The Identification Of Bacterial Pathogen Of Trionyx Sinensis And The Clone Of Hermolysin Activatorgene Of Edwardsiella Tarda

Three strains named NO.1, NO.2, NO.3 were isolated from diseased Trionyx sinensis. After they were identified by morphological and biochemical characteristics the result turns out to be that NO.1 is K.peneumoniae. NO.2 is Aeromonashydrophila or Aeromonas sobria. NO.3 is Edwardsiella tarda.The 16S-rDNA genes of three strains are amplifred, cloned ,sequenced and then aligned. The alignment result shows NO.1 is closest to K.peneumoniae, NO.2 is closest to Aeromonashydrophila, NO.3 is closest to Edwardsiella tarda . From the results of morphological ,biochemical characteristics identification and 16SrDNA genes alignment, it is concluded that NO.1 is K.peneumoniae, NO.2 is Aeromonas hydrophila, and NO.3 is Edwardsiella tarda.The pathogenicity of three strains to turbot is studied by posterior limb muscle injection, from which it's clear that NO.3 is highly pathogenic whereas NO.1 and NO.2 have no pathogenicity.There are a lot of differences in the three pathogen which are used in the susceptible test. NO.1 is resistant to Clindamycin Hydrochloride and Ciprofloxacin.NO.2 is resistant to peillin G,TetracyclineTablets and Furazolidone. NO.3 is resistant to peillin G, Vancocin, Ampicillin and Proctaphlin Sodium.The hemolysin activator gene fragment of Edwardsiella tarda is amplified by PCR. The nucleotide sequence shows that the gene is consists of 599 base pairs and the hemolysin active gene nucleotide sequence of NO.3 is 100% similarity with eha which is done by GAO Daqing.In this study, through using the quivkly dentermine of aquatic virulence gene and the study of cloned the eha, a good foundation for controling this Et disease will be founded.