Isolation and Antimicrobial Susceptibility of Imipenem-resistant Pseudomonas aeruginosa

Objective To study the isolation and antimicrobial susceptibility of imipenem-resistant Pseudomonas aeruginosa. Methods Bacteria cultures were identified routinely or by MicroScan WalkAway 96 system. The susceptibilities of the bacteria were detected by disk diffusion method and the results were confirmed with the rules of NCCLS/CLSI. The metallo-β-lactamases were tested with 2-mercaptopropanoic acid inhibited assays. Results The strains of imipenem-resistant Pseudomonas aeruginosa were mostly come from sputum specimens and throat swabs, and the positive rate was 85.0%. The proportion of these strains from ICU was 22.5%, from respiratory department was 18.8%, geriatric medicine 12.5% and neurology department 26.2%. The susceptibility rates of strains to amikacin, ceftazidime, ciprofloxacin, cefoperazone/sulbactam were 48.8%, 32.5%, 27.5%, and 26.3% respectively. The intermediate rate for cefoperazone / sulbactam was 52.5%. The rate of strains producing metallo-β-lactamases was 16.3%. Conclusions The strains of imipenem-resistant Pseudomonas aeruginosa chiefly come from respiratory tract infections, and the susceptibility for almost all the antibiotics is low. To strengthen the monitoring and optimization using of antibiotics is vital to control the prevalence of Pseudomonas aeruginosa.