Chromosome-Mediated <i>mcr-3</i> Variants in Aeromonas veronii from Chicken Meat

Abstract

Two adjacent colistin resistance gene variants, termed <i>mcr-3.3</i> and <i>mcr-3</i>-like, were identified in the chromosome of an <i>Aeromonas veronii</i> isolate obtained from retail chicken meat. The variants showed 95.20% and 84.19% nucleotide sequence identity, respectively, to <i>mcr-3</i> from porcine <i>Escherichia coli</i> Functional cloning indicated that only <i>mcr-3.3</i> conferred polymyxin resistance in both <i>E. coli</i> and <i>Aeromonas salmonicida</i> The <i>mcr-3.3-mcr-3</i>-like segment was also observed in other <i>Aeromonas</i> species, including <i>A. media</i>, <i>A. caviae</i>, and <i>A. hydrophila</i>.