Persistent Legionella contamination of water faucets in a tertiary hospital in Japan.
OBJECTIVE
The feasibility of the decontamination procedure for Legionella pneumophila of water systems in healthcare facilities varies by water purification and disinfection methods in each country. We evaluated the efficacy of feasible decontamination strategies in Japan.


METHODS
This study was conducted at Tokyo Medical University Hospital (1015 beds) between 2015 and 2018. Samples from the water system and cooling tower were cultured periodically. Hyper-chlorination of cool tap water (>0.2 ppm), increases in the temperature of hot water (>55 °C), and flushing were used as decontamination strategies. The case of healthcare-associated legionellosis was surveyed. Environmental and clinical isolates were genotyped.


RESULTS
1439 environmental samples were collected; 19 (1.3%) samples tested positive for L. pneumophila from water faucets of patient rooms, toilets, waste rooms, and water sourced from wells. Genotyping of 12 isolates confirmed that the same strains were present in eight environmental isolates and two isolates from patients over three years. Although the environmental contamination of the water system was persistent, the number of positive locations of hospital environments gradually decreased; eight in 2015, four in 2016, three in 2017, and four in 2018, respectively.


CONCLUSIONS
Monitoring contamination, hyper-chlorination, controlling temperature, and flushing were effective as a Legionella decontamination strategy.
['Nakamura|Itaru|I|', 'Amemura-Maekawa|Junko|J|', 'Kura|Fumiaki|F|', 'Kobayashi|Takehito|T|', 'Sato|Akihiro|A|', 'Watanabe|Hidehiro|H|', 'Matsumoto|Tetsuya|T|']
D004203:Disinfection D004865:Equipment and Supplies, Hospital D005240:Feasibility Studies D006801:Humans D007564:Japan D016952:Legionella pneumophila D007876:Legionellosis D011446:Prospective Studies D062606:Tertiary Care Centers D014871:Water Microbiology D018508:Water Purification D014881:Water Supply
Decontamination Disinfectant Tap water Legionellosis Infection control Legionnaires’ disease