Abstract：
Legionella is an opportunistic waterborne pathogen that causes Legionnaires\' disease. It poses a significant public health risk, especially to vulnerable populations in health care facilities. It is ubiquitous in manufactured water systems and is transmitted via inhalation or aspiration of aerosols/water droplets generated from water fixtures (e.g., showers and hand basins). As such, the effective management of premise plumbing systems (building water systems) in health care facilities is essential for reducing the risk of Legionnaires\' disease. Chemical disinfection is a commonly used control method and chlorine-based disinfectants, including chlorine, chloramine, and chlorine dioxide, have been used for over a century. However, the effectiveness of these disinfectants in premise plumbing systems is affected by various interconnected factors that can make it challenging to maintain effective disinfection. This systematic literature review identifies all studies that have examined the factors impacting the efficacy and decay of chlorine-based disinfectant within premise plumbing systems. A total of 117 field and laboratory-based studies were identified and included in this review. A total of 20 studies directly compared the effectiveness of the different chlorine-based disinfectants. The findings from these studies ranked the typical effectiveness as follows: chloramine > chlorine dioxide > chlorine. A total of 26 factors were identified across 117 studies as influencing the efficacy and decay of disinfectants in premise plumbing systems. These factors were sorted into categories of operational factors that are changed by the operation of water devices and fixtures (such as stagnation, temperature, water velocity), evolving factors which are changed in-directly (such as disinfectant concentration, Legionella disinfectant resistance, Legionella growth, season, biofilm and microbe, protozoa, nitrification, total organic carbon(TOC), pH, dissolved oxygen(DO), hardness, ammonia, and sediment and pipe deposit) and stable factors that are not often changed(such as disinfectant type, pipe material, pipe size, pipe age, water recirculating, softener, corrosion inhibitor, automatic sensor tap, building floor, and construction activity). A factor-effect map of each of these factors and whether they have a positive or negative association with disinfection efficacy against Legionella in premise plumbing systems is presented. It was also found that evaluating the effectiveness of chlorine disinfection as a water risk management strategy is further complicated by varying disinfection resistance of Legionella species and the form of Legionella (culturable/viable but non culturable, free living/biofilm associated, intracellular replication within amoeba hosts). Future research is needed that utilises sensors and other approaches to measure these key factors (such as pH, temperature, stagnation, water age and disinfection residual) in real time throughout premise plumbing systems. This information will support the development of improved models to predict disinfection within premise plumbing systems. The findings from this study will inform the use of chlorine-based disinfection within premise plumbing systems to reduce the risk of Legionnaires disease.
摘要：
军团菌是导致军团菌病的机会性水传播病原体。它构成了重大的公共卫生风险，特别是医疗机构中的弱势群体。它在人造水系统中无处不在，并通过吸入或吸入由水固定装置产生的气溶胶/水滴传播（例如，淋浴和手盆)。因此，有效管理卫生保健设施中的房地管道系统（建筑供水系统）对于降低军团病的风险至关重要。化学消毒是一种常用的控制方法和氯基消毒剂，包括氯，氯胺，还有二氧化氯,已经使用了一个多世纪。然而,这些消毒剂在前提管道系统中的有效性受到各种相互关联的因素的影响，这些因素可能使维持有效的消毒具有挑战性。本系统文献综述确定了所有研究，这些研究检查了影响前提管道系统中氯基消毒剂的功效和腐烂的因素。本综述共确定了117项现场和实验室研究。共有20项研究直接比较了不同氯基消毒剂的有效性。来自这些研究的发现将典型有效性排序如下:氯胺>二氧化氯>氯。在117项研究中，总共确定了26个因素会影响前提管道系统中消毒剂的功效和腐烂。这些因素被分类为操作因素的类别，这些操作因素会因水装置和固定装置的操作而改变（例如停滞，温度,水速)，直接变化的演变因素(如消毒剂浓度，军团菌消毒剂抗性,军团菌生长,季节,生物膜和微生物，原生动物,硝化，总有机碳(TOC)pH值,溶解氧（DO），硬度,氨,和沉积物和管道沉积物)和不经常变化的稳定因素(如消毒剂类型、管道材料,管道尺寸,管道年龄，水再循环,柔软剂,缓蚀剂,自动感应水龙头,建筑楼层,和建筑活动)。给出了每个因素的因素效应图，以及它们与前提管道系统中针对军团菌的消毒功效是否具有正相关或负相关。还发现，通过改变军团菌物种的消毒抗性和军团菌的形式（可培养/可行但不可培养，自由生活/生物膜相关，变形虫宿主内的细胞内复制）。未来的研究需要利用传感器和其他方法来测量这些关键因素(如pH、温度,停滞,水龄和消毒残留)在整个前提管道系统中实时。此信息将支持改进模型的开发，以预测房屋管道系统内的消毒。这项研究的结果将为在前提管道系统中使用氯基消毒提供信息，以降低军团病的风险。
