Antibacterial activity of N-formimidoyl thienamycin in comparison with cefotaxime, lamoxactam, cefoperazone, piperacillin gentamicin.

The in vitro activity of N-formimidoyl thienamycin (MK 0787), a new stable derivative of thienamycin was compared with that of lamoxactam, cefotaxime, cefoperazone, piperacillin and gentamicin against 410 clinical isolates of common bacteria. In comparison with the other agents, MK 0787 was more or equally active against Staphylococcus aureus, Streptococcus faecalis, Escherichia coli, Citrobacter spp., Klebsiella spp., and Serratia spp. It inhibited all isolates at a concentration of 0.5 mg/l, but was less active than cefotaxime and lamoxactam against Proteus mirabilis and less active than cefotaxime, lamoxactam and cefoperazone against Beta-lactamase positive Haemophilus influenzae. Strains of Pseudomonas aeruginosa were more susceptible to N-formimidoyl thienamycin than to other antibiotics.