Isolation And Biological Characteristics Of The Pathogenic E. Coli Of Chicken In The North Part Of Henan Province

Colibacillosis is an important disease, which harms poultry industry acutely. By statistics,cases of colibacillosis (including complication) are 17.53% of those of total chickendiseases. Prevention and cure to the pathogen can not be easy, because of diverse serotypeand increasing drug resistance. Therefore, it is necessary to invest and analyze the invasionof this kind of pathogen in the north of He Nan province, to find out the regularity ofinvasion and to make out scientific possible measure of prevention and cure.E. coli strains were isolated from sick chicken in 139 poultry yards in the north of HeNan province, and then they were cultured, purified and tested under microscope bycommon method. 147 strains with culturing were morphological characters were isolatedand the isolating rate was 78.62%. The result of physiology and biochemistry test alsoshowed characters of the pathogen. Serotype appreciation of 111 strains were made andclassified as 18 serotypes. The main serotypes were as follows: O₁₄₁, O₁₄₁, O₁₄₇, O₁₄₉,O₈₈, O₇₈, O₁, O₂, O₁₁₅.20 strains of O₁₄₁ occupies 18.02% of the appraised strains; both12 strains of O₈₈, O₇₈, occupied 10.81%; 8 strains of O₁₄₇, O₁₄₉, O₁, occupied 7.27%; 7strainsof O₂ and 6 strains of O₁₁₅ occupied 6.31% and 5.41% respectively. Moreover, there arespecial serotypes such as O₇₆, O₃₅, O₁₀₁, O₁₁₁, O₉₇, O₈₆, O₁₂₅, O₁₃₈, O₁₃₉,O₁₆₁. 88 isolated strains were used to challenge young chicken. Both clinical symptome andpathological changes of dissection fitted typical characters of the pathogen. The strains ofhigh pathogenicity occupied 50%, the middle ones did 26.14% and the low ones did23.86%.Kirby-Bauer paper method was adopted to make susceptibility test to 147 isolated strainswith 33 kinds of susceptibility test paper slip. The results of susceptibility tests showed thatthe medicine resistance of the isolated stains was rather strong, the bacteria only showedhigh sensitivity to Florfenicol, Mequindox Powder, Fubennikaokerongxingfen, CeftriaxoneSodium, Neomycin Sulfate Soluble Powder, Amoxicillin Soluble Powder, Kanamycin,etc.. In this study, self-made extinguishable vaccine of E.coli selected from the experimentalfarm was producted, with other protective method to protect sensitive chicken block,resulting a significant decreasing sickness rate. The ideal effects were also made in infectedflocks using the vaccine with sensitivity medicine and Chinese herb medicine "Junlingsan".Microecological praeparatum used to both laying hens and breeding birds resulted a bettercurative effect, and disease incidence could only reach 2.58%. So, laying rate raised for 3%-7%. Moreover, the synthesized methods of prevention and cure should be improved toprevent the pathogen, such as management of feeding and degermation.