Abstract:

[Objective] The present study aimed to assess the prevalence of virulence genes and the antimicrobial susceptibility profile of Escherichia coli （E. coli） isolated from horse milk in a farm in Ili Kazak Autonomous Prefecture of Xinjiang, China. [Method] A total of 85 horse milk samples were collected and subjected to isolation, purification and staining microscopy for E. coli strains. The isolates were molecularly identified by PCR and sequencing of phoA gene and 16S rDNA. The antimicrobial susceptibility tests of the isolates were carried out using K-B disk diffusion method. The presence of virulence genes and antimicrobial resistance genes of the isolates were detected, and phylogenetic groups of the isolates were determined by PCR assay. The biofilm formation ability of the isolates was evaluated. [Result] Six strains of E. coli were isolated from the 85 horse milk samples, of which 3 strains were group A and 3 strains were group B1. All the 6 isolates were resistant to penicillin and tilmicosin, and harbored virulence genes of ibeB, yijP, mat, sodA and csgA. No antimicrobial resistance genes were detected. Four isolates exhibited biofilm formation ability. [Conclusion] The E. coli isolates from horse milk in the farm in Ili Kazak Autonomous Prefecture had high-level resistance to penicillin and tilmicosin and carried a variety of virulence genes, suggesting certain potential pathogenic risks.

Key words: horse milk, Escherichia coli, virulence genes, antimicrobial susceptibility analysis