Study on the β-lactamases in imipenem-resistant Pseudomonas aeruginosa

Objective To analyze the resistance and β-lactamases of 27 imipenem-resistant Pseudomonas aeruginosa. Methods Antimicrobial activity to 27 imipenem-resistant Pseudomonas aeruginosa were determined by K-B test and the β-lactamases produced by these strains were characterized by three-dimensional test 2-mercaptopropanoic acid inhibited assays and polymerase chain reaction PCR. Results The susceptibility rates to amikacin cefoperazone/sulbactam cefepime were 66.7%?55.6%?51.9%respectively. The resistance rate of meropenem was 29.6% Three-dimensional test indicated 12 strains produced carbapenemases only 2 strain produced metallo-β-lactamase which was in agreement with the result of 2-mercaptopropanoic acid inhibited assays 3 strains produced AmpC enzymes. The 2 metallo-β-lactamase showed the amplified PCR products with VIM-2 specific PCR the production was sequenced and revealed that the nucleotide sequences matched nearly exactly with the known sequences of VIM-2. Conclusion The production of carbapenemases was the main mechanisms for carbapenem resistance in Pseudomonas aeruginosa in our hospital.