Dissertation > Agricultural Sciences > Livestock, animal medicine,hunting,silkworm,bee > Animal Medicine ( Veterinary Medicine) > Livestock, poultry, wildlife diseases > Livestock > Pig

Resistance Analysis and Genotype Research of Pathogenic Escherichia coli Deirved from Swines in Harbin

Author WangLeiJie
Tutor ZhangXiuYing
School Northeast Agricultural University
Course Basic Veterinary Science
Keywords pathogenic Escherichia coli multi-drug resistance plasmid profile PFGE
CLC S858.28
Type Master's thesis
Year 2013
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Escherichia coli disease is one of the most popular diseases in the veterinary clinic. The mainhazards include of yellow and white scour of piglets and Swine edema, causing huge losses in theswine industry. With the antibiotics widespread and uncontrolled overuse in animal husbandry, theproblems of drug resistance, especially multi-drug resistance in pathogenic bacteria has beenexpanded seriously.Compared with developed countries, the resistant forms of Escherichia coli are more severein our country, surrounding the Escherichia coli resistance a lot of research has been done, butmost stay on the detection of drug resistance and resistance genes, the analysis ofmulti-drug-resistant Escherichia coli plasmid and the genetic correlation of multi-drug-resistantEscherichia coli in different regions lack of in-depth and comprehensive understanding. Harbinswine source of multi-drug resistant pathogenic Escherichia coli epidemic hazards. There have notrelevant reports about the prevalence, hazard and the genetic correlation of multi-drug-resistantpathogenic Escherichia coli in Harbin.Using the disk diffusion method of CLSI (2007), antimicrobial susceptibility testing of14antimicrobial agents was performed on a total of48pathogenic Escherichia coli strains isolatedfrom swine farms. The results of the study showed that all isolate presented a multiple antibioticresistance, the resistance rate of pathogenic Escherichia coli isolates to Sulfamethoxazole,Florfenicol was above89%, the resistance rate to Streptomycin, Doxycycline, Chloramphenicol,Enrofloxacin, Gentamicin, Amoxicillin-clavulanate exceeded50%, and Escherichia coli wasrelatively sensitive to Amikacin, Fosfomycin, Polymyxin B, the resistance rate to Fosfomycin,Polymyxin B was2.1%and0, Respectively.Analysis of the plasmid DNA of48strains of E. coli, the plasmid was extracted by thealkaline lysis method of a small amount, and then the plasmid was subjected to agarose gelelectrophoresis analysis and the plasmid with Hind Ⅲ restriction endonuclease digestionanalysis.The results show that: the acquisition rate plasmid was100%, the Escherichia coli isolatesderived from same place have the same or similar plasmid profile, having a certain geneticcorrelation. The strains isolated from different place have different plasmid profile and belong todifferent clones.Genotyping studies of48multidrug resistance pathogenic porcine Escherichia coli were used pulsed-field gel electrophoresis (PFGE), and the results of the resistance phenotype are comparedwith plasmid map results. The results showed that:48Escherichia coli can be divided into18PFGE types, most of the types can be divided into different subtypes. The strains which havedifferent phenotypes and plasmid profiles may owned identical PFGE patterns. Through the resultsof plasmid profiles and PFGE analysis we can found:the Escherichia coli strains isolated from thesame farm in Harbin may exist multiple drug resistance clones transmission. The results alsoshowed that resistance phenotype, plasmid profiles, pulsed-field gel electrophoresis patterns arenot entirely correspondence.

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