Study on the drug resistance and β-lactamases of Pseudomonas aeruginosa

Objective To analyze the resistance and β-lactamases of 93 strains of Pseudomonas aeruginosa. Methods Antimicrobial activity to 93 strains of Pseudomonas aeruginosa were determined by K-B test,and the β-lactamases produced by these strains were characterized by isoelectric focusing,three-dimensional test,2-mercaptopropanoic acid inhibited assays,and polymerase chain reaction (PCR). Results The resistance of amikacin ,cefepime ,cefoperazone/sulbactam,ceftazidime,meropenem were 82.8%,81.7%, 81.7%, 80.6%,77.4%,respectively. The susceptibility of rate imipenem was 71.0%. Three-dimensional test showed that 14 strains produced carbapenemases,only and 2 strain produced metallo-β-lactamase,which was in agreement with the result of 2-mercaptopropanoic acid inhibited assays,13 strains produced AmpC enzymes,and 2 strains produced AmpC enzymes and ESBLs.The 15 strains and other two(Number 19,54) had 1 band on IEF electrophoresis, and the isoelectric points were 9.0 and 6.3 respectively.The 2 metallo-β-lactamases were revealed by amplified PCR products with VIM-2 specific PCR,the production was sequenced and revealed that the found to match with the known sequences of VIM-2. Conclusion The production of carbapenemases and AmpC enzymes was the main cause for multi-drug resistance in Pseudomonas aeruginosa in our hospital.