Animal and environmental risk factors for sporadic Shiga toxin-producing Escherichia coli (STEC) infection in England: a case control study for O157, O26 and other STEC serotypes

Most Shiga toxin-producing <i>E. coli</i> (STEC) infections are sporadic. Routine enhanced surveillance questionnaires of confirmed STEC cases in England contained promising data to conduct a case-control study to identify non-food exposures linked to the risk of becoming infected with different STEC serotypes, including O157, O26 and all others; this study pulled eligible cases from the recorded enhanced surveillance data. Controls were recruited from the general population and answered a comparable postal questionnaire. Logistic regression was performed to identify risk factors associated with STEC infection for O157, O26 and other serotype cases. In adjusted models, travel outside of the U.K. and childcare occupations raised the risk of infection for all serotypes. Day trips within the UK, exposure to dogs and contact with soil were linked to lower infection risk. Resident region within England was often linked to decreased risk. Summer season was linked to O157 and O26, but not other STEC. Swimming in the sea was linked to increased risk of infection by O157, but not other types of STEC. Correlations between exposures and infection were similar when the analysis was repeated excluding participants with a history of foreign travel. As the first case-control study in England to include sporadic non-O157 STEC, the varying risk factors between O157 and non-O157 cases suggest there are potentially unique reservoirs for different serotypes.

大多数产志贺毒素大肠杆菌（Shiga toxin-producing E. coli, STEC）感染均为散发性病例。英国针对确诊产志贺毒素大肠杆菌感染病例开展的常规强化监测问卷收集了极具研究价值的数据，可用于开展病例对照研究，以识别与不同血清型产志贺毒素大肠杆菌感染风险相关的非食源性暴露因素，涵盖O157、O26及其他所有血清型；本研究从已记录的强化监测数据中筛选符合条件的病例。对照人群招募自普通人群，需填写与之匹配的邮寄问卷。研究采用Logistic回归分析，识别O157、O26及其他血清型产志贺毒素大肠杆菌感染相关的危险因素。在校正后的模型中，境外旅行与托育相关职业会升高所有血清型产志贺毒素大肠杆菌的感染风险。英国境内当日出行、接触犬只及土壤暴露则与感染风险降低相关。英格兰境内的居住区域通常也与感染风险降低存在关联。夏季与O157、O26型感染相关，但与其他产志贺毒素大肠杆菌血清型感染无关联。海水游泳与O157型感染风险升高相关，但与其他血清型产志贺毒素大肠杆菌感染无关。在剔除有境外旅行史的参与者后重复分析，暴露因素与感染之间的相关性结果保持一致。作为英国首个纳入散发性非O157型产志贺毒素大肠杆菌感染病例的病例对照研究，本研究发现O157型与非O157型感染的危险因素存在差异，提示不同血清型的产志贺毒素大肠杆菌可能拥有各自独特的储存宿主。