Effects of ampC gene distribution and AmpC enzyme production in Pseudomonas aeruginosa on drug susceptibility

Objective: To investigate the effects of ampC gene distribution and AmpC enzyme production in Pseudomonas aeruginosa on drug susceptibility.Methods: We detected ampC gene distribution by PCR,cloned and verified the amplified ampC genes by DNA sequencing,measured AmpC β-lactamase production by three-dimensional tests,and determined the susceptibility of Pseudomonas aeruginosato antimicrobial agents by disk diffusion tests.Results: The ampC gene was found to be positive in 97 out of 147 strains by PCR.The PCR product showed complete coincidence with the GenBank ampC sequence.The rate of susceptibility of ampC gene negative strains to imipenam,ceftazidime,cefepime and cefoperazone/sulbactam was ≥ 90.0%,while that of the positive strains to ceftazidime,cefepime and cefoperazone/sulbactam was significantly lower(P 0.05).A total of 88 strains(60.0%) produced AmpC enzyme.The rate of susceptibility of AmpC enzyme negative strains to imipenam,cefoperazone/sulbactam,ceftazidime and cefepime was over 90%,while AmpC enzyme positive strains were only sensitive to imipenam and cefepime.Conclusion: Drug-resistant ampC genes extensively exist in Pseudomonas aeruginosa.The identification of ampC gene distribution and AmpC enzyme production in Pseudomonas aeruginosa is helpful to the selection of antimicrobial agents in the treatment of infection.