某區域醫院血液透析室Serratia marcescens血流感染群聚事件調查

黏質沙雷氏桿菌（Serratia marcescens）為嗜氧性革蘭氏陰性桿菌，屬於腸道桿菌科，存在於自然環境中，也是醫院中導致感染的伺機性致病菌，一旦污染醫療設備、用物材料，甚至消毒溶液，都可能造成群聚感染事件。2020年某區域醫院發現血液透析病人血流感染個案增加，5月及6月各有4例感染個案，且血液培養分離出相同致病菌S. marcescens，進而展開群突發事件調查與介入處置。全面檢視感染個案資料及臨床照護流程，調查發現2020年3月至9月共23名血液透析病人血液培養分離出S. marcescens，環境採檢發現感染源為消毒透析機的2%四級銨化合物（quaternary ammonium compounds，QAC）表面消毒劑紙巾盒內部及盒內擦拭紙巾，而工作人員未依規定於每次用罄及每週清潔，使得透析機及人員雙手遭污染，且未落實手部衛生所導致。分析感染個案S. marcescens抗生素敏感性試驗結果幾乎一致，判定為S. marcescens導致的血流感染群聚事件。檢討未能於發生初期即時介入原因，血液透析病人在急門診留取的血液培養被視為入院時已發生的感染而被排除，以致未及時察覺並進一步檢視感染原因。透過加強手部衛生及落實環境清潔消毒等感染管制措施，修訂臨床標準作業流程，輔以定期內外部稽核，強化工作人員感染管制觀念並宣導確實遵循規範，針對臨床分離菌種異常增加情形提高警覺性，並藉由醫療資訊系統輔助定期監測相關數據，以釐清是否有群聚事件發生。經介入措施後，自9月最後一例血流感染病人，至2020年12月無新增S. marcescens血流感染個案，後續追蹤2021至2024年血液透析室皆無異常感染事件發生。

Serratia marcescens is an aerobic gram-negative bacillus belonging to the family Enterobacteriaceae. It is widespread in the natural environment and is an opportunistic pathogen associated with healthcare-associated infections. Contamination of medical equipment, devices, or even disinfectant solutions may lead to outbreak events. In 2020, a regional hospital identified an increase in bloodstream infections among patients undergoing hemodialysis, with four cases reported in both May and June. Blood cultures from these cases yielded the same pathogen, S. marcescens, prompting an outbreak investigation and implementation of control measures. A comprehensive review of clinical data and care processes revealed that from March to September 2020, 23 patients undergoing hemodialysis had blood cultures positive for S. marcescens. Environmental sampling identified the source of infection as contamination of 2% quaternary ammonium compound-containing disinfectant wipes used to clean dialysis machines, including both the interior of the wipe containers and the wipes themselves. Inadequate adherence to protocols, particularly the failure to clean the containers after each depletion and on a weekly basis, resulted in contamination of dialysis machines and the hands of healthcare workers, compounded by poor compliance with hand hygiene practices. Antimicrobial susceptibility testing of the isolates demonstrated highly similar patterns, supporting the identification of a clonal outbreak of S. marcescens bloodstream infections. Delayed recognition of the outbreak was attributed to the initial exclusion of blood cultures obtained in emergency and outpatient settings, which were misclassified as pre-existing infections, hindering timely investigation. Following the implementation of enhanced infection control measures—including reinforcing hand hygiene, strict environmental cleaning and disinfection, revising standard operating procedures, and regular internal and external audits—staff awareness and compliance improved. In addition, increased vigilance for unusual rises in specific pathogens and the use of healthcare information systems for routine surveillance facilitated early detection of potential outbreaks. After these interventions, no new cases of S. marcescens bloodstream infection were identified from the last case in September through December 2020. Continued surveillance from 2021 to 2024 demonstrated no recurrence of abnormal infection events in the hemodialysis unit.