| In this paper,the effects of Astragalus and Millettia specisoa Champ on the prevention and treatment of multi-drug-resistant E.coli infection in animals were studied.The pig source materials were collected for bacterial isolation and identification,drug sensitivity test,virulence test,detection of virulence genes and drug resistance genes of some strains,and multi-drug resistant Escherichia coli suitable for establishing animal models were screened.The effects of Astragalus and Millettia specisoa Champ water extracts on the growth of multidrug-resistant E.coli were studied by drug sensitivity test and growth curve test.Through the mouse disease model test,the total fatality concentration and the median fatality concentration were found,and the clinical symptoms,organ changes,and blood routine tests of mice were observed to study the protective effects of Astragalus and Millettia specisoa Champ water extracts on animal models.The prevention effects of Astragalus extract and Millettia specisoa Champ extract on animal models of multidrug-resistant E.coli infection were further studied by macro genomics and transcription techniques.The main experimental results are as follows:1、Clinically collected pig-derived materials,65 strains of E.coli were isolated,all of which were multi-drug resistant Escherichia coli,and 49 strains of E.coli were pathogenic,20 of which were lethal,and 7 of which were caused by E.coli.The pathogenesis of mice is long and has obvious pathological features.2、Combined with PCR technology to analyze the resistance genes and virulence genes of some E.coli strains,a multi-drug resistant Escherichia coli suitable for establishing animal disease models was screened,which contained 8drug resistance genes,namely tet B,CTX-m-u and CTX-m-1,rmt A,rmt D,Sul1,Sul2,oqx A,containing 7 virulence genes,namely Iss3,fim C,cva C,sod A,csg A,tsh,mar A.The total lethal dose(TLD)was 7.5×10~7CFU/m L and the median lethal dose(HLD)was 1.9×10~7CFU/m L by intraperitoneal injection.3、The E.coli growth curve was drawn by OD method.It was found that the Astragalus and Millettia specisoa Champ at the concentration of 100 mg/m L and 200 mg/m L would be smaller.At 10 mg/m L and 20 mg/m L,the aqueous extract of Astragalus membranaceus can shorten the logarithmic growth phase and increase the absorbance during stationary phase.Blood routine tests have found that the extract of Astragalus and Millettia specisoa Champ can increase the number of white blood cells and the number of platelets.4、Through the analysis of intestinal microbial diversity in mice,it was found that the extracts of Astragalus and Millettia specisoa Champ had certain effects on the diversity,richness and evenness of intestinal microbes in mice.The richness of norank＿f＿＿Bacteroidales＿S24-7＿group and Lactobacillus belonging to the Bacteroidales group was higher than that of the model group,and the abundances of Bacteroides and Klebsiella were all abundant.Below the model group.5、Using the transcriptome-related technology to study the liver of mice,it was found that both Astragalus and Millettia specisoa Champ can up-regulate the expression of genes important for immune function such as Lbp,Vnn1,and Il33,and also down-regulate the inflammatory response.Certain gene expression can also act on the Toll-like receptor signaling pathway(map04620),the TNF signaling pathway(map04668),and the T cell receptor signaling pathway(map04660),which are important links to immune function.The preventive role of the model. |
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