IN VITRO COMBINATION EFFECTS OF ASTROMICIN AND BETA-LACTAM ANTIBIOTICS AGAINST CFS-SENSITIVE AND CFS-RESISTANT PSEUDOMONAS AERUGINOSA

IN VITRO SYNERGISTIC ACTIVITY

Abstract

We investigated in vitro synergistic activity of astromicin (ASTM) combined with β-lactam antibiotics cefsulodin (CFS), cefoperazone (CPZ), ceftazidime (CAZ), piperacillin (PIPC) and fosfomycin (FOM) against fresh clinical isolated Pseudomonas aeruginosa, which consisted of 13 CFS sensitive (MIC≤3.13μg/ml) and 19 CFS resistant (MIC≥400μg/ml) strains according to the FIC index. Against CFS-sensitive P. aeruginosa, ASTM showed good synergistic activities when combined with PIPC (54%), CAZ (38%), CPZ (23%) and CFS (8%). Against CFS-resistant P. aeruginosa, ASTM also showed high synergistic activities when combined with CAZ (63%), CPZ (47%), PIPC (37%) and CFS (11%). Among the CFS-resistant P. aeruginosa, one clinical isolate showed a high sensitivity (MIC0.78μg/ml) against ASTM alone.