成人急診觀察室 Acinetobacter baumannii 群聚感染及移生事件之疫調及處理經驗

Epidemiological Study of a Cluster of Acinetobacter baumannii Infection/Colonization at an Observation Room of Emergency Department in a Medical Center

南部某醫學中心感染管制組於2005年3月3日常規院內感染監視發現，一名由急診第五觀察室留觀5天後轉入急診加護病房之病人，隔日送驗之痰液培養出多重抗藥性鮑氏不動桿菌 （multidrug-resistant Acinetobacter baumannii （MDR- A. baumannill），為釐清感染來源，回溯調閱2005年1-2月資料，追查曾經住過急診第五觀察室的病人，其痰液檢驗出 MDR- A. baumannii，共計五人（包含上述個案），故疑為群聚感染事件。此5名病人均罹患重症，多數合併呼吸衰竭，並放置氣管內管及使用呼吸器，以脈衝電泳法 （pulsed-field gel electrophoresis; PFGE） 分析4株 MDR- A. baumannii 菌株之基因型，其中2株為同一基因型。為確認感染源，同時採驗急診第五觀察室工作人員、留觀病人及環境檢體共104件，並未發現 MDR- A. baumannii，但有13件培養出 A. baumannii （留觀病人5件，環境8件） ，以 PFGE 基因分型，2株留觀病人菌株及3株環境菌株（呼吸器、床簾、心電圖監視器）為同一基因型。本次調查結果顯示，急診第五觀察室曾有2名病人移生同一株 MDR- A. baumannii，另外，也意外發現一株非多重抗藥性 A. baumannii 已在此區之病人與環境間散佈，在嚴格採取環境淨空消毒、病人集中隔離監控、工作人員落實洗手及接觸隔離等措施後，於2005年3月中旬將此次事件控制並撲滅。（感控雄誌 2009; 19: 214-28）。

An isolate of multidrug-resistant (MDR) Acinetobacter baumannii was found from a patient after being admitted to the 5th observation room (5th OR) at Emergency Department of a medical centre, a ward that accommodate patients awaiting admission. To clarify whether a clonal MDR- A. baumannii spreading at the 5th OR, an epidemiological study was conducted by sampling 104 specimens, included 48 environmental swabs, 29 throat-swabs of personnel and 27 sputum/throat-swabs of patients staying at the 5th OR, for bacterial culture. Medical records of patients who had stayed at the 5th OR shortly before (January-February 2005) and had MDR-A. baumannii isolated from clinical specimens were reviewed. Thirteen specimens (8 sampled from environment and 5 from patients who were staying at the 5th OR) sampled during epidemiological study in March 2005 grew non-MDR A. baumannii isolates. Another five patients who carried MDR-A. baumannii carriage were all critically ill and endotracheal intubation for mechanical ventilation. Four MDR-A. baumannii isolates each from one of these 5 patients were sent to genotypic analysis. Fingerprinting using pussed field gel electrophoresis disclosed that 2 of the 4 MDR-A. baumannii isolates were of the same clone, while 5 non-MDR A. baumannii isolates each found in 2 patients staying at the 5th OR, and surfaces of a ventilator, a bed-side curtain and an electrocardiogram monitor were of another identical clone. The epidemiological study revealed 2 cases of MDR-A. baumannii infection/colonization, and incidentally found that one clonal non-MDR- A. baumannii soreading among patients and in the environment at ED. After implementing infection control measures, included closure of the 5th OR, environmental disinfection, patients cohorting, strict hand-washing practice and contact precautions, this cluster of A. baumannii infection/colonization was eventually controlled by mid-March 2005. (Infect Control J 2009;19:214-28).