Research progress on the plasmid-mediated colistin resistance gene mcr-1.

mcr-1, the first plasmid-mediated colistin-resistance gene, can mediate polymyxin resistance and be transferred horizontally via plasmids. Many studies have confirmed its distribution via epidemic plasmids (IncI2, IncX4, IncHI2, etc.), as well as mobile genetic elements, among Enterobacteriaceae isolated from animals, humans, and the environment in 35 countries. These studies provide the basis of understanding the complicated mechanism of colistin resistance mediated by MCR-1 and its global dissemination and epidemic properties, and also enrich antimicrobial resistance mechanisms. Here, we review the latest advances in the prevalence, resistance mechanism, transfer mechanism, and genetic environments of mcr-1 in isolates recovered from various samples worldwide. Finally, we discuss the clinical risk and the corresponding solutions, aiming to provide a basis for researchers and clinical scientists to face the serious challenge of antimicrobial resistance together.