Sichuan Chicken Serotype Identification Of Pathogenic E. Coli And Plasmid Dna Analysis

43 chicken E.coli strains isolated from 17 avain farms in 10 areas in Sichuan Province were determined to be pathogenic chicken E.coli by biochemical test and pathogenic test. The isolates were studied in three aspects: drug resistance to 16 antibiotics , 0 serotype and fimbriae identification, and plasmid DNA profile. The results showed: (1) All E.coli isolates had multi-resistance. The sensitive drug to the most isolates were Cefa.zolin and Neomycin, and the least sensitive drug to isolates wereTetracycline, Oxytetracycline and Benzylpenicitin Potassium. The results of drug sensitivity tests could ofié‘¢ the scientific reference to select drugs for farms. (2) Among 43 E.coli strains, serotype of 36 strains were determined. 15 kinds of 0 serogroups were discovered. The predominant serotypes are 089 (13.9%)~ 0141 (13.9%)~ 0119 (13.9%)~ 0127 (11.1%) #l 0131 (8.3%) .Theserogroups were distinct in different areas. The fimbriae type of 33 isolates were determined. 30 isolates?fimbriae type are type 1, and 3 isolates?fimbriae were type P. (3) Plasmid were discovered in all E.coli isolates. Plasmid profile analysis indicatesd that the isolates derived from the same source demonstrated the identical or similar profiles and those from different sources exhibited the distinct profiles. The plasmid DNA cleaved with Hind III, EcoR I and BamH I further proved that result. The plasmids Of 23 E.coli isolates are clustered by UVIBand software , and 23 isolates were classified as three types according to the genetically homologous correlationship. There are no direct relationship between the serotype and plasmid profile. Plasmid DNA profile analysis offer the scientific reference to molecular epidemiology investigation of avian colibacillosis.