Evaluation of Antibiotic Resistance Patterns and Enzyme Production Potentials by Bacteria from Two Selected Water Bodies in Ilorin, Nigeria

Abstract

Introduction: Antimicrobial resistance is a global public health problem that threatens the treatment of infections caused by microorganisms because of their increasing resistance. This study determined the resistance patterns and the potential of bacteria isolated from selected surface waters to produce certain enzymes. Methods: Surface water samples were collected from the Asa River and the University of Ilorin River, and bacteria from the composite samples were isolated and identified using standard microbiological techniques. Resistance patterns of the bacteria to conventional antibiotics were determined using the Kirby-Bauer disc diffusion method, and the results were compared with Clinical and Laboratory Standards Institute (CLSI) guidelines. The Multiple Antibiotic Resistance Index (MARI) was evaluated. The ability of bacterial isolates to produce extracellular enzymes (protease, lipase, esterase, or peroxidase) was determined, and selected bacterial isolates were identified molecularly using 16S rRNA gene sequencing. Results: Three different bacterial genera were isolated and identified, including Enterococcus faecium (A1), Shigella sp. (A2), and Streptococcus sp. (A3). Among these, isolate A1 showed the highest resistance at 83.3% (MARI = 0.83). All three bacterial isolates exhibited MARI values greater than 0.20, demonstrating their public health importance. None of the bacterial isolates produced any of the tested enzymes. Molecular identification showed that isolate A1 was Aeromonas dhakensis, with 99.58% genetic similarity; the isolate is recognised as an emerging water-borne pathogen, while isolates B2 and B3 were identified as Jeotgalibaca-like isolates. Conclusion: This study suggests the need for better management of surface waters in dams and rivers as possible reservoirs of antimicrobial-resistant bacteria.