Emergence of colistin-resistant Enterobacter cloacae and Raoultella ornithinolytica carrying the phosphoethanolamine transferase gene, mcr-9 , derived from vegetables in Japan

Plasmid-mediated mobile colistin-resistance genes have been recognized as a global threat because they jeopardize the efficacy of colistin in therapeutic practice. Here, we described the genetic features of two -carrying Gram-negative bacteria with a colistin-resistant phenotype derived from vegetables in Japan. The colistin-resistant , which has never been detected in vegetables, was located on a large plasmid in CST17-2 and CST129-1, suggesting a high chance of horizontal gene transfer. To the best of our knowledge, this is the first report of in . This study indicates that fresh vegetables might be a potential source for the transmission of genes encoding resistance to frontline (colistin) and clinically relevant antimicrobials. The study also provides additional consideration for colistin use and the relevance of routine surveillance in epidemiological perspective to curb the continuous spread of alleles.