养殖大菱鲆感染迟缓爱德华氏菌的分离、毒力基因及ERIC-PCR分析

为了调查辽宁省葫芦岛市养殖患病大菱鲆Scophthalmus maximus病原菌感染情况,选用迟缓爱德华氏菌Edwardsiella tarda特异性引物对分离菌株进行PCR鉴定,共分离得到22株迟缓爱德华氏菌。结果表明:迟缓爱德华氏菌毒力基因的PCR扩增显示,22株菌均含有kat B、fim A、gad B、esa V等基因;人工感染试验表明,22株迟缓爱德华氏菌感染并致大菱鲆累积死亡率均为100%;ERIC-PCR结果显示,迟缓爱德华氏菌模式菌株(ATCC15947)与分离株可分为2个基因型,分别标记为Ⅰ和Ⅱ型,其中22株迟缓爱德华氏菌分离株均为Ⅱ型,与ATCC15947菌株为Ⅰ型明显不同。本研究结果为养殖大菱鲆迟缓爱德华氏菌感染的防控提供了依据。

Isolation,virulence analysis and ERIC-PCR genotyping of Edwardsiella tarda isolates from farmed Turbot Scophthalmus maximus(L.)

Pathogen Edwardsiella tarda was isolated from diseased farmed turbot Scophthalmus maximus(L.), i-dentified by PCR with a specific primer and further genotyping by ERIC-PCR analysis to explore the pathogenic bacteria infection of diseased farmed turbot. The PCR amplification of virulence gene of the pathogen E.tarda re-vealed that all the 22 isolates contained the four tested virulence genes(katB, fimA, gadB and esaV). Challenge tests showed that the cumulative mortality of 100% was observed in the turbot challenged with the 22 strains of pathogen. In addition,ERIC-PCR showed that the standard E.tarda(ATCC15947) and all 22 isolates were divided into two genotypes including E.tardaⅠand E.tardaⅡ. The reference strains belonged to E.tardaⅠ,and the iso-lates belonged to E.tarda Ⅱ. The findings will provide very important references for disease prevention in turbot.