EDF Research and Development, Laboratoire National d'Hydraulique et d'Environnement, Chatou Cedex, France.
J Appl Microbiol. 2011 Aug;111(2):499-510. doi: 10.1111/j.1365-2672.2011.05063.x. Epub 2011 Jun 23.
This study was designed to evaluate the usefulness of quantification by real-time PCR as a management tool to monitor concentrations of Legionella spp. and Legionella pneumophila in industrial cooling systems and its ability to anticipate culture trends by the French standard method (AFNOR T90-431).
Quantifications of Legionella bacteria were achieved by both methods on samples from nine cooling systems with different water qualities. Proportion of positive samples for L. pneumophila quantified by PCR was clearly lower in deionized or river waters submitted to a biocide treatment than in raw river waters, while positive samples for Legionella spp. were quantified for almost all the samples. For some samples containing PCR inhibitors, high quantification limits (up to 4·80 × 10(5) GU l(-1) ) did not allow us to quantify L. pneumophila, when they were quantified by culture. Finally, the monitoring of concentrations of L. pneumophila by both methods showed similar trends for 57-100% of the samples.
These results suggest that, if some methodological steps designed to reduce inhibitory problems and thus decrease the quantification limits, could be developed to quantify Legionella in complex waters, the real-time PCR could be a valuable complementary tool to monitor the evolution of L. pneumophila concentrations.
This study shows the possibility of using real-time PCR to monitor L. pneumophila proliferations in cooling systems and the importance to adapt nucleic acid extraction and purification protocols to raw waters.
本研究旨在评估实时 PCR 定量作为监测工业冷却系统中军团菌属和嗜肺军团菌浓度的管理工具的有用性，以及其通过法国标准方法（AFNOR T90-431）预测培养趋势的能力。
通过两种方法对来自 9 个具有不同水质的冷却系统的样品进行了军团菌定量。与未经处理的河水相比，经去离子或河水处理的样品中定量 PCR 检测到的嗜肺军团菌阳性样本比例明显较低，而定量 PCR 检测到的军团菌属阳性样本几乎涵盖了所有样品。对于一些含有 PCR 抑制剂的样品，由于定量极限较高（高达 4.80×10^5GU l^-1），当通过培养进行定量时，无法定量检测到嗜肺军团菌。最后，两种方法监测的嗜肺军团菌浓度在 57%-100%的样品中显示出相似的趋势。
这些结果表明，如果可以开发出一些旨在减少抑制问题的方法步骤，从而降低定量极限，实时 PCR 可以成为监测嗜肺军团菌浓度变化的有价值的补充工具。
本研究表明了使用实时 PCR 监测冷却系统中嗜肺军团菌增殖的可能性，以及对原始水适应核酸提取和纯化方案的重要性。
