CHLOROCARDICIN, A MONOCYCLIC β-LACTAM FROM A STREPTOMYCES SP.

I. DISCOVERY, PRODUCTION AND BIOLOGICAL ACTIVITIES

Abstract

Chlorocardicin is a new monocyclic β-lactam produced by a Streptomyces sp. It is structurally related to nocardicin A but differs in having a m-chloro substituent on the p-hydroxyphenylglycine unit. The biological activity of chlorocardicin was similar to nocardicin A but the former showed less antagonism in complex media. Moderate in vitro activity was Observed against Enterobacteriaceae and Pseudomonas aeruginosa. Chlorocardicin showed low activity against Staphylococcus aureus whereas nocardicin A was inactive. Both compounds Were shown to be strongly potentiated by antibiotics that inhibit peptidoglycan biosynthesis and Were antagonized by selected L-and D-amino acids.