Colistin: From the shadows to a One Health approach for addressing antimicrobial resistance

Antimicrobial resistance (AMR) poses a serious threat to human, animal, and environmental health worldwide. Colistin has regained importance as a last-resort treatment against multidrug-resistant Gram-negative bacteria. However, colistin resistance has been reported in various Enterobacteriaceae species isolated from several sources. The 2015 discovery of the plasmid-mediated mcr-1 (mobile colistin resistance) gene conferring resistance to colistin was a major concern within the scientific community worldwide. The global spread of this plasmid – as well as the subsequent identification of 10 MCR-family genes and their variants that catalyse the addition of phosphoethanolamine to the phosphate group of lipid A – underscore the urgent need to regulate colistin use, particularly in animal production. This review traces the history of colistin resistance and mcr-like gene identification and examines the impact of policy changes regarding colistin use on the prevalence of mcr-1-positive E. coli and colistin-resistant E. coli from a One Health perspective.