一種新開發(fā)的免疫磁性分離方法，使用特異性發(fā)光底物，能夠提供高度敏感的O157:H7大腸桿菌分離解決方案。

這種新方法叫做Captivate O157，使用特異性的抗體包被磁珠，用于分離藥物、食品、動物飼料、飲料和環(huán)境樣品中的O157:H7大腸桿菌。這種細菌是一種十分重要的動物來源的食物傳播的病原菌。主要與自限性的腹瀉有關，也能夠導致嚴重的疾病。傳統(tǒng)分離方法會導致假陰性結果，主要是由于O157:H7菌株的競爭性菌株的干擾。

Captivate O157是由國際診斷集團有限公司(IDG, Bury, UK)研制開發(fā)的。推薦的方案使用了胰化蛋白胨大豆肉湯(MTSB)進行富集，然后使用Captivate分離，在山梨糖MacConkey瓊脂上傳代培養(yǎng)O157磁珠復合物，添加頭孢克肟和亞碲酸鉀。O157:H7大腸桿菌在培養(yǎng)基上呈現(xiàn)出半透明菌落。然后使用乳膠凝集試劑盒或者合適的抗血清進一步確證。
 
Immunomagnetic Method Helps Isolate E Coli
 
A combination of a newly developed immunomagnetic separation method with a specific chromogenic substrate medium provides a highly sensitive solution for the isolation of Escherichia coli O157:H7.

The new method, called Captivate O157, uses specific antibody-coated magnetic beads for the isolation of E coli O157:H7 from pharmaceutical, food, animal feed, beverage, or environmental samples. This strain is one of the most important food-borne pathogens of animal origin. Associated primarily with self-limiting diarrhea, it can also lead to much more serious conditions. Conventional isolation methods can give rise to false-negative results due to the problem of competing flora obscuring E coli O157:H7 colonies.

Captivate O157 was developed by International Diagnostics Group Ltd. (IDG, Bury, UK). The recommended protocol employs enrichment in modified tryptone soy broth (MTSB), followed by separation with Captivate prior to sub-culture of the O157-bead complex on sorbitol MacConkey agar, supplemented with cefixime and potassium tellurite. E coli O157:H7 appear as pale translucent colonies on this medium. Their identity can be confirmed using latex agglutination kits or appropriate antisera.