Prevalence and Molecular Characterization of Colistin Resistance in Gram-negative Bacteria from Nigeria Hospitals: A Systematic Review

Antibiotic resistance over the years, has emerged as a significant global public health problem, driven by the speedy adaptation of microorganisms to commonly prescribed antibiotics. Colistin, previously regarded as a last-resort antibiotic for treating infections caused by Gram-negative bacteria, is increasingly becoming resistant due to chromosomal alterations and the acquisition of resistance genes carried by plasmids, particularly the mcr genes. The mobile colistin resistance gene (mcr-1) was first discovered in E. coli from China in 2016. Since that time, studies have revealed that different variants of mcr genes ranging from mcr-1 to mcr-10, mainly in Enterobacteriaceae from various parts of the world, which is a focal concern for public health. The co-presence of colistin-resistant genes with other antibiotic resistance determinants further conspire to frustrate treatment strategies and underscores the urgent need for enhanced surveillance and antimicrobial stewardship efforts. Therefore, a good grasp of the mechanisms driving colistin resistance and monitoring its global prevalence are essential steps in addressing the growing threat of antimicrobial resistance and preserving the efficacy of existing antibiotics. This review emphasizes the critical role of colistin as a last-choice antibiotic, elucidates the mechanisms of colistin resistance and the dissemination of resistant genes. It also explores the global prevalence of mcr genes, and evaluates the current detection methods for colistin-resistant bacteria. The objective is to shed light on these key aspects with strategies for combating the growing threat of resistance to antibiotics.