南部某區域級教學醫院退伍軍人菌5年改善經驗分享

Revised version-Experience Sharing on the 5-Year Improvement of Legionella at a Regional Teaching Hospital in Southern Taiwan

退伍軍人病（Legionellosis）是由退伍軍人菌（Legionella pneumophila）引起的疾病，水系統是醫療機構中主要的傳播途徑。本院自2011年以來定期監測退伍軍人菌環境狀況。從2020年至2023年，我們在院區新舊大樓中經歷多次退伍軍人菌檢測異常事件。儘管未發現群聚病例，為保障水質安全，我們將檢測頻次提升至每半年一次並進行深入調查。經過調查，主要問題來源為冷水系統餘氯濃度不足（改善前餘氯濃度平均0.16ppm）及熱水系統末端水溫未達50℃。為解決這些問題，我們在院區各棟大樓安裝了水質餘氯自動監控儀，實行自動補充氯，並對冷水系統進行兩階段逐步增加餘氯濃度的調整，最終將餘氯濃度穩定在0.7~0.9ppm，既有效防止退伍軍人菌增生及管路銹蝕，又不會引起氯氣味的抱怨。在熱水系統方面，我們採用了管路溫度控制方法，不僅達到50℃恆溫，還能有效節能減少成本，並降低退伍軍人菌增生的風險。經過長達五年的改善措施，2024年所有常規檢測結果合格，證明這些方法有效防止退伍軍人菌的持續增生。這一改善過程讓我們找到了一套適用於新舊建築的退伍軍人菌防治方法，相較於單次消毒措施，定期維護更能持久保障水質安全，並有效抑制退伍軍人菌的增生。

Legionellosis is an infectious disease caused by Legionella pneumophila, with water systems serving as the primary route of transmission, especially in healthcare settings. Since 2011, our hospital has been regularly monitoring the environmental presence of Legionella bacteria. Between 2020 and 2023, we encountered several instances of abnormal Legionella test results in both new and old buildings on campus. Although no clusters of infection were identified, we proactively increased the testing frequency to once every six months and conducted thorough investigations to ensure water quality and safety. The investigation revealed that the main issues were insufficient residual chlorine levels in the cold water system and inadequate temperatures in the hot water system (below 50°C). To address these problems, we installed automatic residual chlorine monitoring devices in all the buildings on campus, which allowed for the automatic replenishment of chlorine. Additionally, we implemented a two-phase adjustment to gradually increase the residual chlorine concentration in the coldwater system, ultimately stabilizing it at 0.7-0.9 ppm. This level proved effective in preventing Legionella growth while minimizing complaints about chlorine odor. In the hot water system, we implemented a temperature control method that maintained a constant 50°C. This approach not only saved energy and reduced costs but also minimized the risk of Legionella growth. By 2024, after five years of improvements, all regular tests met the required standards, demonstrating that these measures effectively prevented the sustained growth of Legionella. This improvement process enabled us to develop a Legionella prevention method suitable for both new and old buildings. Compared to single disinfection treatments, regular maintenance offers a more sustainable approach to safeguarding water quality and effectively inhibiting the growth of Legionella.