Temperature diagnostic to identify high risk areas and optimize Legionella pneumophila surveillance in hot water distribution systems

WATER RESEARCH

卷:71

Article

Bedard, Emilie^1,2  Fey, Stephanie¹  Charron, Dominique¹  Lalancette, Cindy²  Cantin, Philippe³  Dolce, Patrick⁴  Laferriere, Celine⁵  Deziel, Eric²  Prevost, Michele¹ 

[1] Polytech Montreal, Dept Civil Engn, Montreal, PQ H3C 3A7, Canada

[2] INRS Inst Armand Frappier, Laval, PQ, Canada

[3] Ctr Expertise Anal Environm Quebec, Quebec City, PQ, Canada

[4] Ctr Hosp Reg Rimouski, Dept Med Microbiol & Infect Dis, Rimouski, PQ, Canada

[5] Univ Montreal, CHU Ste Justine, Dept Microbiol & Immunol Infect Control, Montreal, PQ, Canada

关键词: Legionella pneumophila;    Premise plumbing;    Viable but not culturable (VBNC);    Thermal control;    Temperature profile;    Culturability;   

DOI  :  10.1016/j.watres.2015.01.006

来源: Elsevier

【 摘 要 】

Legionella pneumophila is frequently detected in hot water distribution systems and thermal control is a common measure implemented by health care facilities. A risk assessment based on water temperature profiling and temperature distribution within the network is proposed, to guide effective monitoring strategies and allow the identification of high risk areas. Temperature and heat loss at control points (water heater, recirculation, representative points-of-use) were monitored in various sections of five health care facilities hot water distribution systems and results used to develop a temperature-based risk assessment tool. Detailed investigations show that defective return valves in faucets can cause widespread temperature losses because of hot and cold water mixing. Systems in which water temperature coming out of the water heaters was kept consistently above 60 degrees C and maintained above 55 degrees C across the network were negative for Legionella by culture or qPCR. For systems not meeting these temperature criteria, risk areas for L. pneumophila were identified using temperature profiling and system's characterization; higher risk was confirmed by more frequent microbiological detection by culture and qPCR. Results confirmed that maintaining sufficiently high temperatures within hot water distribution systems suppressed L. pneumophila culturability. However, the risk remains as shown by the persistence of L. pneumophila by qPCR. (C) 2015 Elsevier Ltd. All rights reserved.

【 授权许可】

Free