Department of Food Microbiology and Hygiene, Institute of Food Science and Biotechnology, University of Hohenheim, Garbenstr. 28, 70599 Stuttgart, Germany.
Toxins (Basel). 2019 Aug 29;11(9):502. doi: 10.3390/toxins11090502.
The ability to produce enterohemolysin is regarded as a potential virulence factor for enterohemorrhagic (EHEC) and is frequently associated with severe human diseases such as hemorrhagic colitis (HC) and the hemolytic uremic syndrome (HUS). The responsible toxin, which has also been termed EHEC-hemolysin (EHEC-Hly, syn. Ehx), belongs to the Repeats in Toxin (RTX)-family of pore-forming cytolysins and is characterized by the formation of incomplete turbid lysis zones on blood agar plates containing defibrinated sheep erythrocytes. Besides the expression of Shiga toxins (Stx) and the locus of enterocyte effacement (LEE), EHEC-Hly is a commonly used marker for the detection of potential pathogenic strains, although its exact role in pathogenesis is not completely understood. Based on the current knowledge of EHEC-Hly, this review describes the influence of various regulator proteins, explains the different mechanisms leading to damage of target cells, discusses the diagnostic role, and gives an insight of the prevalence and genetic evolution of the toxin.
产肠毒素型大肠埃希菌（Enterohemorrhagic Escherichia coli，EHEC）被认为是一种潜在的毒力因子，与人类严重疾病如出血性结肠炎（Hemorrhagic Colitis，HC）和溶血性尿毒症综合征（Hemolytic Uremic Syndrome，HUS）密切相关。这种致病的毒素也被称为肠出血性大肠埃希菌溶血素（EHEC-Hemolysin，EHEC-Hly，同义词 Ehx），属于重复毒素（Repeats in Toxin，RTX）家族的成孔细胞毒素，其特征是在含有去纤维绵羊红细胞的血琼脂平板上形成不完全浑浊的溶菌区。除了志贺毒素（Shiga Toxins，Stx）和肠上皮细胞脱落（Locus of Enterocyte Effacement，LEE）的表达外，EHEC-Hly 也是检测潜在致病性菌株的常用标志物，尽管其在发病机制中的确切作用尚不完全清楚。基于目前对 EHEC-Hly 的了解，本文综述了各种调节蛋白的影响，解释了导致靶细胞损伤的不同机制，讨论了其诊断作用，并深入了解了该毒素的流行情况和遗传进化。
