Abstract: The bacteria strain FY-024 was isolated from northern sheatfish Silurus soldatovi suffering from fulminant septicaemia and identified by conventional tests of bacterial culture,and by physiological and biochemical characteristics.The results showed that the strain FY-024 was very likely to be Edwardsiella ictaluri.16S rRNA gene of the strain was amplified,and sequenced to investigate the phylogenetic position.A fragment of 16S rRNA gene consisting of 1 417 bp was obtained,sequenced and submitted to Genbank(Accession No.:GQ924477).Compared with that of other related bacterial species,molecular phylogenetic dendrogram was constructed according to the genetic distance.This strain was found to be shared 99.6%-99.9%of homoeology with Edwardsiella ictaluri and clustered into one clade in phylogenetic dendrogram,confirming that this strain being Edwardsiella ictaluri.In addition,the drug sensitivity showed that this strain had high sensitivity to Ciprofloxacin and Enrofloxacin,and the strain FY-024 had a LD50(50%lethal dose,LD50)of 1.08×106cfu per fish calculated by the method of Reed and Muench in the injection challenge test.
2011, Vol. 26 
