Audacious Hitchhikers: The Role of Travel and the International Food Trade in the Global Dissemination of Mobile Colistin-Resistance ( mcr ) Genes.

Colistin, a last-resort antibiotic, has been used in controlling infections caused by multidrug-resistant Gram-negative bacterial pathogens. However, recent reports showed a global dissemination of mobile colistin-resistance(mcr) genes, genetic elements that encode resistance to colistin, which has raised public health concerns. Thesemcrgenes threaten the effectiveness of colistin and could limit therapy options for complicated infections. Despite global attention, many facets of the molecular epidemiology ofmcrremain poorly characterized. Here, we focus on the role of travel and the international food trade in the dissemination ofmcrto countries where these genetic elements and/or colistin resistance are relatively limited in prevalence. We present evidence from the literature on the acquisition ofmcrduring travel, and the carriage of these genes back to travelers' countries. We also highlight the potential transmission ofmcrvia imported foods. These observations emphasize the magnitude of efforts that are needed to control the spread ofmcr,and further highlight the challenge of antimicrobial resistance and the urgent need for coordinated global action.