The Emergence and Dissemination of the Mobile Colistin Resistance (mcr) Genes in Humans, Animals, and Environments Across the Middle East and North Africa (MENA) Region

Colistin, a last-resort antibiotic, has been used in human medicine for treating infections with recalcitrant multidrug-resistant Gram-negative bacteria. However, the unregulated use of colistin in agricultural and clinical settings has accelerated the emergence and global spread of the mobile colistin resistance (mcr) genes. While mcr genes have been reported in different matrices globally, data from the Middle East and North Africa (MENA) region remain limited or absent for many countries. This knowledge gap is problematic, because conflict, overcrowding, weak regulatory frameworks, and hosting some of the world’s largest multicultural religious gatherings might collectively create conditions that amplify and spread mcr across the MENA region and beyond. Several countries in the MENA region, particularly Egypt, Lebanon, Algeria, and Tunisia, have reported different mcr genes across multiple matrices. Many mcr-positive isolates were also resistant to multiple other antibiotics and co-carried additional antibiotic resistance genes (ARGs), including those encoding extended-spectrum β-lactamases and carbapenemases. Moreover, mcr has been detected in different bacterial hosts with diverse sequence types and on various plasmid backbones. In this narrative review, we comprehensively compiled, summarized, and analyzed all available reports on mcr in the MENA region, focusing on major online search engines and databases. Our objectives were (i) map the molecular epidemiology of mcr, (ii) highlight the need for better antimicrobial stewardship programs, and (iii) emphasize the importance of implementing integrated national and regional One Health action plans. We also discuss the need for robust surveillance efforts that extend beyond clinical settings to better understand and mitigate the spread of mcr.