Abstract
This study aimed to identify and evaluate the antibiotic susceptibility of the bacterial pathogen causing hemorrhagic disease in cultured sturgeon (Acipenser baerii) at the nursing stage in A Luoi, Hue city. Bacterial isolates were characterized using biochemical tests (API 20 Strep) and species-specific PCR The results that all isolates were Streptococcus iniae, showing typical characteristics including Gram-positive cocci, negative oxidase and catalase reactions, and hemolytic activity. PCR amplification yielded a specific product of approximately 870bp. Antibiotic susceptibility testing using the disk diffusion method demonstrated that S. iniae isolated from 12 sturgeon disease samples exhibited high sensitive to most tested antibiotics, with inhibition zone diameters ranging from 16,0 to 38,0 mm. The greatest antibacterial activity was observed for Cephalexin (30 µg) and Amoxicillin (10 µg), which produced inhibition zone of 38.0 and 36.0 mm, respectively.