白斑狗鱼(Esox lucius)致病性嗜水气单胞菌的分离与鉴定

Isolation and Identification of Pathogenic Aeromonas hydrophila From Esox lucius Around Urumqi in Xinjiang

近些年来,新疆许多养殖场发生白斑狗鱼暴发性疾病而死亡。为鉴定病因,本研究对乌鲁木齐周边地区的自然患病白斑狗鱼(Esox lucius)的肝脏、肾脏等组织进行分离,经形态观察、生理生化试验、16S r DNA序列分析进行细菌鉴定。并通过人工回归感染白斑狗鱼和鲫,来验证分离菌株的致病性。结果表明,分离出的9株优势菌为致病性嗜水气单胞菌,命名为PK001-PK009。经PCR特异性检测发现,所得的9个菌株分别含有丝氨酸蛋白酶基因(ahp A)、溶血素基因(hly A)和气溶素基因(aer A)中的0-3个,从而导致了菌株间致病性的差异。通过人工回归感染实验发现,白斑狗鱼患病症状与自然病例相似,并重新分离得到原感染菌,经细菌学鉴定,其性状与原菌株一致,为嗜水气单胞菌。

Northern pike （Esox lucius）, one of the major indigenous economic fish in Xinjiang, belongs to the ferocious carnivorous cold-water fish family. With the fast development of artificial breeding, disease outbreak has raised. The outbreak of bacterial sepsis is one of the dominant diseases to Northern pike farming, causing huge economic losses in local aquaculture. In order to identify the etiology of the Northern pike, the liver and kidney samples of Northern pike were collected for the morphology observations, physiological and biochemical tests, and 16S rDNA sequence analysis. Nine dominant bacteria were separated, which belong to the Aeromonas hydrophila family （named PK001-PK009）. The PCR specificity detection results indicated that the separated nine strains contained three mainly and widely studied virulence factors of A.hydrophila ahpA, hlyA and aerA with the frequency from zero to three, which leaded to the discrepancy of strains. The illness of artificial recurrent infection and natural case of E. lucius were similar, and the origin infection bacteria were separated and further confirmed with A. hydrophila infection. A. hydrophila is the main pathogenic bacteria that induce fish bacterial sepsis.