EHEC的新型粘附因子研究进展

肠出血性大肠杆菌（enterohemorrhage E-coli，EHEC）是一种重要的人畜共患病，世界各地包括中国都有不同规模的暴发流行。EHEC有多种血清型，其中毒力最强血清型是0157：H7。EHEC0157：H7感染除可使人发生常规腹泻外，还可在5％-10％的病例中引发严重并发症，甚至死亡。该菌是重要的食源性致病菌，危害严重，缺乏有效的防治手段，而抗生素治疗可能会加剧溶血性尿毒症（haemoluticuraemicsyndrome，HUS）。由于以上特点EHEC0157：H7成为世界公共卫生问题，引起微生物学家和公共卫生工作者的广泛关注。目前，临床针对EHEC感染只是对症治疗和适当的抗茵治疗。粘附是EHEC感染宿主细胞的第一步，没有这一步，细菌和宿主肠道细胞之间不会发生任何的相互作用，而且对于许多病原菌来说，粘附具有宿主特异性。本文概述了EHEC的流行病学及粘附机理，并对近年在EHEC研究中的发现一些新型粘附因子和一些假设的定植因子的研究背詈及作用机理作一综述。

Initial Adherence of EHEC

Enterohaemorrhagic Escheriehia coli （EHEC） are emerging zoonotic pathogens, different countries including China had reported different scale of outbreak and sporadic cases. EHEC have many serotypes, O 157：H7 is the most virulent. Human infection is associated with a wide range of clinical illness, including asymptomatic shedding, and about 5%-10% develops to bloody diarrhea, haemorragic colitis, haemolytic uraemic syndrome, and even death. EHEC O157：H7 is found regularly in the faeces of healthy cattle, and is transmitted to humans through contaminated food, water, and direct contact with infected people or animals. Treatment of EHEC O157：H7 infection with antimicrobial agents is controversial, and management of patients is only supportive, because antimicrobial agents may increase the risk of HUS. During the past decade, EHEC O157：H7 has evolved from a clinical novelty to a global public-health concen. Initial adherence to host cells is the first step of the infection of EHEC. Adherence is the first contact between bacteria and intestinal cells without which the other steps cannot occur, and adherence is the basis of host specificity for a lot of pathogens. The aim of this review is to describe the epidemiology and adherence mechanism of enterohemorrhage E.coli （EHEC）, and to summarize several new adhesions and putative colonization factors have found in EHEC during the last few years.