| Goose colibacillosis is an acute infectious disease caused by Escherichia coli,Acute infectious disease caused by E.coli,usually called "egg yolk plague" often occur in goslings less than 2 weeks old and are septicemia.Adult geese cause egg yolk peritonitis,which significantly reduces the laying rate of female geese.This disease is highly infectious.In recent years,due to the abuse of antibiotics,the incidence of geese has increased year by year,which has brought huge economic losses to the goose industry.There are many serotypes and genotypes of coli in geese.Different strains carry different types and quantities of virulence genes,such as adhesion,iron uptake system,virulence island,hemolysin and drug resistance genes.These factors are as follows: It is difficult to prevent and cure the disease.In order to determine the epidemic situation of goose colibacillosis in this area,the pathogen isolation and identification,virulence gene detection,drug resistance detection and genotyping on goose colibacillosis in some areas of Heilongjiang were carried out in this study.To lay the foundation for control.Isolation and identification of E.coli from goose: collect intestinal and liver disease materials from goose farms in the surrounding areas of Daqing,Heilongjiang(Daqing,Anda,Qiqihar,Heihe,Nehe,Suihua,Qinggang,Taikang)for bacterial isolation and biochemistry Test and 16 S r RNA and other identification.Results 148 strains of E.coli were isolated and identified from 178 affected geese,with a detection rate of 83%.Detection of virulence genes of E.coli from geese: Virulence genes of 148 strains of E.coli were detected by polymerase chain reaction.The virulence gene-bearing strains were tested in mice to observe their pathogenicity,and pathological autopsies and regression tests were carried out in sick and dead mice.The virulence gene-bearing strains were tested in mice to observe their pathogenicity,and pathological autopsies and regression tests were carried out in sick and dead mice.The major virulence genes were iuc D,Pap A,Omp A and Tsh.The detection rates were 91%,90%,89% and 86% respectively.No Ler,ibe A and iro N were detected.The pathogenicity test of the strains with virulence factors was carried out in mice,and it was confirmed that 80 strainscaused the death of mice,and they were highly pathogenic strains.The pathogenicity test of the strains with virulence factors was carried out in mice,and it was confirmed that 80 strainscaused the death of mice,and they were highly pathogenic strains.Detection of K-B resistance of pathogenic strains by disk method.The results showed that the drug resistance of E.coli isolated from geese was serious,with 85%multi-drug resistant strains,which were sensitive to gentamicin and levofloxacin.Accounting for 57% and 71.5%,respectively.Tetracycline,ampicillin,trimethoprim and ciprofloxacin hadthe highest drug resistance rates,which were 100%,85%,86% and 83%respectively.Multi-sequence locus typing: multiple housekeeping genes(din B,put P,pol B,trp B,pab B,icd A,uid A、Trp A)are amplified by PCR,and the pathogenic strains are identified by multi-sequence locus typing(MLST).The results showed that the pathogenic strains of E.coli from goose were divided into 54 ST types,showing diversity.ST131,ST208 and ST178 are the most popular types of ST in this area,with the detection rates of 15%,14%and 5% respectively.In summary,the isolation rate of goose-derived E.coli is relatively high in Daqing,Heilongjiang province.Most strains carry toxic genes,which is pathogenic.The isolates are more resistant to commonly used antibiotics,and multi-sequence locus typing appears.Diversity.This study provides a theoretical reference for the prevention and treatment of goose colibacillosis in this area. |
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