Antibiotic resistance patterns of bacterial isolates from hatcheries and selected fish farms in the Ashanti region of Ghana

Antibiotic resistance has become an increasingly global health problem. This has resulted in a limited number of antibiotics being effective in the treatment of various infections. Antibiotic resistant organisms have been isolated from fish ponds in various studies in different parts of the world. This study was carried out to assess some fish farming practices among catfish and tilapia farmers which may contribute to antibiotic resistance and also to determine the susceptibilities of Staphylococcus aureus, Escherichia coli, Shigella species, Salmonella typhi and Pseudomonas aeruginosa isolated from fish pond water, catfish gut and tilapia gut from 11 farms and two hatcheries to selected reference antibiotics including penicillin, ampicillin, flucloxacillin, erythromycin, tetracycline, sulphamethoxazole/trimethoprim, cefuroxime, gentamicin, ciprofloxacin and chloramphenicol using the disc diffusion method. With the exception of gentamicin and ciprofloxacin, there was varying resistance of more than 60% to the other antibiotics. Most of the bacterial isolates exhibited high resistance (≥70%) to penicillin, ampicillin, flucloxacillin and tetracycline whilst low resistance was observed in all isolates to gentamicin (1.7 to 5.6%) except in P. aeruginosa. 44 to 92.9% of isolates of organisms showed resistance to more than three antibiotics. The bacterial isolates from the sampled fishes exhibited multidrug resistance although there was no recent history of use of antibiotics in most of the farms studied.   Key words: Bacterial isolates, antibiotics, antibiotic resistance, fish farms.