Isolation and Identification of Chicken Pathogenic Escherihia Coli in HeBei Province

91strains of Escherihia coli are isolated from chicken fram in different districts in HeBei province and identicated as pathogenic Escherichia coli, The results of serotyping shows that there are 13 serotype in the pathogenic Escherichia coli altogether except that 23 strains could not be serotyped. Among the serogoups,O78,O2,O111,O36have high pathogenicity to chicken, the mean isolation percentage in chicken are 33. 80%,25. 6%, 11. 80% , 5. 88%,5. 88%. O78, O2, O111, are prodominant in serotype, they are 72.10%in the serogtyped Escherichia coli.