蛭弧菌Bdh5221株理化特性和16S rDNA序列分析

THE PHYSIOLOGICAL CHARACTERISTICS AND 16S rDNA SEQUENCE ANALYSIS OF BDELLOVIBRIO SP. Bdh5221

蛭弧菌海水菌株Bdh5221于2005年8月从海南琼海对虾养殖场周边排水沟水样中分离所得,具有裂解多数革兰氏阴细菌的特性。在前期Bdh5221噬菌谱研究的基础上,利用其可利用热致死革兰氏阴细菌的生长特性,对其理化特性、药敏特性和16S rDNA序列分析进行了相关研究。结果表明:该株蛭弧菌为革兰氏阴性菌,呈杆状、弧状,一端有极长的极生鞭毛,细菌大小在(0.2—0.5)μm×(0.6—1.5)μm左右;生化实验表明:Bdh5221明胶穿刺试验和接触酶试验呈阳性,氧化酶反应呈阴性,对弧菌抑制剂O/129敏感;药敏实验表明:此菌对新霉素、卡那霉素、恩诺沙星敏感,对青霉素、磺胺嘧啶和万古霉素不敏感;对其16S rDNA序列的测定、分析表明,与其同源性最高的细菌是一株新发现的海洋新种细菌Kordiim onas gwangyangensis,同源性高达99%,而与其他蛭弧菌属细菌的同源性从90%到70%不等,并针对其基因序列做了相关进化分析。

A bacterium which isolated from prawn nursery wastewater in Qionghai, Hainan Province in August 2005, was maintained by our laboratory and named Bdh5221. According to previous study, Bdh5221 could prey most Gram-negative bacterium and can also be cultivated by using heat-killed Gram-negative bacterium. In the present study, morphological, physiological characteristics, drug sensitivity, and 16S rDNA sequence of Bdh5221 were analyzed. The morphological studies showed that the strain Bdh5221 were Gram-negative, motile and had a bacilliform or bacilliform shape with flagellum at one side, which size was mostly （0.2-0.5） μm × （0.6-1.5） μm. The physiological characteristics showed that this bacterium were eatalase-positive, oxidase-negative, gelatin colliquation-positive and sensitive to the vibriostratic agent O/129. Drug sensitive results indicated that this bacterium were enrofloxacin-positive, neomgcin-positive, biograncetin-positive, penicillin-negative, Sulfadiazine-negative and vancocin-negative. 16S rDNA gene of Bdellovibrio sp. Bdh5221 was 99% similar with a navel marine bacterium Kordiimonas gwangyartgensis. The similarity with all recognized Bdellovibrio-and-like organisms was from 90% to 70%. It indicated that the bacterium might be a novel Bdellovibrio-and- like organisms.