长江江豚饵料鱼源温和气单胞菌的鉴定及毒力分析

Isolation and identification of Aeromonas sobria from the diseased prey fish of the Yangtze finless porpoise

湖北长江天鹅洲白鱀豚国家级自然保护区内长江江豚(Neophocaena asiaeorientalis asiaeorientalis)的多种饵料鱼暴发细菌性疾病,主要表现为烂鳍、白尾等临床症状,严重威胁长江江豚的食物和水生环境安全。自患病的■条(Hemiculter leucisculus)等饵料鱼的肝、脾和肾中分离出多株菌株,其中分离株SS161012经16S rDNA、gyr B基因序列测定,形态观察及生理生化分析等方法鉴定为温和气单胞菌(Aeromonassobria)。该菌编码溶血素(Hly)、外膜蛋白(Omp)、粘附素(Aha)、丝氨酸蛋白酶(Ahp)等毒力基因。致病性试验显示,分离株SS161012可通过注射感染和划痕浸泡感染致试验鱼死亡,且创伤浸泡感染死亡率明显高于注射感染。药物敏感性测试显示该菌株对环丙沙星、左氧氟沙星等BD Phoenix^TM分析鉴定系统基本药物和氟苯尼考、恩诺沙星等水产常用药物敏感。

A severe disease of prey fish of the Yangtze finless porpoise was occurred and caused mass mortality in the Tian-e-zhou National Reserve for Lipotes vexillifer in Shishou,Hubei Province.Several bacterial strains were isolated from the diseased prey fish\ Among them,SS161012 was identified as Aeromonas sobria through 16S rDNA,gyrB gene sequence determination,morphological observation,physiological and biochemical analysis (PhoenixTM,BD).Virulence gene amplification showed that SS161012 harbors several virulence genes,including hemolysin (Hly),outer membrane protein (Omp),adhesin (Aha) and serine protease (Ahp).Artificial infection with intraperitoneal injection and immersion infection indicated that SS161012 was virulent to gibel carp (Carassius gibelio ) indicating SS161012 is a moderately virulent strain.Antibiotic sensitivity tests demonstrated that SS161012 was sensitive to most of the chosen antibiotic including florfenicol,enrofloxacin.