School of Veterinary Medicine & Biomedical Sciences, University of Nebraska-Lincoln, Lincoln, NE 68583-0905, USA.
Vet Clin North Am Food Anim Pract. 2010 Mar;26(1):29-56, table of contents. doi: 10.1016/j.cvfa.2009.10.011.
Diarrheagenic Escherichia coli are now broadly placed into 6 classes based on virulence mechanisms. One of these classes, enterotoxigenic E coli, is the most common cause of diarrhea in beef and dairy calves in the first 4 days of life. Two other diarrheagenic classes, enterohemorrhagic E coli (EHEC) and enteropathogenic E coli (EPEC), are important causes of disease in human beings, but less well substantiated causes of diarrhea in calves. E coli strains that cause hemorrhagic colitis and hemolytic uremic syndrome in humans, express high levels of Shiga toxin, cause attaching-effacing (A/E) lesions in intestinal epithelial cells, and possess a specific 60-MDa EHEC plasmid are known as EHEC. One feature EHEC and EPEC have in common is the causation of intestinal epithelial lesions known as attaching and effacing (A/E). Attaching-effacing E coli (AEEC) is a designation for those E coli strains known to cause A/E lesions or at least carry the genes for this trait, and therefore include organisms that fall into either the EHEC or EPEC classes. Because cattle are carriers of many different serotypes of EHEC, much emphasis has been placed on the public health and food safety concerns associated with the fecal shedding of these organisms. However, much less emphasis has been given to their roles as diarrheagenic pathogens of cattle. The goal of this article is to address the question of pathogenicity, with a review that focuses on the results of studies of natural and experimental infections with these organisms. The authors conclude that there is overwhelming evidence that many different serogroups of AEEC are diarrheagenic pathogens of calves.
产毒性大肠杆菌现在根据其毒力机制被广泛分为 6 类。其中一类是产肠毒素性大肠杆菌，是初生犊牛生命的前 4 天发生腹泻的最常见原因。其他两类产毒性大肠杆菌，肠出血性大肠杆菌（EHEC）和肠致病性大肠杆菌（EPEC），是人类疾病的重要原因，但在犊牛中引起腹泻的证据较少。在人类中引起出血性结肠炎和溶血性尿毒综合征的大肠杆菌菌株表达高水平的志贺毒素，在肠上皮细胞中引起黏附破坏（AE）病变，并具有特定的 60-MDa EHEC 质粒，被称为 EHEC。EHEC 和 EPEC 的一个共同特征是引起称为黏附破坏（AE）的肠上皮病变。黏附破坏大肠杆菌（AEEC）是指那些已知引起 AE 病变的大肠杆菌菌株，或者至少携带这种特征的基因，因此包括属于 EHEC 或 EPEC 类的生物体。由于牛是许多不同血清型 EHEC 的携带者，因此非常重视与这些生物体粪便脱落相关的公共卫生和食品安全问题。然而，它们作为牛的致病性病原体的作用却受到的关注较少。本文的目的是解决致病性问题，综述的重点是对这些生物体自然和实验感染的研究结果。作者得出的结论是，有压倒性的证据表明，许多不同的 AEEC 血清群是犊牛的致病性病原体。
