Molecular Detection of Plasmid-Mediated Colistin-Resistance Genes in Multi-Drug Resistant Escherichia coli Isolated From Human and Poultry in Duhok City, Iraq

Abstract

HE plasmid-borne colistin resistance gene mcr-types were formerly recognized as plasmid-mediated colistin mechanism among clinical and animal samples Escherichia coli from China and thereafter reported worldwide. The study investigated for screening of plasmid-mediated colistin and carbapenems resistant genes in Escherichia coli isolates from human and poultry origin. After isolation and identification of isolates from clinical specimens and poultry cloacal swab, disc diffusion and broth microdilution method were determined antibiotic susceptibility patterns, phenotypic Extended- Spectrum Beta-lactamase enzymes (ESBL)-production test and phenotypic colistin resistance. Molecular detection by PCR was applied to targeted carbapenems-resistance genes (KPC-2, OXA-48 and NDM-1) and colistin-resistant genes (mcr-1, mcr-2 and mcr-3). The majority of isolates were higher resistance to commonly used antibiotic categories with Multi-Drug Resistance (63 %) and (93 %) of clinical and poultry E coli isolate, respectively. Using broth microdilution (16%) of isolates displayed phenotypic colistin resistance. Human isolates had higher NDM-1 gene (33.3%), while, higher OXA-48 gene (22.2%) was in poultry isolates, and no KPC-2 gene was identified. Only isolates from poultry contained the mcr-1 gene (27.7%), while mcr-2 gene was present only in human isolates (4.7%) and mcr-3 gene in both human (33.3%) and poultry (22.2%) isolates. Negative mcr-1, 2, and 3 isolates expressed high rates of ESBL-production. The coexistence of (mcr-3 + NDM-1) was frequent, including 10 isolates, and one isolate carried (mcr-2+mcr-3+NDM-1) combination from urine samples. Data of colistin resistance among clinical and poultry isolates in this region is scarce. Identification of colistin and carbapenems- resistance genes via plasmids among those isolates menace and approaches pan-resistance and failure treatment.