Institute of Food Science and Biotechnology, Department of Food Microbiology and Hygiene, University of Hohenheim, Stuttgart, Germany.
Microbiology of Plant Foods, Agroscope, Waedenswil, Switzerland; Swiss Federal Institute for Forest, Snow, and Landscape Research WSL, Birmensdorf, Switzerland; Department of Life Sciences, Albstadt-Sigmaringen University, Sigmaringen, Germany.
Food Microbiol. 2020 Apr;86:103316. doi: 10.1016/j.fm.2019.103316. Epub 2019 Sep 5.
Human disease outbreaks caused by pathogenic Escherichia coli are increasingly associated with the consumption of contaminated fresh produce. Internalization of enteroaggregative/enterohemorrhagic E. coli (EAEC/EHEC) strains into plant tissues may present a serious threat to public health. In the current study, the ability of the fluorescing Shiga toxin-negative E. coli O104:H4 strain C227/11ϕcu/pKEC2 to adhere to and to internalize into the roots of Lactuca sativa and Valerianella locusta grown in diluvial sand (DS) and alluvial loam (AL) was investigated. In parallel, the soil microbiota was analyzed by partial 16S rRNA gene sequencing. The experiments were performed in a safety level 3 greenhouse to simulate agricultural practice. The adherence of C227/11ϕcu/pKEC2 to the roots of both plant varieties was increased by at least a factor three after incubation in DS compared to AL. Compared to V. locusta, internalization into the roots of L. sativa was increased 12-fold in DS and 108-fold in AL. This demonstrates that the plant variety had an impact on the internalization ability, whereas for a given plant variety the soil type also affected bacterial internalization. In addition, microbiota analysis detected the inoculated strain and showed large differences in the bacterial composition between the soil types.
人类疾病爆发由致病性大肠杆菌引起的越来越多地与食用受污染的新鲜农产品有关。肠聚集性/肠出血性大肠杆菌（EAEC/EHEC）菌株内化进入植物组织可能对公众健康构成严重威胁。在目前的研究中，荧光缺失型 Shiga 毒素大肠杆菌 O104:H4 菌株 C227/11ϕcu/pKEC2 粘附到生菜和苦苣根内并内化的能力在冲积砂（DS）和冲积壤土（AL）中生长进行了研究。同时，通过部分 16S rRNA 基因测序分析了土壤微生物群。实验在安全级别 3 的温室中进行，以模拟农业实践。与 AL 相比，在 DS 中孵育后，C227/11ϕcu/pKEC2 对两种植物根的粘附至少增加了三倍。与 V. locusta 相比，在 DS 中，L. sativa 根内化增加了 12 倍，在 AL 中增加了 108 倍。这表明植物品种对内化能力有影响，而对于给定的植物品种，土壤类型也影响细菌的内化。此外，微生物组分析检测到接种的菌株，并显示出土壤类型之间细菌组成的巨大差异。
