Prevalence and Antibiotic Susceptibility Profiles of Klebsiella spp. in African Catfish (Clarias gariepinus) in Maiduguri, Borno State, Northeastern Nigeria

Abstract

The emergence and spread of antibiotic-resistant bacteria in aquatic systems presents a growing threat to public health, food safety, and sustainable fish farming worldwide. This study investigated the prevalence and antibiotic susceptibility profiles of Klebsiella species isolated from African catfish (Clarias gariepinus) in Maiduguri, Borno State, Northeastern Nigeria. A total of 300 catfish samples were randomly collected from three major markets, and both skin and intestinal specimens were analysed using standard microbiological and biochemical methods. Klebsiella spp. were detected in 50% of all samples, with a significantly higher prevalence in intestinal samples (72%) compared to skin samples (28%) (p< 0.001), while no significant differences were observed across market locations. Antibiotic susceptibility testing using the Kirby–Bauer disc diffusion method revealed high sensitivity to ofloxacin (99.3%), streptomycin (96.0%), and chloramphenicol (95.3%), but moderate susceptibility to ampicillin, ciprofloxacin, and nalidixic acid. Alarmingly, all the isolates were resistant to amoxicillin–clavulanic acid, and over 90% were resistant to pefloxacin, indicating that the pathogen has developed substantial resistance to these agents. Multi-drug resistance (MDR) was present in 20% of isolates, with some exhibiting resistance to up to seven antibiotics. These results highlight the widespread presence of Klebsiella and multi-drug resistance in catfish, reinforcing public health concerns and the need for improved antibiotic management and surveillance in aquatic environments.