Abteilung Mikrobiologie, Universität Osnabrück, Osnabrück, Germany.
Department of Pediatrics, Division of Host-Microbe Systems and Therapeutics, University of California at San Diego, San Diego, California, USA.
Appl Environ Microbiol. 2020 Apr 1;86(8). doi: 10.1128/AEM.02757-19.
is a foodborne pathogen often leading to gastroenteritis and is commonly acquired by consumption of contaminated food of animal origin. However, frequency of outbreaks linked to the consumption of fresh or minimally processed food of nonanimal origin is increasing. New infection routes of by vegetables, fruits, nuts, and herbs have to be considered. This leads to special interest in interactions with leafy products, e.g., salads, that are mainly consumed in a minimally processed form. The attachment of to salad is a crucial step in contamination, but little is known about the bacterial factors required and mechanisms of adhesion. possesses a complex set of adhesive structures whose functions are only partly understood. Potentially, may deploy multiple adhesive strategies for adhering to various salad species and other vegetables. In this study, we systematically analyzed the contributions of the complete adhesiome, of lipopolysaccharide (LPS), and of flagellum-mediated motility of serovar Typhimurium (STM) in adhesion to (corn salad). We deployed a reductionist, synthetic approach to identify factors involved in the surface binding of STM to leaves of corn salad, with particular regard to the expression of all known adhesive structures, using the Tet-on system. This work reveals the contribution of Saf fimbriae, type 1 secretion system-secreted BapA, an intact LPS, and flagellum-mediated motility of STM in adhesion to corn salad leaves. Transmission of gastrointestinal pathogens by contaminated fresh produce is of increasing relevance to human health. However, the mechanisms of contamination of, persistence on, and transmission by fresh produce are poorly understood. We investigated the contributions of the various adhesive structures of STM to the initial event in transmission, i.e., binding to the plant surface. A reductionist system was used that allowed experimentally controlled surface expression of individual adhesive structures and analyses of the contribution to binding to leave surfaces of corn salad under laboratory conditions. The model system allowed the determination of the relative contributions of fimbrial and nonfimbrial adhesins, the type 3 secretion systems, the O antigen of lipopolysaccharide, the flagella, and chemotaxis of STM to binding to corn salad leaves. Based on these data, future work could reveal the mechanism of binding and the relevance of interaction under agricultural conditions.
是一种食源性病原体，常导致肠胃炎，通常通过食用受污染的动物源性食物而感染。然而，与食用新鲜或轻度加工的非动物源性食物有关的疫情频率正在增加。蔬菜、水果、坚果和香草等植物也可能成为新的感染途径，需要加以考虑。这就使得人们对 与叶菜类产品（如沙拉）的相互作用特别感兴趣，这些产品主要以轻度加工的形式食用。 附着在沙拉上是污染的关键步骤，但对粘附所需的细菌因素和机制知之甚少。 拥有一套复杂的粘附结构，其功能仅部分被理解。 可能会部署多种粘附策略，以粘附到各种沙拉品种和其他蔬菜上。在这项研究中，我们系统地分析了 血清型鼠伤寒沙门氏菌（STM）全粘附组、脂多糖（LPS）和鞭毛介导的运动在粘附到 （玉米沙拉）中的作用。我们采用简化的综合方法，利用 Tet-on 系统，研究 STM 与玉米沙拉叶片表面结合的因素，特别关注所有已知粘附结构的表达。这项工作揭示了 Saf 菌毛、I 型分泌系统分泌的 BapA、完整 LPS 和 STM 鞭毛介导的运动在粘附到玉米沙拉叶片中的贡献。通过受污染的新鲜农产品传播胃肠道病原体对人类健康的相关性日益增加。然而，对 的污染、在其上的持久性以及通过新鲜农产品传播的机制知之甚少。我们研究了 STM 的各种粘附结构对初始事件（即与植物表面结合）的贡献。使用简化系统，可在实验室条件下，对单个粘附结构的实验控制表面表达和对玉米沙拉叶片表面结合的贡献进行分析。该模型系统允许确定菌毛和非菌毛粘附素、III 型分泌系统、脂多糖的 O 抗原、鞭毛和 STM 趋化性对与玉米沙拉叶片结合的相对贡献。基于这些数据，未来的工作可以揭示结合的机制以及在农业条件下相互作用的相关性。
