Detection, quantification, and isolation of Escherichia coli O157 by using flow cytometry and fluorescence-activated sorting

灌溉水中的致病菌可能附着在蔬菜上，引起食源性疾病。为了安全供水和食品供应，应查明并清除病原体污染源。为了确定病原体的来源，有必要对活病原体进行特异性检测和分离。本研究的目的是建立一种利用流式细胞术和荧光活化细胞分选（FCM-FACS）从环境水样中特异性检测和分离致病菌的方法。我们使用荧光标记的抗O157抗体特异性检测大肠杆菌O157细胞。检测到的细胞分别分选，在96孔板培养基中培养，鉴定为大肠杆菌O157。即使O157/K12细胞混合物中O157细胞的比例低至0.01%，我们也能特异性检测到O157细胞。此外，我们可以在环境水样中检测到10个细胞/ml的O157细胞。通过将分离细胞的特征与已知来源的大肠杆菌O157数据库中的细胞进行比较，可用于鉴定其来源。

Pathogenic bacteria in irrigation water may attach to vegetables and can cause foodborne diseases. For safe water and food supply, sources of pathogen contamination should be identified and removed. To identify the sources of pathogens, specific detection and isolation of live pathogens is necessary. The objectives of this study were to develop a method to specifically detect and isolate pathogenic bacteria from environmental water samples by using flow cytometry and fluorescence-activated cell sorting (FCM-FACS). We used fluorescence-labeled anti-O157 antibodies to specifically detect E. coli O157 cells. Detected cells were individually sorted and grown in a medium in 96-well plates, and their identities were confirmed as E. coli O157. Even when the proportion of O157 cells in O157/K12 cell mixture was as low as 0.01%, we could specifically detect O157 cells. In addition, we could detect O157 cells present at 10 cells/ml in environmental water samples. Isolated cells can be used to identify their origins by comparing their characteristics to those in known-source E. coli O157 databases.