Characterization by phenotypic and genotypic methods of carbapenemase-producing Pseudomonas aeruginosa Strains Isolated from intensive care units

Introduction and Objectives: Carbapenems are one of the first-choice antibiotics for the treatment of Pseudomonas aeruginosa infections.but increase resistance to carbapenems in hospitals especially in intensive care units (ICUs) is a worldwide clinical concern. Resistance is mainly due to carbapenemases enzymes. Therefore, early and correct identify of carbapenemase-producing is important.,The present study was undertaken to detect carbapenemase in strains of P. aeruginosa isolated from ICU patient by using phenotypic and genotypic methods.Material and Methods :A total of 34 clinical specimens were collected from patients from November 2017 to May 2018in Hamedan,Iran.Antibiotic susceptibility tests were conducted by disc diffusion.Determination the minimum inhibitory concentration was done by E-test for imipenem antibiotic.To identify carbapenemases, combined disk tests (CDT) carbapenem inactivation method (CIM) carbaNP, Modified Hodge test (MHT) and genotypic methods were used.Results: During this study, 34 pseudomonas aeroginosa isolates were collected from ICU, between from isolates 15carbapenem-resistant pseudomonas aeroginosa isolates were subjected to CarbaNP ,MCIM,MHT,IMP/EDTA tests, and tested by PCR for blaKPC, blaVIM, blaOXA48, blaSPM, blaSIM, blaGIM, blaAMPC, blaIMP genes .14/15 (93/33%) isolates were positive for carbapenemase production by Carba NP,14/15(93/33%) by MCIM ,9/15 (60%) by using DDST and 6/15 (40%) by MHT tests. Carba NP and MCIM tests showed a high sensitivity, specificity, PPV and NPV compared to PCR in Pseudomonas aeroginosa isolates.Conclusions:Our results showed that carbaNPand carbapenem inactivation method (CIM) tests are highly sensitive ,specific, cheap and rapid tests for the detection of carbapenemase producing in P. aeruginosa isolates.

کلیدواژه ها:

Pseudomonas aeruginosa ، ICU ، phenotypic ، genotypic ، carbapenemase