SubPopulations of Shiga Toxin Producing Escherichia coli: Persistence, Resistance and Pathogenicity

实验 微生物学通常假设细菌种群是同源的 关于抗逆性或基因表达的。然而，在现实中，纯粹 菌株培养是异质的，有一部分细胞存在于 休眠(持续)状态，与主状态相比，具有更强的阻力 人口的主体。此外，在AS培养过程中会错过休眠细胞 它们要么失败了，要么经历了增长延迟。从进化的角度来看， 持续状态是一种更好的对冲，即一定比例的细胞将 在更长的时间内生存，如果人口的条件 很反感。到目前为止，大多数关于坚持的研究都是 关于抗生素治疗后剩余种群的问题。然而， 持久力通常在更广泛的环境中遇到，如土壤，以及 食品系统，例如经过高压处理的食品。这个 残存人口对食品安全的重要性尚不清楚 尽管病原体重新生长或毒力增强的可能性是 两种可能性都有。在拟议的研究计划中，我们将着眼于 志贺毒素产生的休眠(持续、VBNC和耐受)状态 大肠埃希菌(STEC)是一类重要的临床和食源性细菌 病原体。将首次对持久状态进行调查 STEC和诱发或打破休眠状态的触发物被识别。 与之相关的是来自土壤微生物区系的持久性调节剂 以及最终控制病原体的根际：植物之间的相互作用。对于 第一次，我们将演示原噬菌体如何影响持续状态 从而使噬菌体和宿主相互长期存活。对中国传统文化的研究 持久状态将使用最先进的成像技术 与微流控技术相结合，可在 单细胞水平。将生成处于持久状态的单元格并 以便于研究休眠在抗逆性中的作用 压力和裂解噬菌体，以及环境持久性。其影响 这项研究的潜在影响范围很广。从学术角度看 我们将对原噬菌体与宿主的相互作用有更深入的了解。在An上 应用方面，本研究将为食品安全风险评估提供数据 以环境和食物系统中的持久细胞为代表。到目前为止， 风险分析经常指定指定的日志减少，以验证 干预措施(例如，巴氏杀菌)的有效性，而不考虑 残存的幸存者。虽然残留物的含量很低，但在储存过程中可能会生长，或者在宿主内变得更具致病力。该研究将为以下工作提供数据 评估此类风险，进而实现更有效的病原体控制 打破休眠状态的策略。

Experimental microbiology typically assumes bacterial populations are homogenous with respect to resistance to stress or gene expression. However, in reality pure strain cultures are heterogeneous with a proportion of cells existing in a dormant (persistent) state that have enhanced resistance compared to the main body of the population. Moreover, dormant cells are missed during culturing as they either fail or experience delayed growth. In evolutionary terms the persistent state is a kind of “bet hedging” whereby a proportion of cells will survive over extended periods should conditions for the population become adverse. To date, the majority of studies relating to persistence has been with respect to residual populations remaining after antibiotic treatment. Yet, persistence is commonly encountered in the wider environment such as soil, and food systems, such as foods treated with high pressure processing. The significance of residual populations with respect to food safety is unknown although the potential for the re-growth of pathogens or enhanced virulence are both possibilities. In the proposed research program we will look at the dormant (persistent, VBNC and tolerant) state in Shiga Toxin producing Escherichia coli (STEC) a class of significant clinical and foodborne pathogens. For the first time, the persistent state will be investigated in STEC and the triggers that both induce or break the dormant state identified. Of relevance will be the regulators of persistence derived from soil microbiota and rhizosphere that ultimately control pathogen:plant interactions. For the first time, it will be demonstrated how prophage influences the persistent state leading to mutual long term survival of phage and host. Studies of the persistent state will use state-of-the-art imaging techniques in combination with microfluidics that enable manipulation/ observation at the single cell level. Cells in the persistent state will be generated and harvested to facilitate studies on the role of dormancy in resistance to high pressure and lytic phages, in addition to environmental persistence. The impact of the research is potentially wide reaching. From an academic standpoint greater insights into prophage host interactions will be obtained. On an application side the research will provide data to assess the food safety risks represented by persister cells in the environment and food systems. To date, risk analysis has frequently designated a specified log reduction to verify the efficacy of interventions (for example, pasteurization) without taking into account residual survivors. Although present at low levels, residual survivors could grow during storage or become more virulent within the host. The research will provide data to assess such risks and moreover lead to more effective pathogen control strategies through breaking of the dormant state.