Expression of Mex AB-Opr M efflux pump system and meropenem resistance in Pseudomonas aeruginosa isolated from surgical intensive care unit

Background: Meropenem resistance of Pseudomonas aeruginosa (P. aeruginosa) is considered an increasing problem. Efflux pump one multiple mechanisms that are responsible for this resistance. This study aimed to phenotypically and genotypically detect prevalence efflux mediated meropenem among P. isolates. Methods: Pseudomonas was isolated from different clinical specimens identified by conventional methods confirmed Vietek MS Malditof Mass Spectroscopy. Antibiotic susceptibility test done disc diffusion method then minimum inhibitory concentrations (MIC) detected twice agar dilution without after addition  carbonyl cyanide m-chlorophenylhydrazone (CCCP). genes were polymerase chain reaction ( PCR). Results: Out 265 specimens, 78 with isolation rate (29.4%). By MIC methods, 35 (44.8%) isolates resistant. There a significant difference regarding distribution in resistant as 23 (65.7%) positive 12 (34.3%) negative (p value= 0.13). The MICs significantly decreased CCCP where 21 (60%) had pump-overexpressing phenotype value =0.001). Conclusion: High including, mex A, B opr M.