免疫磁分离技术在E.coli O157∶H7检测中的应用

Application of Immunomagnetic Separation to E.coli O157∶H7 Detection

免疫磁分离(i mmunomagnetic separation)技术因其具有选择性好、特异性强、能起到浓缩的作用,已与其他快速检测方法如电化学、光学等方法连用,应用于食品、环境卫生检测等领域。免疫磁分离技术是目前最有推广价值的技术之一。文章通过比较不同的E.coli O157∶H7-免疫磁珠(immunomagnetic beads,I MB)浓度配比、E.coli O157∶H7与Bacillus subtilis不同的体积比下的免疫磁分离的捕获率,得出当E.coli O157∶H7-I MB浓度配比为1∶30时,捕获率近100%,即所有的目标菌均可被捕获到;在总体积不变、IMB的加入量一定的情况下,随着Bacillus subtilis比例的增加,捕获率出现先下降后上升的情况。同时,将IMS与ATP生物发光法结合起来,对不同浓度的E.coliO157∶H7进行了检测,得出该方法与传统的平板培养法具有很好的线性相关性,则R2=0.9882,检测限可低达102CFU.mL-1。

In the present paper, the capture efficiencies of four different proportions of E. coli O157 ： H7 and immunomagnetic beads （IMB） （1 ： 6.34, 1 ： 12.69, 1 ： 25.38 and 1 ： 30.07） and three different proportions orE. coli O157 ： H7 and Bacillus suhtilis（0. 3 mL ： 0.1 mL, 0.2 mL ： 0.2 mL and 0.1 mL ： 0. 3 mL）were compared, with the total volume and capacity of IMB remaining constant. It was revealed that the capture efficiency could reach 100% when the proportion of E. coli O157 ： H7 and IMB was 1 ： 30, meaning that almost all targets E. coli O157 ： H7 could be captured at 1 ： 30, and that the capture efficiency decreased and then increased with the number of Bacillus subtilis increasing. Moreover, the combination of ATP bioluminescence and IMS was correlated well with conventional culture methods, R^2 = 0. 988 2, and the detection limit was as low as 10^2 CFU · mL^-1.