海洋蛭弧菌的分离鉴定及其对副溶血弧菌的作用

Isolation, Identification of Marine Bdellovibrios and Its Effect on Vibrio parahaemolyticus

蛭弧菌广泛存在于自然水体,具有噬菌的特性,对水体中细菌数量控制具调节作用。以副溶血弧菌为宿主菌,利用双层琼脂法,从海洋水体中分离出15株具有噬菌作用的细菌,对形成噬菌斑能力最强的1株菌株进行特异性16SrDNA扩增,确认为蛭弧菌,命名为Bd-M1。Bd-M1对大多数海水养殖动物病原菌有裂解作用,裂解率在90%(20/22)以上,模拟水环境实验发现,蛭弧菌对副溶血弧菌有较强的裂解和净化作用,102h内能使副溶血弧菌从3.0×108CFU/mL下降到8.7×103CFU/mL。动物实验表明蛭弧菌能有效预防对虾弧菌病的发生,表明蛭弧菌有望成为水产动物疾病防治的一种有效的生物制剂。

Bdellovibrios are obligate predatory bacteria, widely distribute in nature and regulate the counts of bacterium in water. Fifteen strains of predatory bacteria were isolated from marine environment using Vibrio parahaemolyticus DX-1 as host and one of them formed large plaques designated as Bd-M1. The strain was confirmed by Bdellovibrio species-specific 16S rDNA fragment amplified using PCR method. Deterruination of host range on species of fish pathogenic bacteria （Vibrio parahaemolyticus, Vibrio alginolyticus, Vibrio anguillarum, Vibrio anguillarum, Vibrio vulnificus and Edwardsiella tarta） indicated that Bd-MI was able to parasitize 20 strains out of a total of 22 tested. Co-culture experiment shown that Bd-M1 have purifi- cation function on Vibrio parahaemolyticus, the number of V. parahaemolyticus decreased from 3.0×10^8 CFU/mL to 8.7×10^3 CFU/mL during 102 h. Immersion Penaeus vannamei in water at different concentration of Bd-M1 was used in protection against experimental infection with V. parahaemolyticus DX-1 infection. Results shown that the mortality of groups bathed with Bd-M1 was lower than that group without Bd-M1. These results suggest that it may be possible to use bdellovibrio to control fish disease.