis except against Pseudomonas aeruginosa . HR 756, cefoxitin, and cefuroxime inhibited type I β-lactamases, but not type III, IV, or V enzymes. HR 756 was the most active inhibitor.