免疫磁捕获-PCR检测大肠杆菌O157

Detection of Escherichia coli O157 by Immunomagnetic Capture-PCR Method

目的使用免疫BMPs,对牛粪标本中的大肠杆菌O157进行免疫磁捕获,再对捕获物进行PCR检测,研究免疫磁捕获-PCR检测牛粪标本中大肠杆菌O157的方法。方法从磁性细菌中获取BMPs,将大肠杆菌O157抗体接种于BMPs表面,制成免疫BMPs。使用免疫BMPs,对大肠杆菌O157∶H7浓度为1×103cfu/g的牛粪标本,进行免疫磁捕获,对捕获物以vt1(Vero毒素1基因)、vt2(Vero毒素2基因)为增扩对象,进行PCR检测。作为对照,相同牛粪标本,直接对牛粪标本以vt1、vt2为增扩对象,进行同样PCR检测。结果相同牛粪标本,经免疫BMPs捕获处理,捕获物的PCR结果显示vt1及vt2基因阳性。而未经免疫磁捕获处理的牛粪标本,直接PCR检测的结果显示阴性。结论对牛粪标本,利用免疫BMPs,可捕获目标抗原,同时还可去除牛粪中存在的PCR反应抑制物等影响因素,提高检测敏感度。

Objective Examination of Escherichia coli O157 from cow dung samples by immunomagnetic capture-PCR method. Methods Bacterial Magnetic Particles（BMPs） were obtained from magnetic bacteria and inoculated with anti-Escherichia coli O157 on the surface to form immune BMPs.Induced by external magnetic field,Escherichia coli O157 ∶H7（1×103cfu/g） in dung samples was captured by using the immune BMPs.The captured was under PCR examination by amplifying the vt1（Vero toxin 1） and vt2（Vero toxin 2） of Escherichia coli O157 ∶H7.And similar dung samples were used to amplify the vt1 and vt2 directly by PCR in the same way as the control. Results The same dung samples showed positive PCR results of vt1 and vt2 genes by immune BMPs immunomagnetic capture treatment,and negative PCR results without the same treatment. Conclusion Immune BMPs was not only to capture the target antigen,but also to remove the PCR reaction inhibitor exists in cow dung and may improve the detection sensitivity.