Molecular Characterization of Some Carbapenem-resistance Genes among Pseudomonas Aeruginosa Isolated from Wound And Burn Infections in Duhok City, Iraq

Abstract

Background Pseudomonas aeruginosa is an opportunistic pathogen causes severe nosocomial infections among burn and wound patients. Multi-drug resistant strains namely carbapenems antibiotics have mentioned worldwide. Objectives The aim of this study was to know the incidence, patterns of antibiotic susceptibility and molecular characterization of P . aeruginosa isolates among wound and burn hospitalized patients. Methods From September 2019 till September 2020, a total of 524 burn and wound swabs were collected from inpatients at Burn and Emergency Hospital, Duhok city, the Kurdistan region, Iraq. The swabs were cultured and bacterial isolates were identified manually through microbiological tests then by Vitek2 compound system. The isolates were checked for their antibiotic susceptibility patterns then subjected to Polymerase Chain Reaction ( PCR) assay using a set of specific primers for detection of (OprD, blaVIM, blaIMP) carbapenem-resistance genes. Result About 60 (11.4%) isolates were identified as P . aeruginosa; 33 (55%) from female and 27 (45%) from male. Wound isolates exhibited pretty higher resistance over burn against 24 tested antibiotics. Imipenem; meropenem resistance rates were as (33.3 %; 31.7%) and (32.6%; 26.1%) for burn and wound, respectively. High resistance to piperacillin & ticarcillin (75% for both), ticarcillin/clavulanic acid (66.7 %) and tobramycin (63.6 %) were noticed in burn isolates. Colistin and piperacillin/tazobactam exhibited very low resistance. PCR assay indicated that 48 (96%) isolates were contained either single or double genes. OprD was predominated 40 (80 %) isolates then bla VIM gene 8 (16 %) isolates, while no bla IMP gene was detected. About 8 isolates were harbored double resistance genes (OprD, bla VIM) simultaneously and unexpectedly 1 (12%) of these isolate was phenotypic carbapenem-susceptible. moreover, 5 phenotypic carbapenem-resistance isolates were not contained any target resistance genes by PCR assay. Conclusion           Occurrence of P . aeruginosa as a harbor of multiple carbapenemase resistance genes is increasing over time limiting the treatment options to this serious infection. The data support basic mechanism of imipenem resistance could be mostly via the loss of OprD. Colistin and piperacillin/tazobactam have high efficacy