Association of VTEC O157 and O26 strains with the bovine intestinal mucosa ex vivo

VTEC O157 和 O26 菌株与离体牛肠粘膜的关联

• 批准号: BB/E025153/1
• 负责人: Gad Frankel
• 金额: $ 46.07万
• 依托单位: Imperial College London
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2008
• 资助国家: 英国
• 起止时间: 2008 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=BB%2FE025153%2F1
• 关键词: Association; VTEC; O157; O26; strains

Verotoxigenic Escherichia coli (VTEC) are associated with severe human disease in the UK. The best known member of these pathogenic bacteria is E. coli O157. The most deadly outbreak occurred in Scotland in 1996 but almost every year since E. coli O157 has appeared in the news with outbreaks also reported in England and Wales. Recently, E. coli O26, which can cause similar disease to E. coli O157, has emerged as a significant risk to human health. Cattle infected with VTEC are the major reservoir for human infection. People can be infected from consumption of contaminated food products, by direct contact with animals or from the environment. Although the fact that cattle are the main source of infection, little is currently known about the association of VTEC with the bovine gut. Better understanding is essential in order to develop control measures to minimise the risk of spread. Progress has been hampered not only because large animal experimentation is cumbersome and expensive, but also due to the fact that adherent VTEC bacteria are seen only infrequently following experimental oral challenge of cattle. In vitro organ cultures (IVOC) of gut explants provide a powerful system to study the interaction of pathogenic bacteria with mucosal surfaces of their respective hosts. For several years now the human IVOC system is recognised as the gold standard for assessment of VTEC interactions with human gut mucosa. Technical difficulties stood in the way of developing a bIVOC system that would allow routine, reproducible and large scale investigation of VTEC association with the bovine gut mucosa. Over the past 12 months Dr. Francis Girard, who has vast experience in the porcine IVOC model, optimised culture and infection conditions which led to establishment of a bIVOC system for routine use in our laboratories. bIVOC of different regions of the bovine gut resulted in excellent ultra-structural preservation over 8 h ex vivo incubation. Incubation of bIVOC with VTEC O157 and O26 resulted in efficient colonisation and formation of typical 'attaching & effacing' lesions, particularly on explants from the terminal rectum, indicating that it replicates crucial events during colonisation of intact cattle. This development in our laboratories opens a practical way to efficiently study the bovine phase of VTEC infection. As hundreds of bIVOC can be made from a single animal, our model significantly reduces animal usage. The aims of this project are: 1. To evaluate and compare association of VTEC O157 and O26 strains with bIVOC. 2. To determine if VTEC interact differently with animals of different ages (as epidemiological studies show that young calves are more susceptible). 3. To determine if bacteria recovered from deliberately infected calves show altered colonisation dynamics, patterns and specificities to lab-grown counterparts. This may help to explain why VTEC is efficiently spread between animals on farms. 4. To investigate the molecular and cellular mechanisms involved in binding of VTEC O157 and O26 to bIVOC and the contribution of two critical factors, Tir and TccP, in this process

在英国，产维罗霉素大肠杆菌（VTEC）与严重的人类疾病有关。这些致病菌中最著名的成员是E. coli O157。最致命的爆发发生在1996年的苏格兰，但几乎每年都有E。大肠杆菌O157已经出现在新闻中，英格兰和威尔士也报告了疫情。最近，E. coliO26，其致病性与E.大肠杆菌O157，已成为人类健康的重大风险。感染VTEC的牛是人类感染的主要宿主。人们可以通过食用受污染的食品、直接接触动物或环境而受到感染。虽然牛是主要的感染源，但目前对VTEC与牛肠道的关系知之甚少。为了制定控制措施以最大限度地减少传播风险，更好地了解是必不可少的。进展受到阻碍，不仅是因为大型动物实验繁琐和昂贵，而且还因为在牛的实验性口服挑战后很少看到粘附的VTEC细菌。肠道外植体的体外器官培养（IVOC）提供了一个强大的系统来研究病原菌与其各自宿主的粘膜表面的相互作用。几年来，人类IVOC系统被认为是评估VTEC与人类肠道粘膜相互作用的金标准。技术上的困难阻碍了bIVOC系统的开发，该系统将允许对VTEC与牛肠粘膜的关联进行常规的、可再现的和大规模的研究。在过去的12个月里，在猪IVOC模型方面拥有丰富经验的弗朗西斯吉拉德博士优化了培养和感染条件，从而建立了一个在我们实验室常规使用的bIVOC系统。牛肠道不同区域的bIVOC导致在8小时离体孵育中的极好的超微结构保存。bIVOC与VTEC O157和O26的孵育导致有效的定殖和典型的“附着和消失”病变的形成，特别是在末端直肠的外植体上，表明它在完整牛的定殖过程中复制了关键事件。我们实验室的这一发展为有效研究VTEC感染的牛阶段开辟了一条实用的途径。由于一只动物可以产生数百种bIVOC，我们的模型大大减少了动物的使用。该项目的目标是：1。评价和比较VTEC O157和O26菌株与bIVOC的相关性。2.确定VTEC是否与不同年龄的动物有不同的相互作用（因为流行病学研究表明年幼的小牛更容易受到影响）。3.确定从故意感染的小牛中回收的细菌是否显示出与实验室培养的对应物不同的定殖动力学、模式和特异性。这可能有助于解释为什么VTEC在农场的动物之间有效传播。4.研究VTEC O157和O26与bIVOC结合的分子和细胞机制，以及两个关键因素Tir和TccP在此过程中的作用

项目成果

Dissecting the role of the Tir:Nck and Tir:IRTKS/IRSp53 signalling pathways in vivo.

• DOI: 10.1111/j.1365-2958.2009.06938.x
• 发表时间: 2010-01
• 期刊: Molecular microbiology
• 影响因子: 3.6
• 作者: Crepin VF;Girard F;Schüller S;Phillips AD;Mousnier A;Frankel G
• 通讯作者: Frankel G