Tarbiat Modares University Infection Epidemiology and Microbiology 2588-4107 9 1 2023 03 01 Evaluation of the Relative Frequency of Carbapenemase Genes by Phenotypic and Genotypic Methods in Pseudomonas aeruginosa Isolates from Patients with Open Heart Surgery in Iran 55 62 1913 10.52547/iem.9.1.55 EN Maryam Mokhtari Department of Microbiology, School of Medicine, Guilan University of Medical Sciences, Rasht, Iran Ali Mojtahedi Department of Microbiology, School of Medicine, Guilan University of Medical Sciences, Rasht, Iran Nejat Mahdieh Cardiogenetic Research Center, Rajaei Cardiovascular Medical and Research Center, Iran University of Medical Sciences, Tehran, Iran Alireza Jafari Urology Research Center, Razi Hospital, School of Medicine, Guilan University of Medical Sciences, Rasht, Iran Zahra Atrkar Roushan School of Medicine, Guilan University of Medical Sciences, Rasht, Iran Mohammad Javad Arya Anatomical and clinical Pathologist, Fellowship of dermatopathology, Head of Sina Pathobiology Lab, Yazd, Iran. Journal Article <span>Backgrounds:</span> <span>Carbapenem resistance among Pseudomonas aeruginosa strains is alarming. This study aimed to investigate the relative frequency of carbapenem-resistant P. aeruginosa strains by phenotypic and genotypic methods. </span><br> <span>Materials & Methods</span><span>:</span><span> The antibiotic susceptibility pattern of 60 P. aeruginosa isolates was determined by disk diffusion method (Kirby-Bauer).</span> <span>BD Phoenix automated microbiology system was used to identify carbapenem-resistant isolates, and the minimum inhibitory concentration (MIC) was determined </span><span>using E-Test</span><span>. In addition, mCIM (modified carbapenem inactivation method) phenotypic test was performed to evaluate carbapenem resistance genes in P. aeruginosa isolates. The prevalence of metallo-beta-lactamase (MβL) genes in carbapenem-resistant P. aeruginosa isolates was determined using conventional polymerase chain reaction (PCR).</span><br> <span>Findings: </span><span>The frequency of carbapenem-resistant P. aeruginosa isolates was 36% (22 of <span>60)<span>. </span>The highest resistance<span> was observed </span>to </span><span>imipenem and meropenem </span><span>(36.6%),</span> <span>and the highest sensitivity was observed to </span><span>amikacin</span><span> (75%).</span><span> All </span><span>carbapenem-resistant P. aeruginosa</span><span> isolates were confirmed by the BD Phoenix automated system (MIC></span> <span>8 µg/mL for imipenem and meropenem), E-test (</span><span>MIC</span> <span>˂</span><span>32 </span><span>µg/mL</span><span>),</span><span> and </span><span>mCIM assay (the growth inhibition zone diameter was 6-8 mm). </span><span> In </span><span>carbapenem-resistant </span><span>P. aeruginosa</span><span> isolates, the frequency of bla</span>_{<span>VIM</span>}<span>, bla_IMP, and bla_SPM genes was 9.1% (2 of</span><span> 22), </span><span>4.5% </span><span>(1 of 22<span>),</span><span> and 4.5% (1 of 22), respectively</span><span>.</span> <span>Bla_{<span>KPC</span>}</span> <span>and bla_NDMgenes were not found in any of the isolates.</span><br> <span>Conclusion:</span><span> Based on the present study results, all phenotypic tests used to identify carbapenemase-producing isolates had the same sensitivity (100%) and specificity (100%). </span> https://iem.modares.ac.ir/article_1913_c44799b04a1c72e3c8593a53e8000c78.pdf