Determination of <i>MCR-1</i> Gene and Antibiotic-Resistant <i>Escherichia coli</i> Isolates from Clinical and Non-clinical Samples

In recent years, resistant infections and antibiotic resistance in livestock have been increasing, and it seems that these issues will cause more problems in the future.

This study investigates the association between the pattern of Escherichia coli antibiotic resistance (ECAR) and the identification of the mobilized colistin resistance ( mcr-1 gene) among clinical and non-clinical samples.

In this study, 265 samples were collected from clinical (human urine, N = 79) and non-clinical sources (animal feces from poultry and livestock farms, N = 186). All samples were processed, and E. coli bacteria were isolated and identified. The agar dilution method was used to evaluate colistin resistance, and the presence of the mcr-1 gene was characterized among E. coli isolates.

Out of 265 samples (clinical and fecal), 37.97% (30/79) of clinical samples and 37.63% (70/186) of animal feces showed growth of E. coli . The highest number of E. coli isolates was found in feces from livestock farms (71.48%; 50/70). Antimicrobial susceptibility testing (AST) of E. coli isolated from clinical samples showed that the highest resistance (46.66%) was to ciprofloxacin, and the lowest resistance (16.66%) was to colistin . Analysis of polymerase chain reaction (PCR) data also showed that 60% of colistin -resistant isolates from clinical urine samples and 70% from animal feces samples were positive for the plasmid-mediated mcr-1 gene.

The findings indicate that the high frequency of the mcr-1 gene among both clinical and animal-collected isolates may be a significant factor in the development of colistin resistance among circulating E. coli isolates.