斑点叉尾鮰保科爱德华氏菌的分离鉴定和组织病理观察

Separation of Edwardsiella hoshinae and Histopathological Changes of Channel Catfish, Ictalurns punctatus

对患病斑点叉尾鮰的肝脏病灶进行细菌分离培养,经API20E细菌生化快速试剂条鉴定为保科爱德华氏菌(Edwardsiella hoshinae)。人工感染试验可再现自然条件下鱼病的症状,表现出很强的致病性。病变组织切片观察发现,病变最初是部分肝细胞发生颗粒变性及水样变性,颗粒变性的肝细胞肿大。严重时,细胞周界不清晰,肝细胞内的小空泡连成大空泡,核悬浮在肝细胞的中央,细胞核肿大,并出现部分肝细胞的核浓缩、破裂、溶解消失。保科爱德华氏菌对斑点叉尾鮰具有显著致病性,可引起肝脏发生严重病变。

Pathogenic bacteria strain was isolated from the livers of the diseased channel catfish.It was identified as Edwardsiella hoshinae by biochemical identification.Therefore artificial infection test indicated that the Edwardsiella hoshinae showed strong pathogenicity and caused the same symptoms as the naturally infected fish’s.As histopathological slices indicated,some liver cells showed granule degeneration and swollen,and some showed cellular hydropic degeneration at the beginning.Subsequently the cell membranes were illegible.Small vacuoles of liver cell merged into the bigger.Some cell nucleus suspended in the center,condensed,burst,dissolved and finally disappeared.These results demonstrated that Edwardsiella hoshinae had strong pathogenicity in channel catfish and could lead to pathological changes of liver.