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Avian pathogenic E. coli in some regions of China this thesis, the biological characteristics and resistance to change trend, from the molecular level to explore its popular features and mechanisms of resistance to effective prevention and treatment of disease and the new chicken E. coli veterinary drugs developed to provide a reference. Sick, dead chickens in this study is divided into three parts: 1, of chicken pathogenic E. coli isolation, identification and O serotype analysis since the typical symptoms of E. coli disease in China's northeast, Hebei, Shandong, eastern China region poultry farm isolated 33 bacteria. Identified 21 isolates as E. coli by biochemical experiments to prove the 21 E. coli pathogenicity tests on chicks and mice are highly pathogenic E. coli. Glass plate agglutination and tube agglutination method of combining, of 21 chicken pathogenic E. coli O serotypes identified a total of eight E. coli identified as the three serotypes were O 88 (4), O 26 (3 strains), the O 78 (1 strain), accounted for 38.1% of the isolates, 13 stereotypes (two of which occurred self-curing); O 88 serotypes are distributed in the northeast, Shandong, east China, O serotypes 26 are distributed in Hebei, Shandong, east China, so the O 88 and O 26 was the dominant serotype. Avian pathogenic E. coli serotypes numerous and complex distribution, regional differences, the The O serotypes identified to provide a scientific basis for better prevention colibacillosis. Avian pathogenic E. coli resistance monitoring Kirby-Bauer broth coating method recommended by the World Health Organization (WHO) on 21 chicken pathogenic E. coli florfenicol, streptomycin, tetracycline, etc. 12 antibiotics drug sensitivity test results: isolates the highest resistance to amoxicillin, and 100%, the remaining order norfloxacin 95.24%, 95.24% tetracycline, doxycycline 95.24%, ring ciprofloxacin 90.48%, 85.71%, ofloxacin, streptomycin 66.67% florfenicol 57.14%, erythromycin 47.62%, gentamicin, 33.33%, the neomycin 19.05%, and amikacin 19.05 %. 21 chicken pathogenic E. coli have different levels of resistance, and the performance of multi-drug resistant, and a minimum of 4 resistance, 12 resistance, resistance to an average of 8. Different regions separated chicken pathogenic E. coli sensitive drugs: Northeast China isolates sensitive to florfenicol, neomycin, and amikacin; Hebei region isolates sensitive to gentamicin and neomycin; Shandong regional isolates sensitive to neomycin and amikacin; East China isolates were not sensitive to 12 antibiotics. Drug susceptibility testing for clinical basis in scientific medicine. 3, the application of ERIC-PCR method of chicken pathogenic E. coli genotyping of 21 separate chicken pathogenic E. coli genomic DNA was extracted using ERIC-PCR technique, its genomic DNA amplification, the PCR products subjected to agarose gel electrophoresis analysis, drawn according to the Nei similarity coefficient between the various strains in the phylogenetic tree, 21 isolates were divided into A, B, C, D, E, F, G, H, the I, 9 ERIC genotype genotype D, 11: three northeast strain, 3 Hebei strains, 4 northeast beads, an East strains; followed by the E-type, northeast, Shandong, each one; other genotypes strains. Compare different ERIC relationship between genotype and serotype and resistance spectrum same serotype same ERIC genotype different ERIC genotype different serotypes of the same genotype; drug of the same spectrum strains ERIC genotype is basically the same, but also there are different strains of the same individual resistance spectrum ERIC genotype; same genotype strains of the same spectrum of resistance, resistance spectrum differences larger strains.
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