TY - JOUR
T1 - Role of hot water temperature and water system use on Legionella control in a tertiary hospital: An 8-year longitudinal study
AU - Gavaldà, Laura
AU - Garcia-Nuñez, Marian
AU - Quero, Sara
AU - Gutierrez-Milla, Carmen
AU - Sabrià, Miquel
PY - 2019/2/1
Y1 - 2019/2/1
N2 - © 2018 Elsevier Ltd Although measures to minimize Legionella colonization in sanitary hot water installations are well established, there is little evidence of their long-term effectiveness in hospital buildings. During an 8-year period, hot water in a large hospital building was sampled monthly in areas with suitable dimensioning and recirculation and in areas with dead legs and low-use taps. In the former areas, the percentage of Legionella-negative samples was 83.2% when the temperature was ≥55%, 64.9% when between 50.1 °C and 54.0 °C, and 51.6% when ≤50 °C (p for trend <0.001). In the highest temperature group, no samples with ≥103 cfu/L were observed. In poorly designed areas, only 44.7% of samples were negative, and 28.9% presented ≥103 cfu/L although reaching 55 °C. In these areas, multivariate analysis showed that if hot water supplies were not used daily, the risk of Legionella colonization was greater than two-fold (odds ratio: 2.84; 95% confidence interval: 1.26–6.41), and the risk of finding Legionella concentrations ≥103 cfu/L was more than three-fold (odds ratio: 3.18; 95% confidence interval: 1.36–7.46), regardless the temperature. These findings indicate that the effectiveness of maintaining sanitary hot water at a minimum temperature of 55 °C is significantly better than that at 50 °C for the environmental control of Legionella but only in installations with suitable dimensioning and recirculation. In installations that do not meet these conditions, high temperatures alone result in insufficient control.
AB - © 2018 Elsevier Ltd Although measures to minimize Legionella colonization in sanitary hot water installations are well established, there is little evidence of their long-term effectiveness in hospital buildings. During an 8-year period, hot water in a large hospital building was sampled monthly in areas with suitable dimensioning and recirculation and in areas with dead legs and low-use taps. In the former areas, the percentage of Legionella-negative samples was 83.2% when the temperature was ≥55%, 64.9% when between 50.1 °C and 54.0 °C, and 51.6% when ≤50 °C (p for trend <0.001). In the highest temperature group, no samples with ≥103 cfu/L were observed. In poorly designed areas, only 44.7% of samples were negative, and 28.9% presented ≥103 cfu/L although reaching 55 °C. In these areas, multivariate analysis showed that if hot water supplies were not used daily, the risk of Legionella colonization was greater than two-fold (odds ratio: 2.84; 95% confidence interval: 1.26–6.41), and the risk of finding Legionella concentrations ≥103 cfu/L was more than three-fold (odds ratio: 3.18; 95% confidence interval: 1.36–7.46), regardless the temperature. These findings indicate that the effectiveness of maintaining sanitary hot water at a minimum temperature of 55 °C is significantly better than that at 50 °C for the environmental control of Legionella but only in installations with suitable dimensioning and recirculation. In installations that do not meet these conditions, high temperatures alone result in insufficient control.
KW - Control measures
KW - Hospital water network
KW - Legionella
KW - Outlets flushing
KW - Water temperature
KW - Water
KW - Temperature
KW - Tertiary Care Centers
KW - Water Supply
KW - Hot Temperature
KW - Longitudinal Studies
KW - Water Microbiology
UR - http://www.mendeley.com/research/role-hot-water-temperature-water-system-legionella-control-tertiary-hospital-8year-longitudinal-stud
U2 - 10.1016/j.watres.2018.11.032
DO - 10.1016/j.watres.2018.11.032
M3 - Article
C2 - 30472548
SN - 0043-1354
VL - 149
SP - 460
EP - 466
JO - Water Research
JF - Water Research
ER -