Journal of Veterinary and Applied Sciences

Abstract
Rapid expansion in aquaculture has exacerbated the threat of antimicrobial resistance (AMR) especially in sub-Saharan Africa, amid limited surveillance. This study determined the prevalence of antimicrobial resistant Escherichia coli in fresh water catfish (Clarias gariepinus) sampled in Nsukka Nigeria, and further evaluated risk factors associated with its spread, using a One Health approach. The study was a cross-sectional survey. A total of 265 swab samples comprising 150 from raw catfish and 115 from handlers and contact surfaces were processed for E. coli identification using standard techniques. The AMR profile of the isolates were assessed using both disc diffusion and agar dilution methods, while the associated risk factors among fish farmers and processors (n = 150) were assessed with questionnaires. Results showed that the prevalence of E. coli was 11.3% in the sampled catfish, with E. coli contamination rates of 24.3%, 8.6% and 4.7% at restaurants, markets, and fish ponds respectively. The prevalence in handlers’ hands and contact surfaces were 11.4% and 11.2% respectively. The E. coli prevalence rates were significantly (p < 0.05) associated with the source of the fish (ponds, markets or restaurants/hotels). E. coli isolates resistant to antimicrobial agents were 13 (4.9%) of the 265 total samples. Forty percent of the isolates were resistant to erythromycin, while only 3% were resistant to colistin. All the isolates (100%) were sensitive to ciplofloxacin, gentamicin and ceftriaxone. Identified risk factors for the spread of antibiotic resistant E. coli in catfish and catfish handlers in Nsukka Nigeria included: Lack of AMR awareness (75 – 80%), use of antibiotics without prescription (60%), and non-adherence to antimicrobial withdrawal periods (60%). It was concluded that catfish in Nsukka Nigeria is contaminated with antimicrobial resistant E. coli, with post-harvest environments and handlers serving as critical hotspots for its spread, hence the need for urgent interventions, including awareness campaign on antimicrobial stewardship and improved food hygiene practices.

Keywords: Escherichia coli; Prevalence; Catfish; Nsukka Nigeria; Antimicrobial resistance; One Health.

How to cite this article:
Nwankwo IO, Nwobi OC and Kanu DC (2026). Prevalence of antimicrobial-resistant Escherichia coli in freshwater catfish (Clarias gariepinus) sampled in Nsukka Nigeria, and risk factors for its spread. Journal of Veterinary and Applied Sciences, 16(1): 1353 – 1365.

*Correspondence: E-mail: innocent.nwankwo@unn.edu.ng Phone: +2348036202116