Bacteriological Quality and Antibiotics' Susceptibility Profile of Small-medium Scale Commercial Fish farms in Nigeria

Fish currently provide 6.7% of all proteins consumed by humans globally; nevertheless, the aquaculture system has been linked to fish, environmental contamination and disease outbreak. The aim of this study was to determine the bacteriological quality and the antibiotic resistance profile of bacteria from water samples of pond stocked with Tilapia and Catfish in Ile-Ife, Osun State, Nigeria.

To isolate, identify and characterise heterotrophic bacteria and test for the antibiogram of detected Coliforms.

Water samples were collected from ponds stocked with Tilapia and Catfish, and tested for total heterotrophic and coliform bacteria as well as the antibiogram. The susceptibility of the isolates was tested using the Kirby-Bauer disc diffusion method on Mueller Hinton agar.

A total of 40 isolates were recovered from the water samples, of which 5 species were Gram positive bacteria representing two genera, and 35 species were Gram negative bacteria representing four genera. The temperature for all ponds ranged from 25°C to 28°C. The mean bacterial count varied from 1.9×10⁴ to 5.4×10⁴ CFU/ml per fish pond. All isolates were 100% resistant to ceftazidime, cefuroxime and augmentin. More resistance to cefixime (80%) and gentamicin (73.3%) and nitrofurantoin (66.7%) was also recorded. However, only 16.6% and 8.3% of the isolates were resistant to ciprofloxacin and ofloxacin, respectively. The multiple antimicrobial resistance index (MARI) ranged from 0.5 to 0.9. The water physicochemical parameters (temperature and pH) and the type of bacteria detected in all pond types did not differ significantly.

Fish pond is a reservoir of multi-drug resistant bacteria that could serve as environmental source of drug resistance gene transfer. This calls for effective monitoring and assessment as well as management devices for the protection of community and environmental health.