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它们的毒力因素和致病机制被分为不同的致病类型。其中一种病型称为产志贺毒素的大肠杆菌(STEC)，指的是那些产生至少一种名为志贺毒素的强效细胞毒素的大肠杆菌菌株。STEC，尤其是O157：H7型STEC是一种重要的新兴病原体，可引起食源性感染，导致血性腹泻和溶血性尿毒症综合征(HUS)。然而，非O157菌株也是从腹泻或HUS患者身上分离出来的。相比之下，从动物和食物中恢复的某些STEC血清型从未与严重的人类疾病有关。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、食物链和最终产品中的STEC。由于并不是所有的STEC都是致病的，因此有必要确定对人类健康构成威胁的菌株的特定分子标记。一旦确定，这些标记将被开发成一种分子工具(S)，用于早期检测食品中致病性STEC污染。从长远来看，这将使制定潜在的预防和治疗战略成为可能。因此，本研究的目的是对STEC致病过程中涉及的毒力因子进行表征，并研究其调控机制。我们将专注于基因组和后基因组方法，以确定新的候选对象，以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.