Abstract: The liver,spleen and kidney tissue of suspected Aeromonas hydrophila were isolated and identified by common nutrient agar,tryptic soy agar medium and biochemical reagent,three bacteria were aquired,then the genes sequence of three bacteria were tested by 16S rRNA common primer and compared with BLAST, regression test was used to determine pathogenicity of identified Aeromonas hydrophila. At the same time, the common antibiotics azithromycin,amikacin,streptomycin etc.ten kinds was used for drug sensitive test.The results showed that three bacteria i.e. Aeromonas hydrophila,Stenotrophomonas maltophilia,corruption watts bacteria were identified by separate culture,biochemical identify and 16S rRNA common primer,regression test confirmed Aeromonas hydrophila pathogenicity.The drug sensitive test showed that the bacteriostat diameter of azithromycin was 105 and 95 mm respectively for corruption watts bacteria and Stenotrophomonas maltophilia,the amikacin bacteriostat diameter was 105, 95 and 93 mm respectively for three bacteria. The grass carp tissue of suspecting Aeromonas hydrophila was isolated and identified three bacteria,identified Aeromonas hydrophila was proved its pathogenicity,amikacin was the most sensitive for the three bacteria,Stenotrophomonas maltophilia and corruption watts bacteria was sensitive for azithromycin.

Key words: grass carp; Aeromonas hydrophila; separation and identify; drug sensitive test