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为鉴定一起齐口裂腹鱼突发传染病的病原,本研究从患病濒死鱼中分离到两株致病菌并对其进行常规理化特性、分子生物学、病理学和致病性试验以及药敏性检测。结果显示,两分离株理化特性与迟钝爱德华菌(E.tarda)特征相符,与GenBank中E.tarda的16S rDNA、gyrB基因、fimA毒力基因和gadB毒力基因的序列同源性均达99%以上,在系统发育树中与E.tarda聚为一族,毒力基因双重PCR扩增出443 bp和584 bp两条特异性片段,综合确认分离株为致病性E.tarda,将其命名为Et-1和Et-2。人工感染鱼出现与自然发病相似症状,并能从发病鱼组织中再分离到相同病原菌。分离菌株对20种抗生素中氟苯尼考、左氧氟沙星等10种药物敏感。
In order to identify the pathogen of a paroxysmal zoospore outbreak, we isolated two pathogens from the moribund fish and conducted routine physicochemical properties, molecular biology, pathology and pathogenicity tests And drug sensitivity test. The results showed that the physical and chemical properties of the two isolates were in accordance with the E. tarda characteristics, and the homologies with the 16S rDNA, gyrB, fimA and gadB virulence genes of E. tarda in GenBank reached 99 % Or more, in the phylogenetic tree with E.tarda poly people, virulence gene double PCR amplification of 443 bp and 584 bp two specific fragments, comprehensive identification of the isolates pathogenic E. tarda, named Et-1 and Et-2. Artificially infected fish appear to have similar symptoms to those found in nature and are capable of isolating the same pathogen from the diseased fish tissue. Isolates of 20 kinds of antibiotics florfenicol, levofloxacin and other 10 kinds of drug-sensitive.