Persistent Legionella contamination of water faucets in a tertiary hospital in Japan. (April 2020)

• Record Type: Journal Article
• Authors: Nakamura, Itaru; Amemura-Maekawa, Junko; Kura, Fumiaki; Kobayashi, Takehito; Sato, Akihiro; Watanabe, Hidehiro; Matsumoto, Tetsuya
• Is Part Of: International journal of infectious diseases. Volume 93(2020)
• Page Start: 300
• Page End: 304
• Publication Date: 2020-04
• Subjects: Tap water -- Legionellosis -- Legionnaires' disease -- Infection control -- Disinfectant -- Decontamination; Communicable diseases -- Periodicals; Communicable Diseases -- Periodicals; Communicable diseases; Periodicals; Electronic journals; 616.9
• DOI: 10.1016/j.ijid.2020.03.002
• Languages: English
• ISSNs: 1201-9712

Abstract

Highlights: We evaluated feasible Legionella decontamination strategies in Japan. Monitoring contamination, hyper-chlorination, heating, and flushing were performed. One thousand four hundred thirty-nine environmental samples were collected; 19 (1.3%) samples tested positive. Eight environmental isolates and two clinical isolates were genetically indistinguishable. The number of positive locations of hospital environments gradually decreased. Abstract: 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.