In vitro inhibitory and bactericidal activity of cefpiramide and seven antipseudomonal agents against Pseudomonas aeruginosa.

Cefpiramide was tested against 493 clinical isolates of Pseudomonas aeruginosa and the results of minimal inhibitory concentration, minimal bactericidal concentration, bactericidal rate, and time-kill synergy studies were compared with those obtained with seven other antipseudomonal agents. The minimal inhibitory concentrations of cefpiramide for P. aeruginosa were comparable to all of the agents tested. Minimal bactericidal concentration results were generally within one twofold dilution of the minimal inhibitory concentration values for all agents tested. Bactericidal rate studies showed that at concentrations of four times the minimal inhibitory concentration, all of the agents produced rapid killing. Results of time-kill synergy studies showed a marked synergistic interaction between cefpiramide and each of three aminoglycosides, gentamicin, tobramycin, and amikacin. These results suggest that cefpiramide may be useful in the therapy of infections due to P. aeruginosa.