THE FIRST REPORT OF EMERGING MOBILIZED COLISTIN RESISTANCE (MCR) GENES IN E.COLI AND KLEBSIELLA PNEUMONIAE ISOLATES FROM CLINICAL SPECIMENS AND TYPING OF THEM BY ERIC-PCR METHOD IN IRAN

Background and Aim:The emergence of the plasmid-mediated mcr colistin resistance gene in the community poses a potential threat for treatment of patients, especially when hospitalized. The aims of this study were to search of presence of mcr-1 and mcr-2 genes among colistin resistant Escherichia coli and Klebsiella pneumoniae isolates from clinical specimens and fingerprint determination of the strains by ERIC-PCR.Methods:In this study, 712 non-duplicate Enterobacteriaceae isolates from clinical specimens, were examined. All of the isolates were subcultured on suitable media and the isolated colonies were identified by standard biochemical tests. Antimicrobial susceptibility test to 7 antibiotics were performed by disk diffusion method, and MIC of isolates to colistin were determined by E-test method. These isolates were typed by ERIC-PCR method, and the presence of mcr-1 and mcr-2 genes were investigated by PCR method.Results:Out of 470 isolates, including 351 E. coli and 119 K. pneumoniae isolates were detected. The results of antibiogram test showed that the most isolates (81.3%) were resistante to ceftazidime, however, the most susceptibility (81.5%) to colistin were seen among of isolates. The typing results by ERIC-PCR method showed 6 and 23 fingerprint patterns, respectively for colistin resistant E.coli and K. pneumoniae strains. Among of 64 (8.98%) colistin-phenotypically- resistant Enterobacteriaceae, 8 isolates (1.12%) had mcr-1 gene. Also the mcr-2 gene was not detected.Conclusion:Spreading of entrobacterial strains harboring mcr containing plasmids could fail the colistin included therapy regimen as the last line agent against MDR entrobacterial infections.

کلیدواژه ها:

Enterobacteriaceae ، colistin ، ERIC-PCR ، mcr1 ، mcr-2 genes