对虾养殖池中一株弧菌拮抗菌的分离鉴定

Isolation and Identification of a Bacterial Strain with Vibrios-Antagonism from Shrimp Ponds

从对虾养殖池中分离出1株编号为2013082515（简称菌株15）的菌株,以鳗弧菌（Vibrio anguillarum）、哈维氏弧菌（Vibrio harveyi）和副溶血弧菌（Vibrio parahaemolyticus）为指示菌,分析了菌株15对指示菌的抑菌效果及最低抑菌浓度,同时,分析了菌株15对其他7株弧菌的抑菌效果。结果显示,菌株15对3株指示菌均具有抑菌效果,对鳗弧菌、哈维氏弧菌及副溶血弧菌的最低抑菌浓度分别为2.50×10^4、2.50×10^5、2.50×10^5 CFU/ml;对其他弧菌也具有一定的抑菌效果。采用注射及浸泡感染方法分析了菌株15对对虾的生物安全性,结果显示,在高浓度时,菌株15对对虾具有潜在毒性。分别用细菌全细胞脂肪酸气相色谱法和16S rDNA序列分析比对法对该菌进行分类鉴定,表明菌株15为一株假交替单胞菌（Pseudoalteromonas sp.）。

Vibrios were common microbe in marine aquaculture. Most of them such as Vibrio anguillarum, V. harveyi and V. parahaemolyticus etc. were opportunistic pathogen to aquaculture animals. In the latest years, shrimp culture worldwide was subjected to heavy economic loss which was caused by V. parahaemolyticus infection. In order to find a high effective and safety method to control the serious shrimp vibrio disease, instead of using antibiotics, screening and using probiotics is a promising way. In this study, a strain was isolated from a shrimp pond and designated as 2013082515 （Strain 15）. The antibacterial effect and minimum antibacterial concentrations of Strain 15 were analyzed using K anguillarum, V. harveyi and V. parahaemolyticus as indicator bacteria. At the same time, the antibacterial effect of Strain 15 against other seven marine vibrios including V. vulnificus, V. alginolyticus, V. diabolicus, V. campbellii, V. natriegens, V. brasiliensis and V. rotiferianus was analyzed. Biological safety evaluation test on Strain 15 used as probiotic was conducted by injection and immersion challenge. The results showed that Strain 15 had obvious antibacterial effect against three indicator bacteria. Furthermore, the strongest antibacterial effect presented on V. anguillarum with an inhibition zone around （34.90±0.36） mm, the second largest inhibition zone presented on V. harveyi around （25.74±0.17） mm; The minimal inhibitory concentration of Strain 15 on V. anguillarum, V. harveyi and V. parahaemolyticus was 2.50×10^4 CFU/ml, 2.50×10^5 CFU/ml, and 2.50×10^5 CFU/ml respectively, and the antibacterial effect of Strain 15 against other 7 vibrios were obtained in different degree. Data also showed that Strain 15 at high concentrations （injection challenge 1.84×10^7 CFU/ml, immersion challenge 4.17 ×10^7 CFU/ml） had potential toxicity to shrimp. In order the identify Strain 15, both gas chromatographic analysis of bacterial whole cell fatty acids and 16S rDNA sequencing were employed. The results showed that Strain 15 was a Pseudoalteromonas sp. Results from this study could provide technical support for developing biological agents used for preventing vibriosis in aquatic animals.