Khan Asis, Datta Simanti, Das S C, Ramamurthy T, Khanam J, Takeda Y, Bhattacharya S K, Nair G B
National Institute of Cholera & Enteric Diseases (ICMR), Kolkata, India.
Indian J Med Res. 2003 Jul;118:1-24.
Shiga toxin producing Escherichia coli (STEC) is a newly emerged pathogen that has been the focus of immense international research effort driven by its recognition as a major cause of large scale epidemics and thousands of sporadic cases of gastrointestinal illness. It produces a severe bloody diarrhoea that is clinically distinct from other types of diarrhoeal diseases caused by other enteric pathogens. One of the most important areas of current exploration concerns how STEC enters our food chain, an investigational avenue that begins with the ecology of STEC in animals and in the environment. A variety of foods have been identified as vehicles of STEC-associated illness and this makes the organism one of the most serious threats to the food industry in recent years. The pathogenesis of STEC is multifactorial and involves several levels of interaction between the bacterium and the host. STEC strains carry a set of virulence genes that encode the factors for attachment to host cells, elaboration of effective molecules and production of two different types of Shiga toxins. These genes are found in the locus of enterocyte effacement (LEE), lamboid phages, and a large virulence associated plasmid. The publication of the complete genome sequence of Esch. coli O157:H7 chromosome offers a unique resource that will help to identify additional virulence genes, to develop better methods of strain detection and in the understanding of the evolution of Esch. coli through comparison with the genome of the non-pathogenic laboratory strain Esch. coli K-12. These research efforts in turn, should lead to development of new potent and cost effective anti-Stx therapies or vaccines and thereby major improvement in human health world-wide.
产志贺毒素大肠杆菌（STEC）是一种新出现的病原体，由于其被公认为大规模疫情和数千例散发性胃肠疾病的主要病因，已成为国际上大量研究工作的重点。它会引发严重的血性腹泻，在临床上与其他肠道病原体引起的其他类型腹泻疾病不同。当前探索的最重要领域之一涉及STEC如何进入我们的食物链，这一研究途径始于STEC在动物和环境中的生态学。多种食物已被确定为STEC相关疾病的传播媒介，这使得该病原体成为近年来食品行业面临的最严重威胁之一。STEC的发病机制是多因素的，涉及细菌与宿主之间的多个相互作用层面。STEC菌株携带一组毒力基因，这些基因编码附着于宿主细胞的因子、有效分子的产生以及两种不同类型志贺毒素的产生。这些基因存在于肠上皮细胞脱落位点（LEE）、λ噬菌体和一个与毒力相关的大质粒中。大肠杆菌O157:H7染色体完整基因组序列的公布提供了一种独特的资源，这将有助于识别其他毒力基因，开发更好的菌株检测方法，并通过与非致病性实验室菌株大肠杆菌K-12的基因组比较来理解大肠杆菌的进化。这些研究工作反过来应会导致开发出新的有效且经济高效的抗Stx疗法或疫苗，从而在全球范围内大幅改善人类健康。
