Detection and Phenotypic Characterization of Colistin-Resistant Bacteria in Water

Background and Objective: The emergence and dissemination of colistin-resistant Gram-negative bacteria strains are becoming a major global risk to human health, as colistin is one of the last-line antimicrobial agents against life-threatening infections. Thus, this study aimed at investigating the prevalence of colistin-resistant bacteria in various water sources. Materials and Methods: Samples were collected from taps connecting boreholes, stored rainwater, water distributors, or Ghana water company limited within Danfa, Otinibi and Cite-C, as well as from the Ayensu River. A total of 200 samples were collected from 5 different water sources, tap water (36 samples), borehole (96 samples), river (20 samples), rainwater (20 samples) and water distributors (28 samples). Results: A total of 200 water samples were collected from different sources with 46 aerobic Gram-negative bacteria isolated. Klebsiella species were the most isolated organism with Serratia marcescens being the least isolated. The 46% of the Gram-negative bacteria isolated were identified as resistant to colistin with minimum inhibitory concentration (MIC) results >2 µg mL‾¹, while 54% were sensitive to colistin. Conclusion: Almost half of the organisms isolated during this study were resistant to colistin and a majority of these resistant organisms were obtained from borehole water samples. The prevalence of colistin-resistant bacteria was high in this study.