青虾“软壳综合症”病原及其特性

Identification and Biological Characteristics of the Pathogen Causing Macrobrachium nipponense Soft-shell Syndrome

摘要:

从患软壳综合症的濒死青虾体内分离到一株细菌QXL0711B, 经人工感染试验, 其对青虾的半数致死浓度(LC50)为1.47×106 CFU/mL, 具有较强毒力。API 32E系统鉴定及16S rRNA序列分析, 该病原菌为维罗纳气单胞菌温和生物变种(Aeromonas veronii biovar sobria, 登录号: FJ808727)。其系统发育分析表明, 菌株QXL0711B与维罗纳气单胞菌(登录号: X71120)和维罗纳气单胞菌温和生物变种(登录号: AY987729)的亲缘关系最近,

Abstract:

A pathogenic bacterial strain QXL0711B was isolated from freshwater shrimp (Macrobrachium nipponense) suffering with soft-shell syndrome. The 50% lethal concentration (LC50) of strain QXL0711B was 1.47×106 CFU/mL, which showed that strain QXL0711B was rather strong virulent to Macrobrachium nipponense. Strain QXL0711B was gram negative and had β-hemolytic activity on sheep blood agar. By means of API 32E identification and 16S rRNA sequence analysis, strain QXL0711B was identified as Aeromonas veronii biovar sobria (locus number: FJ808727), which was the closest relative to Aeromonas veronii strain (locus number: X71120) and Aeromonas veronii biovar sobria strain (locus number: AY987729) with 99% homology. In addition, strain QXL0711B was highly sensitive to ceftriaxone ceftazidime ciprofloxacin enrofloxacin and norfloxacin.