In Vitro Antimicrobial Activity of Razupenem (SMP-601, PTZ601) against Anaerobic Bacteria

We evaluated the in vitro antianaerobic activity of razupenem (SMP-601, PTZ601), a new parenterally administered carbapenem, against 70 reference strains and 323 clinical isolates. Razupenem exhibited broad-spectrum activity against anaerobes, inhibiting most of the reference strains when used at a concentration of <= 1 mu g/ml. Furthermore, it exhibited strong activity, comparable to those of other carbapenems (meropenem and doripenem), against clinically isolated non-fragilis Bacteroides spp. (MIC(90)s of 2 mu g/ml), with MIC(90) values of 0.06, 0.03, and 0.5 mu g/ml against Prevotella spp., Porphyromonas spp., and Fusobacterium spp., respectively. Clinical isolates of anaerobic Gram-positive cocci, Eggerthella spp., and Clostridium spp. were highly susceptible to razupenem (MIC(90)s, 0.03 to 1 mu g/ml).