Identification of molecular determinants of antibiotic resistance in some fish farms of Ghana

Rosemary Agbeko; Denis W Aheto; Daniel K A Asante; Noble K Asare; Alex A Boateng; Cynthia A Adinortey

doi:10.1016/j.heliyon.2022.e10431

Identification of molecular determinants of antibiotic resistance in some fish farms of Ghana

Heliyon. 2022 Aug 30;8(9):e10431. doi: 10.1016/j.heliyon.2022.e10431. eCollection 2022 Sep.

Authors

Rosemary Agbeko¹, Denis W Aheto^{2

3}, Daniel K A Asante¹, Noble K Asare^{2

3}, Alex A Boateng², Cynthia A Adinortey¹

Affiliations

¹ Department of Molecular Biology and Biotechnology, School of Biological Sciences, University of Cape Coast, Ghana.
² Department of Fisheries and Aquatic Sciences, School of Biological Sciences, University of Cape Coast, Ghana.
³ Centre for Coastal Management (Africa Centre of Excellence in Coastal Resilience), University of Cape Coast, Ghana.

Abstract

Antimicrobial resistance is a global health challenge caused by the ability of microorganisms including bacteria, fungi, protozoans and viruses to survive the effects of drugs that hitherto were effective against them. This study sought to investigate the presence of antibiotic-resistant bacteria and their corresponding molecular determinants in fish farms of the Central and Western Regions of Ghana. Management practices and antibiotic use at the fish farms were obtained through the administration of a questionnaire. Coliform and Gram-positive bacterial loads of catfish (Clarias gariepinus), tilapia (Oreochromis niloticus) intestinal microbiota, and pond water samples recovered on MacConkey Agar and Mannitol Salt Agar were determined. Bacterial isolates were identified using various biochemical assays. Antibiotic resistance profiles and possible responsible genes of bacterial isolates were determined using the disc diffusion and Polymerase Chain Reaction (PCR) methods respectively. The study revealed that none of the fish farm managers admitted using antibiotics for prevention and treatment of diseases and no major disease outbreak had ever been recorded. Bacterial loads of pond water exceeded the acceptable level of ≤100 E. coli and <10 coliforms per mL for wastewater recommended for use in fish farming. In all, 145 bacterial isolates comprising 99 Gram negative and 46 Gram-positive bacteria were stored and identified. Most isolates were resistant to at least an antibiotic. Both Gram-negative and Gram-positive bacteria were highly resistant to beta-lactam antibiotics with a corresponding high percentage detection of the bla _TEM gene compared to other classes of antibiotics. This study has revealed the presence of various molecular determinants of antibiotic resistance including bla _TEM, cmIA, qnrS, tetB and bla _CTX-M, in multidrug-resistant bacteria at some fish farms in Ghana. There is the need to increase awareness about risks associated with the misuse and overuse of antibiotics by humans and the potential risk of spread of multi-drug resistant-bacteria in the environment.

Keywords: Antibiotics; Aquaculture; Coliforms; E. coli; Fish farms; Fish species; Resistance genes.