mcr-1 is borne by highly diverse Escherichia coli isolates since 2004 in food-producing animals in Europe.

Abstract

International audienceIn November 2015, a plasmid-mediated colistin resistance, MCR-1, was described in animals, food and humans in China, and it was considered as a potential emerging threat to public health. Therefore, we screened for the mcr-1 gene a European collection of colistin-resistant Escherichia coli (n=218) and Salmonella spp. (n=74) isolated from diseased food-producing animals between 2004 and 2014 and characterized the mcr-1-positive clones.Screening for mcr-1 gene was performed by PCR on isolates for which inhibition diameter was 2 mg/L. Most of the mcr-1-positive E. coli belonged to the phylogroup A with two prevalent clonal complexes, CC10 and CC165, in which sequence type 10 and sequence type 100 were overrepresented and pulsed-field gel electrophoresis typing revealed a high diversity of pulsotypes.MCR-1 was detected yearly in European food-producing animal since 2004 with a high diversity of pulsotypes supporting the dissemination of mcr-1 via plasmids