| In recent years,Classical swine fever(CSF),Porcine reproductive and respiratory syndrome(PRRS,also known as swine blue-ear diseases)and Porcine pseudorabies(PR)have been the main diseases that endanger the production of pigs,causing serious economic losses in China's pig industry.Due to the unreasonable use and abuse of antibiotics,Escherichia coli,one of the common bacteria in animals and the environment,is very susceptible to drug resistance,and drug resistance-genes exist for a long time and are easy to spread horizontally among animals,environment and people bacteria,affecting the environment and public health safety.In order to investigate the antibody levels of three swine diseases after immunization and drug resistance genes and drug resistance of E.coli in manure and soil in pig farms in Zhanjiang Area.The immune antibody levels of CSF,PRRS and PR were detected by ELISA in 226 serum samples collected from 13 pig farms of different scales in Zhanjiang Area from 2018-2020.It was used PCR technology to detect 21 common resistance genes in 100 pig manure and soil samples collected from 10 pig farms in Zhanjiang Area,and 88 microorganisms were isolated and identified for their resistance to 22 antibiotics by microbial method.It was discussed preliminarily adout the propagation mode of E.coli fex B resistance genes in manure and soil E.coli by combining transfer and electro-transformation methods.The main results are as follows:1.Antibody detection and analysis of three swine diseases in pig farm in Zhanjiang Area.In order to understand the immune status of CSF,PRRS and PR in Zhanjiang Area,226 serum samples from 13 pig farms were detect by ELISA.The results showed that the average positive detection rate of serum antibodies of the three kinds of swine disease,the PRV-g B was the highest,93.52%;the PRV-g E was the lowest,38.50%;the average positive detection rates of CSF and PRRS serum antibodies were83.74% and 85.71%,respectively.The positive rate of CSF and PRV-g B antibodies in farms with less than 200 pigs was up to 100%,and the positive rate of PRV-g E antibody was the lowest,which was 20%.The positive rates of PRRS and PRV-g B antibodies in farms with more than 200 pigs were both above 85%,and the positive rate of CSF antibodies was above 80%.The level and protection rate of CSF,PRRS and PRV-g B were higher in the pig farms in Zhanjiang Area,but the infection rate of Pseudorabies was also higher.It indicates that the immune effect of CSF,PRRS and PR is good,and the detection and monitoring of the antibody against wild poison of Pseudorabies should be strengthened.2.Determination of drug resistance of Escherichia coli isolated from pig manure and soil.In order to understand the drug resistance of E.coli in pig farm manure and soil,88 strains of Escherichia coli were isolated and identified from 100 manure and soil samples collected from 10 pig farms in Zhanjiang Area.and the drug sensitivity test was conducted to determine the 22 antibiotics Sensitivity.The results showed that the drug resistance rate of isolated Escherichia coli.was higher,Amoxicillin,Doxycycline,Oxytetracycline and Colistin were the highest,all reaching 100%.The drug resistance rate of Cephalosporins were the lowest,all Less than 10%.The resistance rate of most isolated bacteria in the manure was higher than that of isolated bacteria in the soil,and the Multi-drug resistance was mostly 15-22 resistant.This shows that the bacterial resistance in pig farm manure and soil in Zhanjiang Area is serious and the trend of Multi-drug resistance is prevalent.3.Detection and spread of drug resistance genes in pig farm environmentIn order to understand the distribution of drug resistance in pig manure and soil,PCR was used to detect 21 common drug resistance genes in 100 pig manure and soil samples collected from 10 pig farms in Zhanjiang Area,and explore the spread mode of E.coli fex B resistance gene by combining transfer and electro-transformation.The results showed that 8 antibiotic resistance genes were detected in manure and soil,and the detection rate of each resistance gene was higher than 50%;The detection rate of most drug resistance genes in manure was higher than that in soil;Drug resistance genes were similar in manure and soil,where E.coli with fex B gene combined and transferred to form 4 zygoses and 1 strain was successfully transformed by electricity.It shows that there are many kinds of drug resistance genes in the manure and soil environment in Zhanjiang Area,which can cause environmental pollution throughhorizontal transmission in the manure and soil bacteria,and pose a certain threat to public health safety. |
PDF Full Text Request