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Abstract：
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.
摘要：
虽然减少卫生热水设施中军团菌定植的措施已经确立,几乎没有证据表明它们在医院建筑中的长期有效性。在八年期间,每月在具有适当尺寸和再循环的区域以及具有死腿和低使用水龙头的区域对大型医院大楼中的热水进行采样。在以前的地区，当温度≥55%时，军团菌阴性样本的百分比为83.2%，在50.1°C至54.0°C之间时，为64.9%，≤50°C时为51.6%(趋势p<0.001)。在最高温度组中，未观察到≥103cfu/L的样品。在设计不良的地区，只有44.7%的样本是阴性的，和28.9%呈现≥103cfu/L，尽管达到55°C。在这些地区,多变量分析表明，如果不每天使用热水供应，军团菌定植的风险大于2倍(比值比:2.84;95%置信区间:1.26-6.41),发现军团菌浓度≥103cfu/L的风险超过三倍（比值比：3.18；95％置信区间：1.36-7.46），不管温度。这些发现表明，对于军团菌的环境控制，在55°C的最低温度下保持卫生热水的有效性明显优于50°C，但仅在具有合适尺寸和再循环的装置中。在不符合这些条件的装置中，仅高温就会导致控制不足。
