Molecular Epidemiology Of Drug Resistant Genes And Virulence Factors Of Avian Pathgenicity E.coli(APEC) And The Interaction Between Vero Cells And HPI-irp1 Products Expressed By E.coli

1. Isolation and identification of APEC and serotypeMore than 500 bacterial strains were isolated from poultries, which had clinical lesions of colibacillosis with serious fibrin exudation, pericarditis, salpingitis, airsacculitis and yolk peritonitis. After cultured on MaConkey plates, single typical pink colonies were picked out after Gram-dyeing and purified on agar plates. After sugars ferment test, urea enzyme test, IMViC test and growth characteristic on TSI medium, 366 E.coli strains were identified. The serotype of APEC isolates were identified by the tube agglutination test with poly-serum and mono-serum. The serotype of 296 isolates were identified and grouped to 56 serotypes. O78,O88,O24,O109,O93,O9,O11 were main serotypes in this investigation. The results of the serotype test showed that the serotype of APEC became more complicate than ever. Beside the increasing of quantity of type, the serotype of APEC had relation to area of isolation and their hosts. (1)The isolates from different area had difference. The main serotypes of Nantong isolates were O78,O24,O11,O26,O45,O74;The Yancheng isolates were O78,O87;The Yangzhou isolates were O93,O24,O88;The Changzhou isolates were O78,O109;The Xuzhou isolates were O78,O86,O109,O1;The Taizhou isolates were O86,O9. (2) The isolates from different host had evident difference. The serotypes of isolates from chicks, ducks, geese were grouped to 41 serotypes, 21 serotypes and 11 serotypes respectively. The main serotype of isolates from chicken was O78, O109, O88, O24; The main serotype of isolates from duck was O78; The main serotype of isolates from goose was O9,O93,O88,O24. Only three serotypes O11, O86, O107 they all shared.