罗氏沼虾气单胞菌MrM0602株的分离和致病性研究

Isolation and Pathogenicity of Aeromonas MrM0602 from Giant Freshwater Prawn Macrobrachium rosenbergii

从濒死的罗氏沼虾体内分离到菌株M rM0602,经形态学观察及API 20E鉴定系统鉴定为嗜水气单胞菌。人工感染健康罗氏沼虾,100%致死剂量为1.0×104cfu/m l,半致死剂量(LD50)为3.16×103cfu/m l。测定菌株M rM0602的胞外产物对小鼠和新西兰大白兔红细胞的溶血活性,表明胞外产物对小鼠红细胞有微弱的溶血活性,对新西兰兔红细胞无溶血活性。胞外蛋白酶活力测定显示,菌株M rM0602胞外产物具有很高的蛋白酶活力,且耐热性很强,65℃仍保持较高活性。常规药物敏感性试验表明,菌株M rM0602对环丙沙星和恩诺沙星高度敏感。

Bacterium strain MrM0602 was isolated from the moribund giant freshwater prawn, Macrobrachium rosenbergii cultivated in Gaoyou county of Jiangsu Province. MrM0602 showed high pathogenetic to healthy prawns with LD50 of 3.16 × 10^3 cfu/ml by muscle injection, and was identified as Aeromonas hydrophila by morphological and physiological-biochemical characteristics of Api 20E system. Extracellular products of MrM0602 showed weak hemolyticity to erythrocytes of mouse and rabbit, and had high protease activity when azocasein was used as substrate. MrM0602 was significantly sensitive to ciprofloxacin and enrofloxacin.