Aim Control of operations of catfish farmers still lacks in Nigeria due to the absence of catfish inspection programmes by relevant regulatory agencies. Thus, this study aimed at performing comprehensive surveillance of Nigerian catfish pisciculture systems so as to provide empirical evidence on the extent of contamination with multidrug-resistant bacteria due to potential abuse of standard operational procedures by catfish farmers. Methods and ResultsConclusionOne-way analysis of variance was performed on pond water and catfish samples which were randomized with the Wei's-Urn randomization modelling technique. Ceftriaxone-selected bacterial colonies isolated from catfish and pond water samples collected from nursery and grow-out pond systems were tested for multidrug resistance. Haemocytotoxigenic and Shiga toxigenic virulence traits in multidrug-resistant colonies, as well as detection of hyper-Ambler class C-(AmpC) beta-lactamase and carbapenemase production, were also performed using phenotypic/molecular methods. Of the 648 ceftriaxone-selected bacterial isolates examined in this study, 515 isolates were found to be multidrug-resistant bacteria, of which 366 isolates were characterized as pathogenic multidrug-resistant bacteria. Both nursery and grow-out ponds had high frequencies of bacterial resistance to ampicillin (86-93%), cotrimoxazole (47-87%) and chloramphenicol (95-100%). However, high frequencies of bacterial resistance to amoxicillin/clavulanic acid (75-83%) were only observed in the grow-out ponds. Also, hyper-AmpC beta-lactamase-producing multidrug-resistant bacteria were only seen in the grow-out ponds. Isolated multidrug-resistant bacteria were confirmed as Enterobacter cloacae, Citrobacter freundii, Bacillus cereus, Pseudomonas aeruginosa, Escherichia coli and Enterococcus faecalis. The findings in this study corroborate the urgent need for some form of international mediation to urge the Nigerian government and her regulatory agencies to commence monitoring of catfish pisciculture operations since multidrug-resistant bacteria could be transmitted to humans. Significance and Impact of the StudyOur study provided empirical evidence that revealed the misuse/abuse of antibiotics during pisciculture operations in Nigeria; thus, constituting these pisciculture systems into reservoirs of multidrug-resistant bacteria.