红鳍东方鲀(Takifugu rubrips)病原杀对虾弧菌的主要生物学特性研究

BIOLOGICAL CHARACTERIZATION OF VIBRIO PENAEICIDA SP.NOV.FROM TAKIFUGU RUBRIPS L

采用表观分类学及分子生物学方法,对从发病的养殖红鳍东方鲀中分离的细菌进行了主要生物学特性研究。主要包括形态特征、理化特性等较系统的表观分类学指征鉴定;同时对代表菌株进行了16S rRNA基因的分子鉴定,测定了16S rRNA基因序列、分析了相关细菌相应序列的同源性、构建了系统发生树;结果表明,分离菌为弧菌属(Vibrio Pacini 1954)的杀对虾弧菌(Vibrio penaeicida sp.nov.Ishimaru et al 1995)。代表菌株(HC051105-6株)16S rRNA基因序列长度(不包括引物结合区)为1443bp(GenBank登录号:EU073023),代表菌株(HC051105-8株)16SrRNA基因序列长度(不包括引物结合区)为1450bp(GenBank登录号:EU073024)。择代表菌株做对健康红鳍东方鲀的人工感染试验,认为分离鉴定的杀对虾弧菌在被检红鳍东方鲀病例具有一定的病原学意义。药敏试验结果显示,对供试37种抗菌药物中,在一些药物中存在耐药性的菌株间差异。

High-frequency mortalities occurred in aquiculture pufferfish in Hebei of China in November 2005, and the death rate stayed over 15% for over 5 weeks, and those of moribund lost appetite with erratic swimming. Approximately 30% of the sick fish had haemorrhages on body surface （including fin, base of fin, head, mouth, and abdomen）. Histological examination of the liver and kidney showed spots of necrosis and pervasive bleeding. However, no evidence of parasitic infection by protozoan or metazoan was observed in gills and skin. Biological study was then carried out on possible pathogenic bacteria isolated from infected individuals using traditional and modern molecular techniques in morphology, physiology and biochemistry. Molecular identification of the isolates was conducted, the 16S rRNA genes were partially sequenced and compared with those of databases, and molecular phylogenetic trees were constructed. The isolates were Gram-negative, arranged singly or in pairs, round-ended rods in shape （some slightly curved）, no-endospores, and （0.5-0.8） μm × （1.2-2.5） μm in size. The sequenced 16S rRNA gene of strain HC051105-6 （GenBank accession No.EU073023） is 1443bp in length, the sequenced 16S rRNA gene of strain HC051105-8 （GenBank accession No.EU073024） is 1450bp long, and the two strains shared high similarity （99%-100%） with the 16S rRNA gene of Vibrio penaeicida sp. nov. from GenBank database. The results show that the identified strain belonged to V. penaeicida in terms of morphology, physiology and biochemistry up with the of strain （HC051105-8） was also conducted, revealing pufferfish. regarding criteria. In addition, an artificial infection experiment correspondent pathogenicity of Vibrio penaeicida sp. nov. to pufferfish.