欧洲鳗迟钝爱德华氏菌的分离鉴定

Isolation and identification of Edwardsiella tarda in Anguilla anguilla

目的对欧洲鳗(Anguilla anguilla)迟钝爱德华氏菌(Edwardsiella tarda)菌株ET81126进行分离鉴定。方法采用形态特征观察、人工感染试验、API 20E细菌鉴定系统、16SrDNA测序以及属特异性PCR技术对菌株ET81126进行分析。结果人工感染试验表明菌株ET81126为致病菌,对欧洲鳗的半数致死量为4.55×104cfu/g。按形态特征和API 20E细菌鉴定系统初步鉴定菌株ET81126为爱德华氏菌。通过16SrDNA测序,在GenBank上经同源性序列比对与迟钝爱德华氏菌(登录号EF467289)自然聚为一类,同源率达99%。属特异性PCR扩增图谱显示迟钝爱德华氏菌非典型菌株特有的230bp条带。结论综合生化指标和分子生物学鉴定结果,可确定菌株ET81126为欧洲鳗迟钝爱德华氏菌。

Bacterial strain ET 81126 isolated from liver of the diseased Anguilla anguilla was identified as Edwardsiella tarda by morphological observation,artificial infection experiment,API 20E biochemical characteristics,16SrDNA gene sequence analysis and species-specific PCR technology.The result showed that strain ET81126 was proved to be a pathogen by artificial infection experiment,and the LD50 to A.anguilla was calculated as 4.55×104 cfu/g.Strain ET81126 was similar to Edwardsiella according to morphological observation and API 20E biochemical characteristics.The 16SrDNA gene was sequenced and compared with other bacteria in GenBank.Homology analysis and phylogenetic study showed that it had the highest similarity to Edwardsiella tarda（EF467289）of 99%.The 230bp band of Edwardsiella tarda Atypical was detected in the species-specific PCR finger print.Based on the results obtained,the strain ET81126 was identified as Edwardsiella tarda.