Oluchi Agbo, Mumuni Momoh, Damian Odimegwu, Cyril Adonu,
Volume 12, Issue 2 (6-2024)
Abstract
Introduction: Hospitals are breeding grounds for multidrug-resistant (MDR) bacteria, posing treatment challenges and increasing the risk of spreading "superbugs." This study investigates the prevalence of colistin-resistant bacteria, a last-resort antibiotic, in wastewater from tertiary hospitals in Enugu, Nigeria. Methods: Twenty wastewater samples were collected over three months from two tertiary hospitals in Enugu. A standardized protocol by the American Public Health Association (APHA) was followed. Samples were collected aseptically from key drainage points and transported to the lab within 2 hours. Bacteria were isolated using the pour-plate method and characterized by morphological and biochemical tests, including Catalase, Oxidase, and Glucose Fermentation. Antibiotic susceptibility was assessed using Kirby-Bauer disc diffusion, and colistin resistance was confirmed via broth microdilution. Multiplex PCR detected mcr genes indicating plasmid-mediated resistance. Data were analyzed using SPSS version 23 with Chi-Square and ANOVA tests at a significance level of P < 0.05. Results: Gram-negative bacteria were isolated from 63.1% of samples, with Klebsiella spp. being the most prevalent, accounting for 24.6%. Colistin resistance was phenotypically observed in E. coli (83%), Klebsiella spp. (75%), and Pseudomonas aeruginosa (100%). Genotypically, E. coli harbored mcr-1 (17%) and mcr-3 (83%), while all Klebsiella and Pseudomonas isolates carried multiple mcr genes. Additionally, these bacteria showed resistance to multiple antibiotics, including Septrin, Gentamycin, and Ceftriaxone. Conclusion: The significant presence of colistin-resistant bacteria, especially E. coli and Klebsiella, poses a public health concern, potentially leading to treatment failures and spreading resistance genes. Stricter monitoring of hospital wastewater is necessary to identify emerging resistance trends and improve antibiotic practices in hospitals.
