Development of diagnostic and preventive strategies to reduce Shiga Toxin E. coli (STEC) food contamination risks

引起肠道疾病的大肠杆菌根据其致病的毒力因素和机制被分为几种类型。其中一种病原体，称为产志贺毒素大肠杆菌（STEC），指的是那些至少产生一类强效细胞毒素（称为志贺毒素）的一种成员的大肠杆菌菌株。产大肠杆菌，特别是O157:H7血清型产大肠杆菌，是引起食源性感染的重要新发病原体，可导致出血性腹泻和溶血性尿毒症综合征（HUS）。然而，非o157菌株也从腹泻或溶血性尿毒症患者中分离出来。相比之下，从动物和食物中恢复的某些产大肠杆菌血清型从未与严重的人类疾病相关。预防人类感染是一项重大工作，需要开发新的工具来检测农场动物、食物链和最终产品中的产大肠杆菌。由于并非所有产志贺毒素大肠杆菌都具有致病性，因此必须确定对人类健康构成威胁的菌株中的特定分子标记。一旦确定，这些标记将发展成为早期检测食品中致病性产大肠杆菌污染的分子工具。从长远来看，这将有助于开发潜在的预防和治疗策略。因此，我们的研究目的是表征产志贺毒素大肠杆菌发病机制中涉及的毒力因素并研究它们的调控机制。我们将重点关注基因组和后基因组方法，以确定新的候选方法，纳入我们改进的诊断工具、安全监测和预防战略。

The E. coli that cause enteric diseases are divided into pathotypes, based on their virulence factors and mechanisms by which they cause disease. One of these pathotypes, called Shiga toxin-producing E. coli (STEC), refers to those strains of E. coli that produce at least one member of a class of potent cytotoxins called Shiga toxin. STEC, especially those of serotype O157:H7, are important emerging pathogens causing food-borne infections leading to bloody diarrhea and hemolytic uremic syndrome (HUS). However, non-O157 strains are also isolated from people with diarrhea or HUS. In contrast, certain STEC serotypes recovered from animals and food have never been associated with severe human disease. Prevention of infection in humans is a major undertaking that requires the development of new tools to detect STEC in farm animals, along the food chain and in end products. As not all STEC are pathogenic it is essential to characterize specific molecular markers in strains that represent a threat to human health. Once identified, these markers will be developed into a molecular tool(s) for early detection of pathogenic STEC contamination in food. In the long term this would permit the development of potential preventive and therapeutic strategies. Therefore, the aim of our research to characterise the virulence factors involved in STEC pathogenesis and to study their regulatory mechanisms. We will focus on genomic and post-genomic approaches to identify new candidates for inclusion into our improved diagnostic tools, safety monitoring and preventive strategies.