Abstract:

Objective   To compare drug sensitivity of carbapenems combined with sulbactam or cefoperazone on Pseudomonas Aeruginosa(PA) in vitro. Methods   After the collection of  PA strains, antimicrobial susceptibility test were conducted. The PA strains were divided into sensitive group, multidrug resistant (MDR) group, extensively drug resistant (XDR) group and pan-drug resistant(PDR) group according to the results of antibiotic sensitivity test. The sensitivities of biapenem or imipenem combined with sulbactam, cefoperazone, fosfomycin, amikacin, cefperazone-sulbactam, ciprofloxacin were examined by Kirby-Bauer (K-B) disc agar diffusion method and minimal inhibitory concentration (MIC) assay，then the fractional inhibitory concentration (FIC) indexes were calculated. Results   One hundred and twenty clinical PA strains were collected, including 56 sensitive strains, 36 MDR strains, 13 XDR strains and 15 PDR strains. Biapenem showed synergistic effects with sulbactam, fosfomycin, amikacin and cefoperazone seperately. Synergistic effects were observed in the combinations of imipenem and fosfomycin, sulbactam, amikacin. The antagonistic effects were observed in the combinations of imipenem and  cefopcrazone or cefperazone-sulbactam. Conclusion   Carbapenems combined with fosfomycin，amikacin or sulbactam can be used in the treatment of resistant PA infections, but imipenem combined with cefoperazone is not recommended.

Key words: Carbapenem; Cefoperazone; Pseudomonas Aeruginosa; Multidrug combination