Isolation And Identification Of Procine Extracorporeal Pathogenic Escherichia Coli And Pathogenicity Evaluation

Extraintestinal Pathogenic Escherichia coli(ExPEC)is a type of pathogenic bacteria that mainly causes infection of extraintestinal tissues in pigs;it causes symptoms such as nephritis,pneumonia,sepsis and meningitis in procine;ExPEC is susceptible to secondary infections or mixed infections with other diseases,causing certain economic losses to the aquaculture industry.Animal-derived extracorporeal pathogenic E.coli has the characteristics of human communal disease and poses a certain threat to human health.The experiment was conducted based on the harm caused by pig-derived ExPEC.The specific research content and results are as follows:1.The infected pigs around Hefei were isolated and identified by the aseptic manipulation of the sick pig's parenteral tissue(heart,liver,spleen,lung and kidney).At the same time,histopathological tests were carried out to obtain 30 porcine sources ExPEC.The pathological section showed that the liver cells of the sick procine liver were denatured,the hepatic cord arrangement disorder and the lung branches were disordered.There were a large number of inflammatory cell infiltration in the tracheal tube,including lymphocytes and neutrophils;2.Then the phylogenetic group test and virulence gene detection were carried out on the isolated ExPEC strains.A group: 6 strains,B1 group: 14 strains,B2 group:4 strains,D group: 6 strains,the detection rate of virulence genes were vaT(70%),hlyD(20%),iutA(33.33%),kpsMII(23.33%),fyuA(16.67%),ireA(3.33%)and afa(3.33%),respectively.In which the amplification rate of vaT and iutA was the highest;3.The pathogenicity test of the strains containing 3 or more virulence genes screened in this experiment was conducted.Observe mouse status and death;Through histopathology found:Infected mouse infected with infection tube,renal tubular epithelial cells swollen,the official cavity was blocked,there is a slight degeneration,etc.alveolar septum widening,there are more lymphocytes;liver:there are large inflammatory areas,mainly neutrophils,There was blood stasis and congestion;Heart: The gap between the machines was enlarged and there was slight edema;4.The antibiotic susceptibility test was performed on 30 strains of porcine ExPEC strains screened in this experiment.The test results showed that all the strains were sensitive to PB;most strains were resistant to cefepime,fosfomycin,minocycline and spectinomycin are more sensitive,the drug resistance rates are: 10%,10%,16.67%,30%;but for ampicillin,lincomycin,bacitracin and rifampicin The resistance rate was 100%.All the strains showed resistance of 10 or more,up to 19,and bacitracin + amoxicillin + trimethoprim + vancomycin + doxycycline + kanamycin + ampicillin + lincomycin + florfenicol + rifampicin + compound sulfamethoxazole accounted for 16.7.%.This experiment mainly through the clinical isolation of the procine source ExPEC,to further understand the epidemiological patterns of this group of bacteria,to provide scientific basis for the guidance of the diagnosis and prevention of procine ExPEC.