Mezlocillin: In Vitro Studies of a New Broad-Spectrum Penicillin

Abstract

Mezlocillin is a new semisynthetic penicillin that inhibited 71% of the isolates of Serratia marcescens , 67% of Escherichia coli , 50% of Enterobacter spp., and 49% of Klebsiella spp. at a concentration of 12.5 μg/ml. It is also active against both indole-positive and -negative Proteus spp. and gram-positive cocci, except penicillin G-resistant Staphylococcus aureus . At a concentration of 100 μg/ml, it inhibited 94% of the isolates of Pseudomonas aeruginosa . It is more active than ampicillin, carbenicillin, and cephalothin against some gram-negative bacilli.