摘要
Escherichia coli has become one of the most important causes of calf diarrhea.The aim of this study is to determine the patterns of antimicrobial resistance of E.coli isolates from six cattle farms and to identify prominent resistance genes and virulence genes among the strains isolated from the diarrhea of calves.Antimicrobial susceptibility tests were performed using the disk diffusion method,and PCR was used to detect resistance and virulence genes.The prevalence of multidrug resistant(MDR)E.coli was 77.8%in dairy cattle and 63.6%in beef cattle.There were high resistance rates to penicillin(100%,100%)and ampicillin(96.3%,86.4%)in E.coli from dairy cattle and beef cattle.Interestingly,resistance rate to antimicrobials and distribution of resistance genes in£coli isolated from dairy cattle were higher than those in beef cattle.Further analysis showed that the most prevalent resistance genes were blojm and oodAl in dairy cattle and beef cattle,respectively.Moreover,seven diarrheagenic virulence genes(irp2,fyuA,Stx1,eoeA,F41,K99 and STa)were present in the isolates from dairy cattle,with a prevalence ranging from 3.7%to 22.22%.Six diarrheagenic virulence genes(irp2,fyuA,Stx1,eoeA,hylA and F41)were identified in the isolates from beef cattle,with a prevalence ranging from 2.27%to 63.64%.Our results provide important evidence for better exploring their interaction mechanism.Further studies are also needed to understand the origin and transmission route of£coli in cattle to reduce its prevalence.
基金
This study was supported by the National Science and Technology Ministry(2014BAD13B03-1)
the project supported by the Heilongjiang Province Farms General Administration of China(HNK135-04-03)
This work was supported by a grant from the Heilongjiang Bayi Agricultural University Support Program for San Heng San Zong(TDJH202002).
