Molecular and biochemical identification of Phototobacterium damselae isolated from diseased golden pompano in Khánh Hòa

Abstract

Hemorrhagic septicemia and skin ulcers in golden pompano (Trachinotus spp.) are common syndromes that significantly impact aquaculture productivity. This study aimed to isolate and identify bacteria suspected to be the causative agents in cage-cultured pompano exhibiting hemorrhagic septicemia and sporadic mortality in Khanh Hoa. Gram-negative, short rod-shaped bacteria were observed and isolated from the internal organs of diseased fish. A total of six bacterial strains with similar colony morphology were obtained on Nutrient Agar, TCBS, and Hicrome™ Vibrio agar. Biochemical characterization using the API 20E system showed that all isolates had identical profiles of P. damselae subsp. damselae. Species-specific PCR amplification of the ureC gene produced ~448 bp products in all isolates, matching the positive control using DNA from P. damselae. The results confirm that all bacterial isolates from diseased pompano are P. damselae subsp. damselae. These findings provide a basis for further studies on the virulence and pathogenicity of this bacterium in golden pompano in Việt Nam.

DOI: https://doi.org/10.53818/jfst.03.2025.562