马乳源大肠杆菌的毒力基因检测和耐药性分析

Virulence Genes Detection and Antimicrobial Resistance Analysis of Escherichia coli Isolated from Horse Milk

[目的]了解新疆伊犁地区某马场乳源大肠杆菌的毒力基因携带情况和药物敏感性。[方法]对采集到的85份马乳进行大肠杆菌的分离纯化、染色镜检、特异性基因phoA的扩增和16S rDNA测序;采用K-B纸片扩散法药敏试验分析马乳源大肠杆菌的耐药性;采用PCR技术检测马乳源大肠杆菌携带的毒力基因、耐药基因及鉴定其所属系统发育群,对大肠杆菌进行生物被膜形成能力检测。[结果]从85份马乳中分离得到6株大肠杆菌,其中3株为A群,3株为B1群;6株大肠杆菌均对青霉素和替米考星耐药;均携带ibeB、yijP、mat、sodA和csgA毒力基因;均未检测到耐药基因;有4株具有生物膜形成能力。[结论]对新疆伊犁地区某马场马乳源大肠杆菌进行初步的毒力基因检测和耐药性分析,发现其对青霉素和替米考星耐药严重,并携带多种毒力基因,具有一定的潜在致病风险。

[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 r DNA.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.