Comparative in vitro activity of the new oral penem ALP-201 against aerobic and anaerobic bacteria.

The in vitro activity of the new penem derivative ALP-201 against 226 aerobic and 350 anaerobic clinical bacterial isolates was determined using agar dilution techniques. For comparison amoxicillin, cefaclor, ceftazidime, doxycycline, erythromycin, imipenem and trimethoprim/sulfamethoxazole were also tested with aerobic bacteria, and cefoxitin, chloramphenicol, clindamycin, imipenem, metronidazole and piperacillin with anaerobic bacteria. ALP-201 was found to be highly active against Escherichia coli, Klebsiella spp., Enterobacter spp., Haemophilus influenzae, Branhamella catarrhalis, Staphylococcus aureus, Streptococcus pneumoniae, Streptococcus pyogenes, anaerobic cocci, Propioni-bacterium acnes, Clostridium perfringens, Bacteroides fragilis, Bacteroides spp. and fusobacteria. Pseudomonas aeruginosa and Clostridium difficile were resistant to ALP-201. When tested against aerobic bacteria using a high inoculum or using the broth dilution technique, the activity of ALP-201 showed little dependence on inoculum size and the bactericidal activity was similar to the inhibitory activity. Further investigations are warranted with ALP-201, which is absorbed from the gastrointestinal tract after oral administration.