中文摘要：

目的建立一种无需增菌即能快速、灵敏检测大肠杆菌O157：H7的新方法。方法制备一种表面包被大肠杆菌O157：H7单克隆抗体的纳米级免疫磁颗粒，用于样品中菌体的富集和分离；制备一种表面分别标记有大肠杆菌O157：H7多克隆抗体和生物素化核酸探针的胶体金颗粒；利用生物素一亲和素．酶系统信号放大作用，达到对目标菌的快速、灵敏检测。结果该方法可在1h内完成菌体的分离和检测，检测限为10cfu／ml。结论该检测体系基于功能化纳米粒子进行菌体分离及信号放大，具有检测时间短、灵敏度高、操作简便等优点，在环境、食品检测，临床诊断和流行病监测中具有广泛的应用前景。

英文摘要：

Objective To develop a rapid and ultrasensitive method for the detection of E.coli O157：H7 without multiplication. Methods Monoclonal antibody of E .coli O157：H7 labeled dextran-coated iron oxide nanoparticles（DCIONP） were prepared for the enriching and isolation of target bacteria,functional gold nanoparticles were prepared with polyclonal antibody of E.coli O157：H7 and considerable biotin labeled Oligonucleotide （beacon DNA）, and biotin-streptavidin-HRP were utilized as a signal amplification system to implement the destination of rapid and ultrasensitive detection. Results The detection could be controlled within 1 h with the sensitivity limits of 10 cfu/ml or even less. Conclusion A rapid and ultrasensitive detection method for E. coli O157：H7 is built based on two functional nanoparticles.