Prevalence of mcr-1 in commensal Escherichia coli from French livestock, 2007 to 2014

Abstract : Colistin resistance was investigated in 1,696 isolates collected from 2007 to 2014 within the frame of the French livestock antimicrobial resistance surveillance programme. The mcr-1 gene was detected in all com-mensal Escherichia coli isolates with a minimum inhibi-tory concentration to colistin above the 2 mg/L cutoff value (n=23). In poultry, mcr-1 prevalence was 5.9% in turkeys and 1.8% in broilers in 2014. In pigs, investigated in 2013, this prevalence did not exceed 0.5%. These findings support that mcr-1 has spread in French livestock. We report mcr-1 prevalence data in commensal Escherichia coli isolated from French livestock from 2007 to 2014.