Williams R C, Isaacs S, Decou M L, Richardson E A, Buffett M C, Slinger R W, Brodsky M H, Ciebin B W, Ellis A, Hockin J
Regional Niagara Public Health Department, St. Catharines, Ont.
CMAJ. 2000 May 16;162(10):1409-13.
An outbreak of Escherichia coli O157:H7 infection was identified in the spring of 1998, with a 7-fold increase in the number of laboratory-confirmed E. coli O157:H7 cases in southern Ontario. This prompted an intensive investigation by local, provincial and federal public health officials.
Case interviews of 25 people from southern Ontario were conducted using a broad food history and environmental exposure survey. Laboratory investigations involved both case and food sampling. Specimens of foods sold locally and reportedly consumed by those affected were tested. Common suppliers of suspected foods were identified by cross-referencing suppliers' lists with stores frequented by those who fell ill. A case-control study involving 25 cases and 49 age-matched controls was conducted. This was followed by a comprehensive environmental investigation of the meat processing plant identified as the source of the E. coli.
Thirty-nine outbreak-related cases occurred between April 3 and June 2, 1998. Of the 36 case specimens tested all were positive for E. coli O157:H7. The case-control study identified Genoa salami as the most probable (odds ratio 8 [confidence interval 2-35]) source of the outbreak. Samples of Genoa salami produced by the most commonly identified supplier later tested positive for E. coli O157:H7, and the pathogen matched the same pulsed-field gel electrophoresis pattern and phage type of the case specimens.
Our investigation, which led to a national recall of the brand of dry fermented Genoa salami identified as the source of the outbreak, supports an adherence to stringent manufacturing requirements for fermented meat products. A review of the Canadian standards for fermented meat processing and the effectiveness of their implementation is warranted.
1998年春季确认发生了一起大肠杆菌O157:H7感染疫情，安大略省南部实验室确诊的大肠杆菌O157:H7病例数量增加了7倍。这促使地方、省级和联邦公共卫生官员展开深入调查。
采用广泛的饮食史和环境暴露调查，对安大略省南部的25人进行了病例访谈。实验室调查包括病例和食品采样。对当地销售且据报道受感染者食用过的食品样本进行了检测。通过将供应商名单与患病者常去的商店进行交叉比对，确定了可疑食品的常见供应商。开展了一项病例对照研究，涉及25例病例和49名年龄匹配的对照。随后对被确定为大肠杆菌源头的肉类加工厂进行了全面的环境调查。
1998年4月3日至6月2日期间发生了39起与疫情相关的病例。在检测的36份病例样本中，所有样本的大肠杆菌O157:H7检测均呈阳性。病例对照研究确定热那亚萨拉米香肠是此次疫情最可能的（优势比8 [置信区间2 - 35]）源头。最常被确定的供应商生产的热那亚萨拉米香肠样本后来检测出大肠杆菌O157:H7呈阳性，且该病原体与病例样本的脉冲场凝胶电泳图谱和噬菌体类型相匹配。
我们的调查导致对被确定为疫情源头的干发酵热那亚萨拉米香肠品牌进行全国召回，这支持了对发酵肉制品严格生产要求的坚持。有必要对加拿大发酵肉加工标准及其实施效果进行审查。
