Detection of Antibiotic-Resistant <i>Klebsiella </i>Sp<i>.</i> from the Wupa River and Wastewater Treatment Plant, F.C.T Abuja

Abstract

Antimicrobial resistance (AMR) is a global health crisis that undermines the effectiveness of antibiotics in treating infections, posing a threat to humans and animals. Antibiotics are not fully metabolized by humans or animals, leading to their dispersion within sewage streams. The dissemination of antibiotic-resistant bacteria in aquatic environments poses a significant public health risk, particularly through the release of treated wastewater into natural water bodies. This study investigated the presence of Antibiotic Resistance Genes (ARGs) in Klebsiella sp. isolates collected from four sampling points along the Wupa River and its wastewater treatment plant (WWTP): Upstream (P1), Influent (P2), Effluent (P3), and Downstream (P4). Physicochemical analyses of water samples showed that most parameters, including temperature, pH, total dissolved solids, dissolved oxygen, and nitrates, stayed within WHO-recommended limits. However, phosphates, total suspended solids, and ammoniacal nitrogen consistently exceeded these limits at all sites. The highest levels of biochemical oxygen demand (BOD), soluble chemical oxygen demand (COD), and total COD were found at the influent. The Total Viable Count carried out for bacterial colonies and Klebsiella colonies to assess microbial load showed the highest value at the 10^ (- 2) dilution factor and the lowest at the 10^ (- 5) dilution factor. Isolation and identification of Klebsiella spp. were performed using biochemical tests, including Voges-Proskauer (+), Indole (-), Citrate (+), Urease (+), Methyl red (-), Triple Sugar Agar (+), and Gram staining, revealing Gram-negative rods. Molecular analysis detected amplification of key resistance genes sul2, tetB, blaTEM, and blaCTX. Amplification of tetB gene in both influent and effluent samples indicates incomplete removal of tetracycline resistance genes during wastewater treatment. The blaTEM and blaCTX genes were detected across all sampling points, suggesting widespread environmental dissemination and potential contamination sources beyond the WWTP. These findings highlight the persistence and spread of multidrug-resistant Klebsiella in riverine and wastewater environments, underscoring the critical need for improved wastewater treatment strategies and continuous monitoring to mitigate the public health impact of antibiotic resistance in aquatic ecosystems.