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

急诊引起肠道疾病的大肠杆菌根据其毒力因子和致病机制分为致病型。其中一种致病型称为产滋贺毒素E.大肠杆菌（STEC）是指大肠杆菌（E.大肠杆菌，产生至少一种称为滋贺毒素的强效细胞毒素。STEC，特别是血清型O157：H7，是引起食源性感染的重要新兴病原体，导致出血性腹泻和溶血性尿毒综合征（HUS）。然而，非O157菌株也分离自腹泻或HUS患者。相反，从动物和食物中回收的某些STEC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任务，需要开发新的工具来检测农场动物、沿着食物链和终端产品中的STEC。由于并非所有STEC都是致病性的，因此必须表征对人类健康构成威胁的菌株中的特定分子标记。一旦确定，这些标志物将被开发为早期检测食品中致病性STEC污染的分子工具。从长远来看，这将有助于制定潜在的预防和治疗战略。因此，本研究的目的是明确参与STEC致病的毒力因子，并研究其调控机制。我们将专注于基因组和后基因组方法，以确定新的候选人纳入我们改进的诊断工具，安全监测和预防策略。

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.