Abundance of Mobilized Colistin Resistance Gene ( mcr-1 ) in Commensal Escherichia coli from Diverse Sources.

Antimicrobial resistance (AMR) spreads not only by pathogenic but also by commensal bacteria, and the latter can become a reservoir for resistance genes. This study was aimed to investigate the AMR patterns along with the presence of mobilized colistin resistance () genes in commensal circulating in chickens, farm environments, street foods, and human patients. By a cross-sectional survey, isolates obtained from 530 samples were tested for their AMR profiles against 9 antimicrobials. Minimum inhibitory concentration (MIC) of the phenotypically colistin-resistant isolates was determined and screened for a set of genes followed by sequencing of gene in the multidrug-resistant (MDR) isolates. A total of 313 strains were isolated and confirmed by polymerase chain reaction. Antimicrobial susceptibility testing revealed that about 98% (confidence interval [95% CI] 95-99) of the isolates were MDR, and 58% (95% CI 52-63) isolates exhibited resistance to colistin. MIC values of colistin against the isolates ranged from 4 to 64 mg/L. Except for human patients, 20.4% colistin-resistant isolates from other sources of isolation had gene. There is abundance of commensal MDR strains with the acquisition of gene circulating in chickens and farm environments in Bangladesh.