Doyle M P
Department of Food Microbiology and Toxicology, University of Wisconsin, Madison.
Int J Food Microbiol. 1991 Apr;12(4):289-301. doi: 10.1016/0168-1605(91)90143-d.
Escherichia coli O157:H7 was conclusively identified as a pathogen in 1982 following its association with two food-related outbreaks of an unusual gastrointestinal illness. The organism is now recognized as an important cause of foodborne disease, with outbreaks reported in the U.S.A., Canada, and the United Kingdom. Illness is generally quite severe, and can include three different syndromes, i.e., hemorrhagic colitis, hemolytic uremic syndrome, and thrombotic thrombocytopenic purpura. Most outbreaks have been associated with eating undercooked ground beef or, less frequently, drinking raw milk. Surveys of retail raw meats and poultry revealed E. coli O157:H7 in 1.5 to 3.5% of ground beef, pork, poultry, and lamb. Dairy cattle, especially young animals, have been identified as a reservoir. The organism is typical of most E. coli, but does possess distinguishing characteristics. For example, E. coli O157:H7 does not ferment sorbitol within 24 h, does not possess beta-glucuronidase activity, and does not grow well or at all at 44-45.5 degrees C. The organism has no unusual heat resistance; heating ground beef sufficiently to kill typical strains of salmonellae will also kill E. coli O157:H7. The mechanism of pathogenicity has not been fully elucidated, but clinical isolates produce one or more verotoxins which are believed to be important virulence factors. Little is known about the significance of pre-formed verotoxins in foods. The use of proper hygienic practices in handling foods of animal origin and proper heating of such foods before consumption are important control measures for the prevention of E. coli O157:H7 infections.
1982年，在与两起与食物相关的异常胃肠道疾病暴发事件相关联后，大肠杆菌O157:H7被最终确认为一种病原体。该微生物现在被公认为食源性疾病的一个重要病因，在美国、加拿大和英国均有暴发事件报道。疾病通常相当严重，可包括三种不同的综合征，即出血性结肠炎、溶血性尿毒综合征和血栓性血小板减少性紫癜。大多数暴发事件都与食用未煮熟的碎牛肉有关，或者较少见的与饮用生牛奶有关。对零售生肉和家禽的调查显示，在1.5%至3.5%的碎牛肉、猪肉、家禽和羊肉中发现了大肠杆菌O157:H7。奶牛，尤其是幼畜，已被确定为该病原体的储存宿主。该微生物具有大多数大肠杆菌的典型特征，但也有独特之处。例如，大肠杆菌O157:H7在24小时内不发酵山梨醇，不具有β-葡萄糖醛酸酶活性，在44 - 45.5摄氏度下生长不良或根本不生长。该微生物没有异常的耐热性；将碎牛肉充分加热以杀死典型的沙门氏菌菌株也会杀死大肠杆菌O157:H7。其致病机制尚未完全阐明，但临床分离株会产生一种或多种志贺毒素，据信这些毒素是重要的毒力因子。对于食物中预先形成的志贺毒素的重要性了解甚少。在处理动物性食品时采用适当的卫生措施以及在食用前对这类食品进行适当加热是预防大肠杆菌O157:H7感染的重要控制措施。
