The in vitro antibactericidal activity of cefepime (CFPM) was compared with that of cefpirome (CPR) and ceftazidime (CAZ) against imipenem/cilastatin (IPM/CS)-resistant Pseudomonas aeruginosa. The MIC90 of CFPM, CPR, CAZ and IPM/CS was 32, 128, 64 and 64 μg/ml respectively against 50 clinical isolates of P. aeruginosa. Fourteen of the 50 strains were IPM/CS-resistant. The MIC90 of CFPM, CPR and CAZ was 16, 32 and 32 μg/ml respectively against IPM/CS-resistant P. aeruginosa. The IPM/CS-resistant strains showed no cross-resistance between IPM/CS and CFPM. We observed a lack of the outer membrane protein D2 in the IPM/CS resistant strains using SDS-PAGE. The time courses of CFPM, CPR and CAZ bactericidal activities against 2 strains of IPM/CS-resistant strains were determined. The bactericidal activity of CFPM was equal to or somewhat superior to those of CPR and CAZ at concentration of MIC or subMIC. On the other hand, inducer activities of CFPM and CAZ for β-lactamase were lower than that of CPR. In an inhibition study, CFPM showed a much higher Ki value for cephalosporinase of P. aeruginosa PRC 316 than did CPR and CAZ. An extremely lower affinity of CFPM was demonstrated.
ASJC Scopus subject areas
- Pharmacology (medical)