Conjugative IncX1 Plasmid Harboring Colistin Resistance Gene mcr-5.1 in Escherichia coli Isolated from Chicken Rice Retailed in Singapore

Colistin is regarded as one of the last-resort antimicrobials for treatment of Gram-negative bacterial infections (1). Several cases of plasmid-borne colistin resistance genes mcr-1, mcr-3-like, and mcr-4.2 in clinical Enterobacteriaceae isolates, including Escherichia coli, have been reported in Singapore (2-4). However, the mcr-5 gene has not been reported in clinical isolates in Singapore. Previously, we reported the antimicrobial resistance (AMR) genotype and phenotype of E. coli SGEHI2010ENV103 isolates from ready-to-eat food in Singapore and documented the first isolate carrying mcr-5.1 in Singapore (5). In this study, we further analyzed this isolate. Here, we report the first complete nucleotide sequence of a transferable plasmid harboring mcr-5.1 in E. coli isolated from ready-to-eat chicken rice in Singapore. (Chicken rice is a common dish in Singapore which is composed of cooked chicken and seasoned rice, served with sauce and cucumber garnishes). © 2019 American Society for Microbiology. All Rights Reserved.