C-19393-S2 AND C-19393-H-2, NEW CARBAPENEM ANTIBIOTICS .4. INHIBITORY ACTIVITY AGAINST BETA-LACTAMASES

New carbapenem antibiotics, C 19393 S2 and H2, are potent and broad spectrum inhibitors of .beta.-lactamases. Among 11 types of .beta.-lactamases tested, those from Escherichia coli (plasmid-bearing), Klebsiella pneumoniae, Proteus vulgaris, Serratia marcescens and Bacteroides fragilis were especially sensitive. They also inhibited cephalosporinases insensitive to clavulanic acid. The inhibition by C-19393 S2 and H2 was of progressive type, except for the inhibition of E. coli enzyme (plasmid-mediated type I) by C-19393 H2. The inhibition of E. coli .beta.-lactamase by C-19393 S2 was irreversible, while that by C-19393 H2 was reversible.