Analysis Of Typing And Drug Resistance Of Escherichia Coli In Pigs In Some Areas In Guangxi

Escherichia coli is one of the main pathogens causing diarrhea in pigs,causing huge economic losses to the pig industry.And studies have shown that pig colibacillosis has a certain local prevalence.In order to understand the drug resistance,virulence genes and genetic evolution characteristics of pig Escherichia coli in some areas of Guangxi,the following experiments were carried out:1.Collecting fecal swabs or dead pig intestine contents from diarrhea pigs from large-scale pig farms in Nanning,Guilin,Laibin,Liuzhou,Yulin,etc.A total of 116 strains of E.coli were isolated and identified by inoculation with MacKakkai and Eosin Blue,Gram staining,microscopy and PCR.Detection of resistance to common clinical drugs by E.coli isolates from various farms by drug sensitive paper method.The results showed that the isolates showed a certain degree of resistance to 18 drugs,and the ratio of rmulti-drug resistance to 10 or more drugs was 98.28%(114/116).E.coli was the most sensitive to polymyxin in the selected drug,and the drug resistance rate was 26.72%(31/116).Resistance genes were detected in the isolated polymyxin-resistant E.coli,and the detection rate of mcr-1 was 35.48%(11/31).2.116 strains of Escherichia coli were tested for common genes such as adhesins(987P,F18,F41,K88,K99),enterotoxin(LT,Sta,Stb),Shiga toxin(Stx2e,Stxl,Stx2),hemolysin(HylA),pathogenicity island(FyuA,irp2)and virulence island(eaeA)by PCR.The results showed that 99.13%of the isolates carried the virulence gene,the highest detection rate of irp2 gene is 90.52%,followed by FyuA(75.00%),Stb(49.14%),eaeA(25.86%),HylA(25.00%),K99(15.52%),K88(14.66%),LT(11.21%),F41(6.03%),Stx2e(1.72%),Stx2(1.72%).The Sta,Stxl,987P,and F18 genes were not detected.3.Genetic evolution analysis of 34 strains of Escherichia coli by MLST.The results showed that 10 out of 34 strains belonged to the new ST type,and the remaining 24 strains belonged to 20 different ST types such as ST361,ST10,ST410,ST100,ST1480,and ST209.There was a certain correlation between ST type and drug resistance,but no correlation was found between it and virulence genes.In summary,E.coli isolates in some areas of Guangxi are generally multi-drug resistant and carry a variety of virulence genes,of which 34 isolates have different ST types.This study provides a theoretical basis for the prevention and control of E.coli disease in humans and animals.