Studies on Epidemiology of the Chicken Colibacillosis

93 stains of chicken's pathogenic E.coli were isolated from chicken farms of 32 districts and cities in Henan province and studied in three aspects: O serotype identification,drug-resistance to 16 antibiotics,and plasmid DNA pattern.The results show that the predominant serotypes are O78(35.14 %),O1(18.92%),O2(13.51%) and all isolates are multi-resistance.The antibiotic resistance species vary from 3 to 14.Among the drug-resistance pattern of the 93 strains,58 kinds of pattern could be determined,and the 93 stain E.coli can divide into 49 kind's plasmid pattern.The numbers of the plasmid bands are from 1 to 6.