青虾'软壳综合症'病原及其特性

摘要

A pathogenic bacterial strain QXL0711B was isolated from freshwater shrimp (Macro-brachium nipponense) suffering with soft-shell syndrome. The 50% lethal concentration (LC50) of strain QXL0711B was 1.47×l0~6 CFU/mL, which showed that strain QXL0711B was rather strong virulent to Macrobrachium nipponense. Strain QXL0711B was gram negative and had p-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.%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(LC_(50))为1.47×10~6 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,其同源性都为99%.药敏实验结果表明:菌必治、复达欣、环丙沙星、恩诺沙星、氟哌酸等5种化学疗剂对该病原菌有较强的抑菌作用.