Isolation And Identification Of Chicken Pathogenic Escherichia Coli And Development Of Inactivated Vaccine In Jilin City

In recent years, chicken E.coli disease prevailed many times and caused great economic losses in Jilin City. Pathogenic materials were collected from 10 chicken farms in 5 areas, through isolation and culture of bacteria, biochemical test, animal test and serological test, eighteen strains pathogenic E.coli were isolated and identified. And their serotypes were determined, being O₁,O₂,O₅,O₉,O₂₀,O₂₄,O₇₃,O₇₈ respectively. Among them, O₇₈,O₂,O₉,O₂₄ occupied 77.8% in determined strains and were the dominant serotypes. At the same time, their immunities were detected.E.coli strains of the four dominant serotypes, O₇₈,O₂,O₉ and O₂₄, were chosen for preparing the candidate inactivated vaccines. Through seeds preparation, purity test, live bacterial count, inactivation and inactivation test, ndotoxin detection, oil-emulsion preparation, aqueous phase preparation and vaccine emulsification, the local multivalent oil emulsion inactivated vaccine were developed.Though the physical characteristics test, sterility test, security test, effect test, immunity initiation test, immune duration test, immune retention test, minimum immune dose test and field immunity test, the vaccine was proved to have high security and well stability. The duration of immunity was as long as 6 months. It met the quality standards of biological product. The minimum immune dose was confirmed to be 0.25ml per chick, 0.5ml per adult chicken it was suitable to be used in Jilin City.