Impact of Environmental Factors on Legionella Populations in Drinking Water
Impact of Environmental Factors on Legionella Populations in Drinking Water
复制标题
环境因素对饮用水中军团菌种群的影响
作者：
D. O. Schwake;A. Alum;M. Abbaszadegan
为了考察环境因素对饮用水管网中军团菌的影响，研究了不同条件下军团菌的生长和存活情况。当在4°C、25°C和32°C的自来水中培养时，嗜肺乳杆菌的存活趋势随着温度的不同而不同，在25°C和32°C下保持稳定的种群数月表明，在这些温度下，低营养条件下可以长时间存活。在接种了聚氯乙烯、铜、黄铜和铸铁的试片后，嗜肺乳杆菌在几天内对每个试片上形成的生物膜进行了类似程度的定植，但铸铁在90天后含有少1对数的军团菌。嗜肺乳杆菌在一个模型饮用水分配系统中激增，在几天内就在该系统中定居。系统的氯化对与生物膜相关的军团菌浓度有更大的影响，种群在六周内恢复到氯化前的水平。从亚利桑那州中部两个地区采集的饮用水水表上采集的生物膜通过聚合酶链式反应(PCR)分析军团菌的存在。仅在一个地区发生的情况表明，供水系统的环境差异可能会对军团菌的生存产生影响。这些结果证明了不同环境条件对军团菌在水中生存的影响。
To examine the impact of environmental factors on Legionella in drinking water distribution systems, the growth and survival of Legionella under various conditions was studied. When incubated in tap water at 4 °C, 25 °C, and 32 °C, L. pneumophila survival trends varied amongst the temperatures, with the stable populations maintained for months at 25 °C and 32 °C demonstrating that survival is possible at these temperatures for extended periods in oligotrophic conditions. After inoculating coupons of PVC, copper, brass, and cast iron, L. pneumophila colonized biofilms formed on each within days to a similar extent, with the exception of cast iron, which contained 1-log less Legionella after 90 days. L. pneumophila spiked in a model drinking water distribution system colonized the system within days. Chlorination of the system had a greater effect on biofilm-associated Legionella concentrations, with populations returning to pre-chlorination levels within six weeks. Biofilms sampled from drinking water meters collected from two areas within central Arizona were analyzed via PCR for the presence of Legionella. Occurrence in only one area indicates that environmental differences in water distribution systems may have an impact on the survival of Legionella. These results document the impact of different environmental conditions on the survival of Legionella in water.