Detection Of Biofilm Formation Ability,Drug Resistance Genes And Virulence Genes Of Yak-derived And Tibetan Pig-derived E.coli

As an intestinal microorganism,E.coli is more susceptible to environmental factors,and the drug resistance of E.coli is still severe due to its complex serotypes and diverse drug resistance mechanisms.Yaks and Tibetan pigs are more susceptible to bacterial diseases which affecting the lives and health of Tibetan people because of their free-grazing breeding.Therefore,understanding the current status of drug resistance in yak and Tibetan pigs has the practical significance on exploring the mechanism of antibiotics drug resistance and their rational use.In this study,drug sensitivity tests,biofilm formation were carried out to understand the current drug resistance status of 329 yak-derived and Tibetan pig-derived E.coli,and the drug resistance genes,virulence genes and phylogenetic background were analyzed by PCR,the results was as follows:1.Most of the 329 strains of E.coli revealed drug resistance to 24 antibacterials,among which,the resistance rates to streptomycin,chloramphenicol,ampicillin,rifampicin,and oxytetracycline were relatively high,and were sensitive to kanamycin,amikacin,and spectinomycin.The results of biofilm formation ability showed that most of the 329 strains of E.coli had no or weak biofilm-forming ability,and 2 strains showed strong biofilm formation ability.2.The detection results of 28 drug-resistant genes and integrators showed that:21drug-resistant genes and integrators were detected,of which aac（6’）-Ib was the most prevalent gene,followed by sul1 and flo R,with the detection rates over 30%.The otherseven drug-resistant genes to chloramphenicol（cat1,cat2）,β-lactam(bla _CMY-2,bla _SHV),and tetracycline（tet C,tet G,tet X）were not detected.3.The detection results of 15 virulence genes showed that:agn43,sit A,omp T,eae A,bcs A,fim C,LT,Fyu A,and irp2 were all positive,and stx1,stx2,ehx A,bcs B,hly A,and hly E were negative.4.There existed correlation between Tibetan pig-derived E.coli resistant to quinolones and qnr A,and for yak-derived E.coli,the strains resistant toβ-lactam antibiotics existedcorrelation between bla _TEMand bla _DHA.5.The dominant group of yak-derived E.coli was B1,and the dominant group of Tibetan pig-derived E.coli was A.Gene fim C was mainly distributed in group A andB1;sit A and LT were mainly distributed in group A,and all the predominant group of omp T,eae A,Fyu A and irp2 was B1.In summary,the resistance of 329 strains of E.coli is rather serious,by which carried a various drug resistance genes and virulence genes.In addition,the resistance status of E.coli derived from yak and Tibetan pigs is similar,which provides data support for the prevention and treatment of local E.coli disease and the study of drug resistance mechanism.