The Isolation,Identification And Detetion Of Virulence Of Lung Pathogenic Escherichia Coli Inshannxi Musk Deer

Musk deer is a national protected animal,musk has high medicinal value.Artificial breeding of musk deer began in Chinasince 1958.But due to various factors such as disease and environmental effects of the musk deer breeding scale have been restricted.Especially the musk deer pneumonia morbidity and mortality caused by Escherichia coli bacteria is high,causing great harm to the musk deer breeding.February 2016,some musk deer from Shaanxi Baoji musk deer breeding base sudden onset,necropsy revealed the main lesion in the lung,the biological characteristics,the drug resistance of bacteria,pathogenicity,virulence gene and 16 SrRNA amplification and sequences of these two strains s were investigated.The main results are as follows:1.2 bacteria were isolated from the diseased tissue berezovskii,strain 1 and strain 2.Strain 1 as the surface is smooth,translucent,a diameter of about 3mm gray white colonies,microscopic examination showed Gram-negative bacteria,with rounded ends,paired or scattered;2 strains for the smooth surface,the edge is neat,translucent,a diameter of about 1mm white colonies,a microscopic examination of gram negative bacilli,gathered.2.The fermentation of sugars(glucose,maltose,lactose,L-Arabinose),M.R test,V-P test,indole test,citrate utilization test a total of 5 biochemical tests were experimented.According to the criteria of Berger’s "Bacterial Identification Manual",we can determine the strains for Escherichia coli.3.The 16 S rRNA sequences of the two strains were amplified with a pair of specific primers by PCR.The BLAST analysis result showed that the identity of 16 S rRNA sequences of two strains to that of typical strains of Escherichia coliwere 100%.Strain 1 was 100% similar withE.coli O104:H4,Strain 2 was 100% similar withE.coli O78.Thus,strain 1 and strain 2 can be identified as Escherichia coli.4.We choosed 12 kinds of commonly used antibiotics to measure their drug sensitivity.In this way,cephalosporins have the strongest effect against bacteria among the 12 kinds of antibiotics.Cephalosporins(cefazolin,ceftriaxone)and monocyclic β-lactam(aztreonam)are sensitive to the two pathogenic E.coli;aminoglycosides(streptomycin)was moderately sensitive to them;they were resistant to other categories of antibiotics.5.The pathogenicity test showed that strain 1 and strain 2 had strong toxicity,and the mortality rate was 75% in the experimental group after intraperitoneal injection of 72 h.In the lungs of the dead mice,strain 1 and strain 2 could be isolated.6.The ompA genewere detectedfrom the two strains through the independent gene detection test.the other type of adhesin(afa/draB、iha、sfa/focCD),iron transport system class(sitD ep.a,sitD chr.,iucD.a),serum type(neuC)and toxins(sat,vat)9 kinds of virulence genes were not detected.Therefore,the isolation of two Escherichia coli may be caused by the effect of outer membrane proteins.In summary,in this study,the case is pneumonia caused by Escherichia coli.The isolated Escherichia coli has strong resistance and pathogenicity,andthe pathogenesis may be the function of the outer membrane protein.The result of drug sensitivity test guide the treatment and the isolated strain as antigen,the vaccine is immune and the condition is controlled.