养殖杂交鳢迟缓爱德华菌的分离鉴定

Isolation of Edwardsiella tarda from cultured hybrid snakehead (Channa maculata♀×C.argus♂) and its identification

摘要: 从患病杂交鳢斑鳢(Channa maculata)♀×乌鳢(C.argus)♂体内分离到2株致病菌(ZS201364-1和ZS201364-2)，通过对其生化特性与16S rRNA基因序列进行分析，确定为迟缓爱德华菌(Edwardsiella tarda)。该致病菌兼性厌氧，为革兰氏阴性短杆菌，能运动，能发酵葡萄糖、麦芽糖。吲哚试验和MR试验均为阳性。2株致病菌对杂交鳢的半致死剂量(LD₅₀)分别为7.1×10⁵ cfu · g^-1和5.6×10⁵ cfu · g^-1。ZS201364-1最适生长温度为25~35 ℃、pH为7~8、氯化钠(NaCl)质量分数为1%，对头孢噻肟、环丙沙星、诺氟沙星等抗生素高度敏感。

Abstract: Two pathogenic bacteria (ZS201364-1, ZS201364-2) isolated from diseased hybrid snakeheads (Channa maculata♀×C. argus♂) were identified to be Edwardsiella tarda by analyses of biochemical features and 16S rDNA sequence. The anaerobic, gram negative, bacilliform and motile isolates utilized glucoses and maltose as energy. Both indole and M.R. tests proved positive. The LD₅₀s of the isolates to healthy hybrid snakeheads were 7.1×10⁵ cfu · g^-1 and 5.6×10⁵ cfu · g^-1, respectively. The optimal growth conditions of strain ZS201364-1, which was highly susceptible to cefotaxime, ciprofloxacin and norfloxacin, were 25~35 ℃ pH 7~8 and 1% NaCl.