Isolation And Investigation Of Pathogenic E.coli From Hubei Province And Establishment Polymerase Chain Reaction To Detect Pathogenic E.coli

Colibacillosis, caused by avian pathogenic E.coli (APEC) is a major problem for the poultry industry resulting in significant losses annually. However, Prevention and treatment of this disaese can not be easy, because of diverse serotype and increasing antimicrobial resistance. Therefore, it is necessary to isolation and analyze the virulence factors of this pathogen in the Hubei province, to find out the regularity of invasion and to make out scientific possible measure of prevention and cure.E.coli strains were isolated from sick chicken in different poultry industry in Hubei province, and then they were cultured, purified and tested under microscope by common method, and the result of physiology and biochemistry test thirty-nine strains with culturing were morphological characters were isolated. Serotype appreciation of 39 strains were made and classified as 3 serotypes. The main serotypes were 01, 02, 078, which were serotyped occupied 53.8% of total isolates similar with others investigation.Kieby-Bauer paper method was adopted to make susceptibility test to 39 isolated strains with 19 kinds of susceptibility test paper slip. The results of susceptibility tests showed that the medicine resistance of the isolated strains was rather strong, the bacteria only showed high sensitivity to amikacin and spectinomycin, which would be used to instruct the administration procedure.The E. coli strains were investigated for the presence of 11 virulence associated genes described for septicemic (papC, irp2) and APEC ( iucD, tsh,fimH, and hlyE). Five genes were significantly distributed among APEC strains, while most of the other investigated genes could be demonstrated lower. Most of the strains harboring iucD (66.7%) also gave positive results for iss( 71.79%). Genes irp2(68.0%), necessary for Yersinia to acquire iron in the mouse infection model. Moreover, we found papC in 15.4% and astA in 23.1% of the field strains. A significant amount of strains (57.3%) harbored a combination of iucD, iss, cvi/cva and irp2 virulence-associated genes, presumably rendering these strains particularly virulent. These findings provide novel insights into the presence and distribution of virulence-associated genes in avian pathogenic E. coli field strains, which will help to more comprehensively characterize APEC in future epidemiological studies.