肠出血性大肠埃希氏菌致病机制研究进展

Advance in enterohemorrhagic Escherichia coli pathogenic mechanism

中文关键词:  肠出血性大肠埃希氏菌  定殖  粘附  志贺毒素  免疫逃逸  毒力调控

英文关键词:enterohemorrhagic Escherichia coli  colonization  adhere  Shiga toxin  immune escape  virulence regulation

中文摘要:

      肠出血性大肠埃希氏菌(enterohemorrhagic Escherichia coli, EHEC)是一类能引起轻则水样腹泻、重则溶血尿毒综合征的重要肠道致病菌。EHEC通过感知定殖部位的生物素和核酸浓度、各种物理信号(温度、pH、渗透压)等完成定殖, 随后通过Ⅲ型分泌系统、黏附素等效应蛋白完成对宿主的黏附并造成黏附/脱落损伤, 本文对上述内容进行总结, 并介绍了志贺毒素的分子生物学特征、受体特异性及致病机制, 最后阐述了EHEC如何通过志贺毒素实现免疫逃逸及其在体内的毒力调控机制。通过对EHEC致病机制的总结与解析, 提示我们需要防范和警惕因基因水平转移而产生的新血清型, 感染EHEC可能的促癌效应; 同时不要忽视快乐的情绪、正常的肠道菌群对EHEC的抑制作用。最后需要通过对EHEC的深入研究, 加强对志贺毒素的改造和利用, 使其发挥正向作用。本文旨在确定EHEC防控的关键点, 为食品安全监管提供方向。

英文摘要:

      Enterohemorrhagic Escherichia coli (EHEC) is a kind of important intestinal pathogenic bacteria that can cause watery diarrhea at mild level and hemolytic uremic syndrome at severe level. Firstly, EHEC completes colonization by sensing the concentration of biotin and nucleic acid in the colonization site, and various physical signals (temperature, pH, osmotic pressure); then EHEC accomplishes adhesion to the host and causes adhesion/exfoliation damage through effector proteins from type III secretory system. This paper summarized the above content, introduced the molecular biological characteristics, receptor specificity and pathogenic mechanism of Shiga toxin. Finally, this paper described how EHEC realizes immune escape through Shiga toxin and its virulence regulation mechanism in vivo. Through the analysis of the pathogenic mechanism of EHEC, it is suggested that we need to prevent and be alert to the new serotypes generated by gene horizontal transfer and the possible cancer-promoting effect of EHEC infection, at the same time, don’t ignore the inhibition of happy mood and normal intestinal flora on EHEC. Finally, through in-depth research on EHEC, we need to strengthen the transformation and utilization of Shiga toxin to make it play a positive role, guide vaccine research and development, immunotherapy, and the formulation of clinical treatment plans. Determine the key points of EHEC prevention and control through the study of pathogenic mechanisms, and provide direction for food safety supervision.