The exponential increase and impact of aquaculture production systems on the global supply of fish have been confronted with an increase in diseases and antimicrobial use, hence presence of antimicrobial resistance and antibiotic residues in aquaculture. The prevalence, antibiogram, and antibiotic-resistant genes of Vibrio cholerae isolated from apparently healthy farmed Clarias gariepinus were assessed in one hundred and twenty-seven (127) adult fish and thirty-nine (39) fingerlings. A total of four hundred twenty (420) samples comprising 381 organs and 39 fingerlings were analysed. Tissue samples were enriched in peptone water and later cultured using Thiosuifate Citrate-Bilesalts Sucrose (TCBS) media (Millipore®, Germany) and incubated at 30? for 24 hours after which biochemical characterisation was carried out for detailed identification. Fourteen (14) representative isolates were selected for Antibiotic Sensitivity Test (AST), and Antibiotic Resistant Genes (ARGs) determination using polymerase chain reaction.
A total of one hundred and eighty-two Vibrio cholerae organisms were isolated which translated to 11.6% prevalence. All the Vibrio cholerae isolates (100%) were susceptible to Chloramphenicol (C), Tetracycline (TE), and Florfenicol (FFC). 88.9% susceptibility to Kanamycin (K), and 77.8% to Ampicillin (AP), Streptomycin (S), and Trimethoprim/Sulfamethoxazole while they were 100% resistant to Nitrofurantoin (Ni), and Oxytetracycline, 88.9% resistant to Colistin sulphate (CO), Nalidixic acid (NA), and Novobiocin (NB). Out of the fourteen (14) ARGs considered, 88.9% of the isolates possessed Sul-1 resistant gene, 55.6% had Sul-2 and TetB, 33.3% possessed TEM, 22.2% possessed APH-3 and TetH, 11.1% possessed CTX resistant gene while CMY-1, CMY-2, MCR-1, MCR-2, Sul-3, TetA, and ermF resistant genes were absent.
The presence of Vibrio cholerae, a zoonotic pathogen in a fish culture environment has public and environmental health implications for the AMU/AMR menace. The presence of Antimicrobial Resistance characteristics and acquisition of antibiotic-resistant genes in the Vibrio cholerae isolates suggests a significant abuse of antimicrobial agents by the farmers. This also renders the fish and fish products unwholesome and portends grave public health risk. A one-health strategy to sustainable aquaculture development in Nigeria, including biosecurity measures and adequate oversight by competent authorities is hereby recommended.
Keywords: Vibrio cholerae, Antibiotic Resistant Genes, Antimicrobial Resistance, Clarias gariepinus, One-Health strategy, Aquaculture