Survey of antibiotic resistance in Pseudomonas aeruginosa by The Tokyo Johoku Association of Pseudomonas Studies

Pseudomonas aeruginosa resistance (minimum inhibitory concentration [MIC], ≥16 μg/ml defined as resistant) to meropenem, imipenem, panipenem, piperacillin, ceftazidime, cefozopran, cefoperazone, sulbactam/cefoperazone, amikacin, and tobramycin, as well as cross-resistance profiles, were investigated in P. aeruginosa strains isolated at eight hospitals in the Johoku area, Tokyo, during November 1998. Overall, 8.3% of isolates were imipenem-resistant and 4.6% were ceftazidime-resistant. However, the incidence of antibiotic-resistant P. aeruginosa was distinctly different at each hospital. P. aeruginosa resistance to imipenem ranged from (MIC) 1 to 64 μg/ml (MIC₉₀ 32 μg/ml), and its resistance to ceftazidime ranged from 2 to more than 128 μg/ml (MIC₉₀, 64 μg/ml). Meropenem (MIC range, ≤0.25 to 16 μg/ml) was more active than panipenem (MIC range, 2 to 64 μg/ml). Cefozopran was more active than piperacillin, cefoperazone, or sulbactam/cefoperazone, but many strains were resistant to cefoperazone (17/57). Our analysis found cross-resistance to many beta-lactams, but the degree of cross-resistance was very variable. Received: October 27, 2000 / Accepted: April 10, 2001