Study On Separation,Identification Of Escherichia Coli And Treatment For Piglet Yellow Dysentery Diseases In Jingzhou District

Piglets yellow dysentery that caused by pathogenic Escherichia coli is an acute and deadly infectious diseases,which usually occurred in the 1-7 d piglets.It is characterized by diarrhea,yellow liquid waste,higher morbidity.Although pathogenic Escherichia coli has been a lot of research,the disease is still one of the endemic diseases that mainly affects swine breeding.The abuse of antibiotics for treating the kind of diseases makes this e.coli has a strong resistance.Therefore,exploiting effective vaccine directing at regional specific e.coli to prevent piglet's yellow dysentery has being a hotspot.In this context,2 experiments were conducted to identify the e.coli and treat the piglet yellow dysentery diseases in Jingzhou district.Experiment 1 was conducted to separate and identify the e.coli serotype,which induces piglet's yellow dysentery,in Jingzhou district,subsequently experiment 2was carried out to make inactivated vaccine and evaluate their immune effect,it is getting very important to provide theoretical knowledge and technical guidance for prevention and treatment of piglet's yellow dysentery in the region.Experiment 1.Separation and identification the e.coli serotype of piglet's yellow dysentery in Jingzhou district127 samples were collected from the guts and fecal from different pig farms in Jingzhou district,and we carried out the experiments of nurturing,staining,biochemical test and so on.As a result,121 strains gained show the typical syndromes in characterization,shape an d staining,including 23 strains of high pathogenicity,58strains of high pathogenicity,31 strains of medial pathogenicity and 9 strains of low pathogenicity,and the separation rate was 92.6%.The results came from serotype identification test shown there were 15 serotypes of the"O"type of e.coli in this district,and O₁₄₉,O₈,O₂₀0 and O₁₀₁01 were overwhelming serotypes of e.coli that induced piglet yellow dysentery in Jingzhou district.Drug sensitive test found there were drug-fast and multiple drug resistance for this e.coli in the region.Here,the Ciprofloxacin and Kanamycin both were with relatively high sensitivity.Experiment 2.Preparation of the inactivated vaccine and the evaluation of immune effect for pigletFirstly,we prepared the inactivated vaccine based on the overwhelming serotypes of e.coli that induced piglet yellow dysentery in Jingzhou district.After proving safe and immune protection in mice and pregnant sow the vaccines were evaluated the immune effect for piglet via a field study.Here,80 healthy pregnancy sows selected from local farm were randomly assigned to the control group?Control,n=20?,Genetic engineering vaccine group?GE-immune,n=30?and Inactivated vaccine group?IV-immune,n=30?,then these sows were immunized using corresponding vaccine.Results showed that the incidence of dysentery piglets were38.18%,25.44%and 12.98%in Control group,GE-immune group and IV-immune group,respectively.One-way ANOVA found GE-immune and IV-immune group both had significant protective effect compared with Control group in term of preventing dysentery piglets?P<0.001?.In addition,the mortality rates of piglets were 59.24%,18.73%and 14.01%in Control group,GE-immune group and IV-immune group,respectively.Chi-square test results shown that when compared with the Control group using the genetic engineering vaccine or inactivated vaccine,which was immunized on the pregnancy sow,could significantly reduce the mortality of the piglets?P<0.001?,while apparent difference of declining mortality failed to find in GE-immune group and IV-immune group?P>0.05?in this study.These results in two experiments showed that 121 strains gained from Jingzhou district exhibited 15 serotypes of the"O"type of e.coli,in which O₁₄₉,O₈,O₂₀0 and O₁₀₁01 were overwhelming serotypes of e.coli that induced piglet yellow dysentery.Furthermore,the inactivated vaccine was prepared based on the overwhelming serotypes of e.coli and injected to pregnancy sows,and the results indicated that the inactivated vaccine could significantly reduce the incidence of dysentery and mortality of the piglets.