Disinfection of hot water systems is critical for reducing Legionnaires’ disease in high-risk buildings. The use of neutral electrolysed oxidising water (NEOW) is a promising method for the control of microorganisms in hot water systems. However, full-scale evaluations of the efficacy of NEOW devices to control Legionella pneumophila are currently lacking. The aim of this study was to assess the effectiveness of a NEOW device in reducing L. pneumophila in a hotel water network.

Water samples (n = 67) were collected from different sites of a hotel distribution system before and after the installation of the NEOW device at the 1st, 4th, 8th and 12th week. Detection of L. pneumophila was performed comparing culture, qPCR and PMA-qPCR methods. Total bacterial counts (22 °C and 37 °C), Pseudomonas spp. and physico-chemical parameters were also monitored.

The NEOW treatment resulted in a reduction of the amount of L. pneumophila positive samples (−32%) and of the number of heavily contaminated points (>104 CFU/L and >103 CFU/L) (−100% and −96%, respectively). Treatment maintained L. pneumophila at low levels (<102 CFU/L), which do not require specific intervention measures. The effectiveness of the disinfection system was also confirmed by PMA-qPCR (p < 0.001). The use of PMA resulted in a signal decrease in almost all samples upon the disinfection treatment.

The NEOW disinfection device appears to be a promising approach to reduce the colonisation of hot water systems by L. pneumophila; however, further investigations are needed to ascertain its efficiency over longer time periods.

热水系统的消毒对于减少高风险建筑物中的退伍军人病至关重要。使用中性的电解氧化水（NEOW）是控制热水系统中微生物的一种有前途的方法。但是，目前尚缺乏对NEOW装置控制嗜肺军团菌的功效的全面评估。本研究的目的是评估在减少NEOW装置的效率嗜肺军团菌在旅馆水网络。

在第一周，第四周，第八周和第十二周安装NEOW设备之前和之后，从酒店分配系统的不同地点收集了水样本（n = 67）。比较培养，qPCR和PMA-qPCR方法进行了嗜肺乳杆菌的检测。细菌总数（22°C和37°C），假单胞菌属。并监测理化参数。

NEOW处理导致减少了嗜肺乳杆菌阳性样本的数量（-32％）和严重污染点的数量（> 104 CFU / L和> 103 CFU / L）（-100％和-96％） ， 分别）。治疗可使肺炎链球菌维持在较低水平（<102 CFU / L），这不需要采取特殊的干预措施。PMA-qPCR也证实了消毒系统的有效性（p <0.001）。在消毒处理后，PMA的使用导致几乎所有样品的信号下降。

NEOW消毒装置似乎是减少嗜肺乳杆菌（L. pneumophila）对热水系统的定殖的有前途的方法; 但是，需要进一步研究以确定其在较长时间段内的效率。