GENETICS OF AQUATIC ORGANISMS, vol.6, no.1, pp.95-101, 2022 (Peer-Reviewed Journal)
This study investigated the bacteria present in natural and cultured fish species from
the same aquatic system, and difference of their antibiotic resistance. A total of 129
fish, Georgian shemaya (Alburnus derjugini), black sea salmon (Salmo labrax) and
rainbow trout (Oncorhynchus mykiss), were sampled on a monthly basis between the
months of October 2016 and September 2017 in Kürtün Dam Lake. A total of 41
bacterial isolates were isolated from the fishes. The bacterial species were identified
by molecular methods (PCR) using universal primers for bacteria. Acinetobacter lwoffii,
Acinetobacter sp., Aeromonas sobria, and Pseudomonas sp. were isolated from both
wild and cultured fish. Yersinia ruckeri was isolated from cultured fish, which showed
severe mortality rate and typical symptoms. Various antibiotics including ampicillin
(AMP10µg), gentamicin (CN10 µg), oxytetracycline (T30 µg), amoxicillin/clavulanic acid
(AMC10µg), enrofloxacin (ENR5µg), trimethoprim/sulfamethoxazol (TMP-SMZ25µg),
florfenicol (FFC30µg), sulfamethoxazol (SMZ25µg) and erythromycin (E15µg) were
used for determination of the bacterial resistances. The highest resistances were
determined against ampicillin (56%), sulfamethoxazol (46.3%) and oxytetracycline
(34.1) in all bacterial isolates. While the bacteria isolated from wild fish did not show
resistance to enrofloxacin and amoxicillin/clavulanic acid, those from cultured fish did
not show resistance to gentamicin and erythromycin.