Abstract: Chicken Escherichia coli samples were collected from the patient or dead chickens with typical clinical symptoms in western Liaoning province in the test, chicken Escherichia coli was isolated,cultured and identificated, 89 strains of chicken Escherichia coli were isolated. Identified 82 strains, belonging to 9 serotypes, they were O₁,O₂,O₈,O₁₅,O₁₈,O₃₅,O₇₈,O₁₁₄,O₁₄₁ serotypes respectively, O₃₅ and O₁₈ were predominant serotypes of chicken Escherichia coli in the western of Liaoning province. E.coli that was isolated and purified was cracked by supersonic wave,add to the double-aldehyde sensitization red blood cell, and made up of E.coli O₃₅ IHA diagnostic reagents, the specificity, sensitivity and stability were verified.Kirby-Bauer method was used as drug sensitive test to the 89 strains, and 12 standard drug sensitive slips were selected in the test. The results showed that the indirect hemagglutination diagnostic solution was specificity and sensitivity, and the resistant strains were detected in all region, just Forfenicol, Ceftiofur, Levofloxacin and Sarafloxacin were sensitive to chicken Escherichia coli.

Key words: chicken Escherichia coli; isolation and identification; serotypes; IHA diagnostic solution; drug sensitive test