醫療照護機構相關退伍軍人病之臨床診斷與環境監測

Clinical Diagnosis and Environmental Surveillance of Health Care-associated Legionellosis

醫療照護相關退伍軍人病感染，有逐年增加趨勢。存在於醫院供水系統中退伍軍人桿菌，是用來預測退伍軍人病感染風險重要因素。造成退伍軍人病感染病 原菌，包括嗜肺性血清型第1到14型，與非嗜肺性退伍軍人桿菌。醫院的臨床微生物實驗室應具備尿液抗原檢測，與呼吸道退伍軍人桿菌培養相關檢測能力。如果醫院供水系統受到退伍軍人桿菌污染，則肺炎感染病人，應進行退伍軍人桿菌檢測。PCR用於檢測環境水檢體中退伍軍人桿菌存在方法，快速測試是其優點，缺點則是特異性較低，可信度則還有待澄清。可用於供水系統退伍軍人桿菌消毒的許多方法中，文獻證實有效的有銅銀離子消毒法和末端使用過濾器法；二氧化氯和氯胺則正在評估。長效性消毒最好的監測指標，是常規環境退伍軍人桿菌培養，與消毒劑濃度確認。供水系統中出水口退伍軍人桿菌陽性率，能準確預測感染風險。應遵循實證醫學標準，選擇與評估適合於醫院供水系統消毒方法；並針對醫院飲用水與消毒方式，主動進行常規環境培養與消毒濃度監控，以預防醫療照護相關退伍軍人病感染的發生。

The incidence of nosocomial legionellosis appears to be increasing. Presence of Legionella in the hospital’s drinking water system is the important predictor of the risk of contracting Legionnaires’ disease, which is caused by L. pneumophila serogroups 1-14 and non-pneumophila species of Legionella. The hospital’s clinical microbiology laboratory should perform urine antigen testing as well as culturing of Legionella from respiratory tract specimens. If the hospital water supply system is found to harbor Legionella, patients with pneumonia should be tested for Legionella infection. The credibility of the polymerase chain reaction (PCR) for detecting Legionella spp. in environmental water samples has not yet been elucidated. The advantage of PCR is that it enables rapid detection, but the drawback of the technique is its low specificity. Disinfection using copper-silver ionization and point-of-use (POU) filters have proven to be effective methods for disinfecting water supply systems, but methods employing chlorine dioxide and monochloramine are still under evaluation. Routine culturing of environmental samples for detecting Legionella and monitoring of disinfectant concentrations are suggested measures for ensuring the efficacy of long-term disinfection. Positivity rates of Legionella culture in distal sites in water supply system have been applied to predict the infection risks. The institution should follow the evidence-based medicine standards to select and assess suitable disinfection methods. Routine culturing of environmental samples of drinking water and concentration surveillance of disinfectants in the water system should be encouraged to prevent the occurrence of health care-associated Legionella infections.