养殖浅色黄姑鱼体表溃烂症病原菌的分离与鉴定

Isolation and identification of a bacterial pathogen from Chu's croaker Nibea coibor

浅色黄姑鱼的高密度养殖一直受到病害的困扰,导致成鱼养殖成活率低,直接影响了浅色黄姑鱼养殖业的发展.以汕头南澳岛患皮肤溃烂症的养殖浅色黄姑鱼为材料,从其溃烂头部组织中分离得到优势菌KLg,人工感染实验证实菌株KLg为浅色黄姑鱼的致病菌.药敏试验表明菌株KLg对头孢哌酮、红霉素、头孢曲松、先锋霉素V、复达欣、头孢呋辛和氧哌嗪青霉素等7种抗生素敏感,革兰氏染色、生理生化测定等手段初步确定菌株KLg为哈维氏弧菌(Vibrio harveyi),这一结果通过16S rDNA基因序列及进化树分析得到进一步确认.哈维氏弧菌是海水养殖鱼类的常见致病菌,但在浅色黄姑鱼养殖中尚属首次报道.实验结果可为我国沿海地区浅色黄姑鱼养殖中弧菌病害的防治提供重要参考.

The usual occurrence of the diseases, which results in high mortality of adult Chu＇s croaker （ Nibea coi- bor）, have a negative effect on the development of high density croaker mariculture. In the present study, the path- ogenic bacteria were isolated from the head of the diseased croaker of Nanao isoland, Shantou, China. A dominant green isolate （named KLg） was retrieved from the croaker. KLg was proved to be the pathogen of the diseased croaker by artificial infection and the drug sensitivity test of KLg showed that the pathogen was sensitive to 7 antibi- otics such as cefoerrazone, erythromycin, ceftriaxone, cefazolin, ceftazidine, cefuroxime and piperacillin. The strain was further confirmed to be affiliated with Vibrio harveyi after gram stain, biochemical test and phylogenetic analysis and reconfirmed by 16S rDNA gene sequence and phylogenetic analysis. To our knowledge, this is the first report that V. harveyi was found to be the pathogen of cultured Chu＇s croaker in southern China. The results here would lay a basis on further disease prevention and remediation of Chu＇s croaker N. coibor in future.