Lasheras Agnes, Boulestreau Helene, Rogues Anne-Marie, Ohayon-Courtes Celine, Labadie Jean-Claude, Gachie Jean-Pierre
Service Hygiène Hospitalière, Hôpital Pellegrin, CHU Bordeaux, Bordeaux cedex, France.
Am J Infect Control. 2006 Oct;34(8):520-5. doi: 10.1016/j.ajic.2006.03.007.
The reservoir for hospital-acquired Legionnaires' disease has been shown to be the potable water distribution system. The objectives of the present study were as follows: (1) to examine the possible relationship between physical-chemical characteristics of water such as temperature, pH, hardness, conductivity, and residual chlorine and the presence of amoebae as growth-promoting factors for Legionella species and (2) to determine eradication measures for water distribution systems to seek ways of reducing the risk of legionellosis. Ten hospitals in southwest France took part in this study. Water samples were collected from 106 hot water faucets, showers, hot water tanks, and cooling towers. Two analyses were performed to analyze the association between water characteristics and (1) the presence of Legionella species and (2) the proliferation of Legionella species. Of the 106 water samples examined, 67 (63.2%) were positive for Legionella species. Amoebae were detected in 73 of 106 (68.9%) samples and in 56 of 67 (86.6%) Legionella species-positive samples (P < 10(-6)). In these positive samples, conductivity was lower than 500 microOmega(-1).cm(-1) in 58.2% (P = .026), temperature was below 50 degrees C in 80.6% (P = .004), and hardness was significantly higher (P = 002) than in Legionella species-negative samples. Neither Legionella species nor amoebae were isolated from any sampling point in which the water temperature was above 58.8 degrees C. Multivariate analysis shows that high hardness and presence of amoebae were strongly correlated statistically with the presence of Legionella when showers, tanks, pH, and temperature promoted their proliferation. This study shows the importance of water quality evaluation in assessing environmental risk factors and in selecting the most appropriate prevention and control measures in hospital water systems.
医院获得性军团病的源头已被证实是饮用水分配系统。本研究的目的如下：（1）研究水温、pH值、硬度、电导率和余氯等水的物理化学特性与作为嗜肺军团菌生长促进因子的阿米巴原虫的存在之间的可能关系；（2）确定供水系统的根除措施，以寻求降低军团病风险的方法。法国西南部的十家医院参与了这项研究。从106个热水龙头、淋浴喷头、热水箱和冷却塔采集了水样。进行了两项分析，以分析水的特性与（1）嗜肺军团菌的存在和（2）嗜肺军团菌的增殖之间的关联。在检测的106份水样中，67份（63.2%）嗜肺军团菌呈阳性。在106份（68.9%）样本中的73份以及67份嗜肺军团菌阳性样本中的56份（86.6%）检测到了阿米巴原虫（P<10⁻⁶）。在这些阳性样本中，58.2%的电导率低于500微欧·厘米⁻¹（P = 0.026），80.6%的温度低于50℃（P = 0.004），硬度显著高于嗜肺军团菌阴性样本（P = 0.002）。在水温高于58.8℃的任何采样点均未分离出嗜肺军团菌和阿米巴原虫。多变量分析表明，当淋浴喷头、水箱、pH值和温度促进其增殖时，高硬度和阿米巴原虫的存在与嗜肺军团菌的存在在统计学上密切相关。本研究表明了水质评估在评估医院水系统环境风险因素以及选择最合适的预防和控制措施方面的重要性。
