Shiga toxin producing E. coli are a problem for food producers. STEC's require a combination of virulence factors to cause disease, so ideally detection techniques should detect the presence of multiple virulence factors in a single cell directly from food. Droplet Digital PCR (ddPCR) is commonly used to quantify the number of copies of a gene in a sample, moreover it is able to link two genes to the same piece of DNA. Here stx and an O-antigen specific gene are detected simultaneously with taqman probes confirming that the cells are intact as well as distinguishing between strains based on their genotype. Using ddPCR E. coli O157:H7 and O104:H4 are quantified from apple juice, milk and spinach washings without an enrichment step, the detection limit of ddPCR in apple juice was 2 cfu/mL. Also, ddPCR was used to detect pathogenic bacterial cells in the presence of background strains which shared one or none of the target genes, including avirulent strains. Whole cell ddPCR is compared to several DNA extraction techniques demonstrating that whole cell ddPCR is more reliable for linking genes within an organism. Whole cell ddPCR is a promising technique for the rapid and specific detection of foodborne pathogens.

中文翻译：

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通过液滴数字PCR检测食品中的肠出血性大肠杆菌，以检测单个基因组中的同时毒力因子。

产生志贺毒素的大肠杆菌是食品生产者的难题。STEC需要使用多种致病因子来引起疾病，因此理想的检测技术应直接从食物中检测单个细胞中多种致病因子的存在。液滴数字PCR（ddPCR）通常用于量化样品中基因的拷贝数，而且它能够将两个基因连接到同一条DNA。在此，用taqman探针同时检测到stx和O抗原特异性基因，从而确认细胞是完整的，并根据其基因型在菌株之间进行区分。使用ddPCR在没有富集步骤的情况下，从苹果汁，牛奶和菠菜洗涤液中对大肠杆菌O157：H7和O104：H4进行定量，苹果汁中ddPCR的检测限为2 cfu / mL。也，ddPCR用于在背景菌株存在下检测病原细菌细胞，这些背景菌株共享一个或一个目标基因，包括无毒力菌株。将全细胞ddPCR与几种DNA提取技术进行了比较，证明了全细胞ddPCR对于连接生物体内的基因更为可靠。全细胞ddPCR是一种快速，特异性检测食源性病原体的有前途的技术。