In-vitro activity of a new penem FCE 22101.

The in-vitro activity of a new penem FCE 22101 was evaluated in comparison with other antimicrobial agents against 966 aerobic and anaerobic Gram-negative and Gram-positive bacteria. FCE 22101 inhibited 90% of Enterobacteriaceae, Haemophilus influenzae, H. parainfluenzae, H. ducreyi, Neisseria gonorrhoeae, Branhamella catarrhalis, Staphylococcus aureus, Staph. epidermidis and group B streptococcus at concentrations of 0.12-4.0 mg/l. Pseudomonas aeruginosa was resistant with MIC90 of greater than 32 mg/l. Streptococcus faecalis displayed MIC90 of 16 mg/l. Bacteroides fragilis, Clostridium spp., Peptococcus spp. and Peptostreptococcus spp. were inhibited at concentrations of 0.25-2.0 mg/l. beta-Lactamase-producing or methicillin resistant bacteria did not have significantly elevated MICs. FCE 22101 was generally less active than imipenem but more active than other beta-lactam antibiotics examined.