In vitro postantibiotic effects of tomopenem (CS-023) against Staphylococcus aureus and Pseudomonas aeruginosa.

The postantibiotic effect (PAE) of tomopenem was determined after a 2 h exposure of two strains of meticillin-susceptible and meticillin-resistant Staphylococcus aureus (MSSA and MRSA), and imipenem-susceptible and imipenem-resistant Pseudomonas aeruginosa, to tenfold the respective MIC. The PAEs on MSSA and P. aeruginosa were approximately 1 h and they were comparable to those of meropenem. The PAE on MRSA was 1.5 to 3 h, equal to or longer than those of vancomycin. The PAEs of tomopenem not only were found for MRSA, but also were present in the imipenem-resistant P. aeruginosa tested.