许多革兰氏阴性茵借助Ⅲ型分泌系统黏附在宿主细胞表面,然后跨越胞膜将特异性蛋白注入宿主细胞内,破坏宿主细胞内的多种信号通路,从而有利于细菌的感染及定殖.在肠致病性大肠杆菌(Enteropathogenic Escherichia coli,EPEC)中,除了肠细胞脱落位点(Locus of entericyte effacement,LEE)毒力岛编码的Ⅲ型分泌系统(Type Ⅲ secretion system,T3SS)外,在分析肠出血性大肠杆菌O157∶H7的基因组序列时发现一个新的Ⅲ型分泌系统,大肠杆菌Ⅲ型分泌系统2(Escherichia coli type Ⅲ secretion system 2,ETT2)毒力岛.研究显示,ETT2可能在大多数菌株中不具有完整的分泌系统功能,但是其对于细菌毒力的发挥具有重要作用.因此,本文简要综述了大肠杆菌ETT2的基因特征、ETT2的分布与流行、ETT2的功能与机制等方面的主要研究进展.%Many Gram-negative bacteria adhere to the surface of the host cell by means of the type Ⅲ secretion system,and then inject the specific protein into the host cell across the membrane,destroying a variety of signal pathways in the host cell,which is beneficial to bacterial infection and colonization.In enteropathogenic Escherichia coli (EPEC),in addition to the intestinal cell shedding site (locus of entericyte effacement,LEE) virulence island encoded type Ⅲ secretion system (T3SS),in the analysis of intestinal hemorrhagic Escherichia coli O157:H7 of the genome sequence found in a new type Ⅲ secretion system,E.coli type Ⅲ secretion system 2 (E.coli type Ⅲ secretion system 2,ETT2)pathogenicity island.Studies have shown that ETT2 may not have a complete secretion system function in most strains,but it has an important effect on the virulence of bacteria.Therefore,this paper briefly reviews the genetic characteristics of E.coli ETT2,the distribution and prevalence of ETT2,the function and mechanism of ETT2 and other aspects of the main research progress.
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