Determining bacterial pathogens in striped catfish (Pangasianodon hypophthalmus) caused hemorrhagic muscle rotting disease

Abstract

The study was carried out to learn about the bacterial pathogen in striped catfish (Pagasianodon hypophthalmus) in order to provide information for effective diagnosis, prevention and treatment of this bacterial species caused diseases on striped catfish. A total of 127 striped catfish samples were collected in Dong Thap province from 1/2023 to 7/2023, of which there were 97 diseased fish samples and 30 healthy fish samples. The individual average weight of diseased fish samples was about 584.8g/fish and an average length was about 32.3cm/fish. Striped catfish with hemorrhagic flesh-rotting disease had typical pathological signs, such as: the muscle tissue at the site of the skin peeling were often swollen, soft, necrotic and putrefied. The liver, kidneys and spleen hemorrhage were soft, and the abdominal cavity contained red fluid. Results of bacterial isolation from 97 diseased fish samples obtained 82 bacterial strains. Bacterial strains isolated from necrotic muscles accounted for 22.0%, up to 30.5% and 32.9% of bacterial strains isolated from liver and kidney, respectively. The results of bacterial identification showed that the bacterial strains isolated from hemorrhagic flesh-rotting diseased striped catfishs were Aeromonas dhakensis. In this study, the A. dhakensis strains were sensitive to doxycycline, colistin, flumequine (76%), levofloxacin (72%), rifampin and norfloxacin (60%).