Detection and Dissemination of MCR-1 Colistin Resistance Gene in a Hospital Setting in Abakaliki, Nigeria

Abstract

Background and Objective: Colistin is a last-line antibacterial agent used in clinical medicine.In this study, the dissemination of bacteria harbouring mcr-1 colistin resistance genes in a hospital setting was investigated.Materials and Methods: A total of 500 clinical samples from urine, wound, High Vaginal Swab (HVS), sputum and stool were bacteriologically investigated for the isolation and identification of Gram-negative bacteria including Escherichia coli, Klebsiella pneumoniae and Pseudomonas aeruginosa using standard microbiology techniques.The isolated bacteria were further screened for colistin resistance phenotypes and the detection of the colistin resistance gene, mcr-1 gene using the Polymerase Chain Reaction (PCR) technique.Results: Colistin resistance was phenotypically detected in E. coli isolates from urine (8.2%), wound (4.8%), HVS (4.6%), stool (2.6%), sputum (1%), K. pneumoniae from urine (2.8%), HVS (3.6%), stool (2.2%), sputum (3.8%), and P. aeruginosa from urine (2%), wound (3.8%), stool (1%), sputum (1.6%).Among the colistin-resistant isolates of E. coli, K. pneumoniae and P. aeruginosa, only 1 (0.6%) E. coli isolate and 2 (3.2) isolates of P. aeruginosa harboured the mcr-1 gene.None of the colistin-resistant K. pneumoniae isolates was confirmed by PCR to carry the mcr-1 gene that mediates bacterial resistance to colistin.Conclusion: The growing prevalence of colistin resistance in bacteria warrants urgent steps to preserve the therapeutic efficacy of this antibacterial agent.This study points to the likely spreading of bacteria harbouring the mcr-1 gene in hospitals.The resistance of bacterial pathogens to colistin and other antibacterial agents could jeopardize antibiotic therapy if left unchecked.