某醫學中心成人急診加護病房困難梭狀桿菌 （Clostridium difficile）偽群聚感染事件調查

A Pseudo-Outbreak of Clostridium difficile-Associated Diarrhea in Patients Admitted at Intensive-Care Unit of the Emergency Department: Genetic Analysis of the Microbes and Implications of this Pseudo-Outbreak

困難梭狀桿菌（Clostridium difficile）為革蘭氏陽性梭狀桿菌，原是人體腸道正常菌叢中的細菌。由於使用抗生素，導致腸道其他正常菌叢減少，C. difficile因而大量繁殖而造成疾病。本院的成人急診加護病房，於常規監視資料發現，於2007年12月至2008年2月間共發生5例C. difficile腹瀉的感染個案。為避免擴散造成更多的群聚感染，當時斷然採行接觸隔離防護措施，落實消毒性濕洗手，避免非必要抗生素的使用，加強監控可能感染此菌的腹瀉病人，留意其排泄物的處理，及加強環境消毒（高濃度漂白水）。這些C. difficile，經以低頻切位聚合酶鏈鎖反應分子分型分析，確認非同一菌株，持續追蹤六個月後並未發生新增個案，故證實本事件乃偽群聚感染。鑑於此單位過去未曾發現C. difficile相關腹瀉之醫療照護相關感染個案，合理推論這五個案例於住院前C. difficile已移生在病患的腸道中。此次事件可能源於抗生素使用之選擇性壓力造成，因此應盡量避免抗生素使用。本事件也暗示，社會中可能相當程度的C. difficile移生於慢性病患腸道中。如果這個假定被確認，其對台灣社區的影響效應則急待評估，以提供衛生主管機關釐訂因應對策。

Clostridium difficile is part of the normal flora of the gut and may lead to development of C. difficile-associated diarrhea (CDAD) in patients with prior antibiotic exposure. Between December 2007 and February 2008, a cluster of CDAD involving 5 patients admitted from the community to the intensive care unit of Emergency Department (EDICU) of Kaohsiung Chang Gung Memorial Hospital was identified. All of them were elderly, experiencing sepsis with respiratory failure and with prior antibiotic exposure. To contain a presumed CDAD outbreak, infection control measures immediately taken by the EDICU included implementation of contact precautions, hand washing instead of dry-cleaning hand hygiene among staff, minimizing antibiotic use, closely monitoring possible emerging CDAD cases and environmental cleaning. However, subsequent DNA analysis using infrequent-restriction-site PCR (IRS-PCR) disclosed different DNA macro-fragment patterns among these 5 C. difficile isolates, indicating that this was a pseudo-outbreak of CDAD. This pseudo-outbreak suggested the widespread existence of multiclonal C. difficile isolates in the community, Evaluation of the amplitude of C. difficile carriers (especially in elderly with multiple co-morbidities) and impacts of this epidemiologic findings in southern Taiwan is in urgent need, so that the health authorities can map out an effective combat strategy accordingly.