First time isolation of Photobacterium damselae subsp. damselae from Caranx sexfasciatus in Persian Gulf, Iran

BACKGROUND AND OBJECTIVE: Photobacterium damselae subsp. damselae is a marine pathogenic bacterium which causes disease in marine animals and human. This bacterium mostly found in coastal shallow seawater. So, the aim of this study was isolation and characterization of Photobacterium damselae subsp. damselae from edible fish of Persian Gulf, Bandar Abbas. MATERIAL AND METHODS: Totally 100 fish from different species were evaluated and out of that 5 different types of fish with external symptoms including: Caranx sexfasciatus, Lethrinus olivaceus, Scomberoid tol, Auxis thazard and Liza macrolepis, were collected from Bandar Abbas local fish market in September 2013. The samples were cultured on Marin Agar 2216 and Thiosulfate Citrate Bile salts Sucrose Agar media and incubated at 25°C for 48 hrs. Then the isolates were characterized using biochemical (API 20 NE system) and molecular techniques. In addition, antibiotic susceptibility, presence of poly β hydroxy butyrate and hemolysis activity of isolates were evaluated. RESULTS AND CONCLUSION: Entirely, 30 Gram negative bacterial colonies were isolated from the selected fish. Among the isolates, two suspected colonies were identified as Photobacterium damselae from Caranx sexfasciatus with API 20NE biochemical test. This results confirmed by 16s rRNA sequencing method. Both isolates showed α hemolytic with existence of β hydroxyl butyrate. Furthermore, the isolates were susceptible to ciprofloxacin, chloramphenicol and nalidixic acid. CONCLUSION: Overall, the study indicated first time isolation of this bacterium from one type of fish caught from Persian Gulf, which warns us to pay more attention to fishery in this geographical area.