Gilbert Mark, Monk Curt, Wang Hsiu-Li, Diplock Ken, Landry Lisa
Canadian Field Epidemiology Program, Public Health Agency of Canada.
Can J Public Health. 2008 Jul-Aug;99(4):281-5. doi: 10.1007/BF03403755.
Control measures for enteric outbreaks in child care settings frequently include screening by stool cultures from symptomatic children only. We present evidence from an investigation of Escherichia coli (E. coli) O157:H7 in a daycare in Waterloo, Ontario to support implementation of a mandatory screening policy for all children during an outbreak.
In addition to routine outbreak control measures employed by the health unit, stool samples from all children and staff were collected, with positive E. coli cultures typed by pulsed field gel electrophoresis (PFGE). We conducted a cohort study, using data from the environmental investigation and questionnaires administered to parents and staff, to look for risk factors for infection and to survey parent/staff knowledge regarding appropriate management of diarrhea.
Overall 11 E. coli O157:H7 cases were identified (7 lab-confirmed); 9 were children. No common source of infection was identified. Factors identified as possibly contributing to person-to-person transmission within the daycare included: i) the underreporting and possible attendance of symptomatic children despite alerting parents to the outbreak and requirements to keep symptomatic children at home, ii) possible transmission from an asymptomatic infected child, and iii) inconsistent understanding among parents and staff regarding diarrhea and appropriate management of a child with diarrhea.
DISCUSSION/CONCLUSION: This investigation reveals that in child care settings, E. coli O157:H7 outbreak screening policies based on reported symptoms only may be insufficient. We recommend that such policies be amended to include the collection of at least one stool culture from all children in attendance, regardless of symptom history.
儿童保育机构肠道疾病暴发的控制措施通常仅包括对有症状儿童进行粪便培养筛查。我们展示了安大略省滑铁卢一家日托中心大肠杆菌O157:H7调查的证据，以支持在暴发期间对所有儿童实施强制筛查政策。
除了卫生部门采取的常规暴发控制措施外，还收集了所有儿童和工作人员的粪便样本，对大肠杆菌培养阳性样本进行脉冲场凝胶电泳（PFGE）分型。我们进行了一项队列研究，利用环境调查数据以及向家长和工作人员发放的问卷，寻找感染的风险因素，并调查家长/工作人员对腹泻适当管理的知识。
共确诊11例大肠杆菌O157:H7病例（7例经实验室确认）；9例为儿童。未发现共同感染源。在日托中心内，被确定可能导致人际传播的因素包括：i）尽管已向家长通报疫情并要求有症状儿童居家，但仍有症状儿童报告不足且可能出勤；ii）可能由无症状感染儿童传播；iii）家长和工作人员对腹泻及腹泻儿童适当管理存在理解不一致的情况。
讨论/结论：本次调查表明，在儿童保育机构中，仅基于报告症状的大肠杆菌O157:H7暴发筛查政策可能并不充分。我们建议修订此类政策，包括对所有在园儿童至少采集一次粪便培养样本，无论其症状史如何。
