Escherichia coli O157:H7 stress and virulence gene expression on Romaine lettuce using comparative real-time PCR
Escherichia coli O157:H7 stress and virulence gene expression on Romaine lettuce using comparative real-time PCR
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DOI：
10.1016/j.mimet.2009.02.010
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发表时间：
2009-05-01
影响因子：
2.2
通讯作者：
Thompson, Stacey
中科院分区：
文献类型：
--
作者：
Carey, Christine M.;Kostrzynska, Magdalena;Thompson, Stacey
由于新鲜农产品被大肠杆菌O157：H7污染而导致的食源性疫情日益引起人们的关注。特别是绿叶蔬菜，包括生菜和菠菜，容易受到灌溉用水、粪便以及食品加工和储存做法的污染。用平板计数法评价了大肠杆菌O157：H7和天然微生物群在罗曼生菜上4℃和15℃贮藏9天内的存活情况。采用两步逆转录比较实时定量聚合酶链式反应(RT-FQ)检测志贺毒素A亚单位(stx1A和stx2A)、内膜蛋白(EaeA)、鞭毛蛋白(Flic)、S(Sigma)等基因在O157：H7中的表达。结果表明，贮藏温度由15℃降至4℃，差异显著(P<0.05)。
Foodborne outbreaks attributed to the contamination of fresh produce with Escherichia coli O157:H7 are a growing concern. In particular, leafy-green vegetables, including lettuce and spinach, are susceptible to contamination by irrigation water, manure, and food processing and storage practices. The survival of E. coli O157:H7 and natural microflora on Romaine lettuce stored at 4 degrees C and 15 degrees C over a 9-day period was evaluated by plate counts. A two-step reverse-transcription comparative quantitative real-time PCR assay was employed to evaluate expression of genes coding for the A subunit of Shiga-toxin 1 and 2 (stx1A and stx2A), intimin (eaeA), flagellin (fliC), sigma(S) - general stress sigma factor (rpoS) and iron superoxide dismutase (sodB) in E. coli O157:H7. Results indicate that reducing the storage temperature from 15 degrees C to 4 degrees C significantly (P