The in-vitro activity of a novel penem FCE 22101 compared to other beta-lactam antibiotics.

FCE 22101 is a penem antibiotic which inhibits the majority of Enterobacteriaceae, Haemophilus influenzae, and Neisseria gonorrhoeae at concentrations of 0.5-4 mg/l. It inhibits staphylococci, haemolytic streptococci and Streptococcus pneumoniae at less than or equal to 0.25 mg/l. Pseudomonas aeruginosa and other Pseudomonas species are resistant. Bacteroides fragilis and Clostridium species are inhibited by less than or equal to 1 mg/l. FCE 22101 is not hydrolyzed by the common plasmid and chrosmosomal beta-lactamases. It shows minimal discrepancy between MIC and MBC values and there is minimal effect of inoculum size. Although FCE 22101 is generally less active against Enterobacteriaceae than are cefotaxime and ceftazidime, it does inhibit some Enterobacter spp. resistant to these agents. FCE 22101 and imipenem are similar in activity against Gram-positive and anaerobic species.