The opportunistic, waterborne pathogen Legionella caused 9,933 cases of Legionnaires' disease in 2018 in the United States (CDC.gov). The incidence of Legionnaires' disease can be reduced by maintaining clean building water systems through water management programs (WMPs). WMPs often include validation testing to confirm the control of bacteria, but the traditional culture method for enumerating Legionella requires 10–14 days to obtain results. A rapid DNA extraction developed by Phigenics and a real-time PCR negative screen for the genus Legionella provided results the day after sampling. This study evaluated the Next Day Legionella PCR (Phigenics, LLC) compared with the traditional culture method (ISO 11731) on 11,125 building water samples for approximately 1 year. Two DNA extraction methods (Methods 1 and 2) were compared. The negative predictive value (NPV) of the Next Day Legionella PCR in comparison to traditional culture for Method 1 was 99.95%, 99.92%, 99.85%, and 99.17% at >10, >2, >1, and >0.1 CFU/ml limits of detection, respectively. The improved DNA extraction (Method 2) increased the NPV to 100% and 99.88% at >1 and >0.1 CFU/ml, respectively. These results demonstrate the reliability of the genus-level Legionella PCR negative screen to predict culture-negative water samples.

机会性水生病原菌退伍军人病菌于2018年在美国引起了9,933例退伍军人病病例（CDC.gov）。通过水管理计划（WMP）维护清洁的建筑水系统，可以减少军团病的发生。WMP通常包括验证测试以确认细菌的控制，但是用于计数军团菌的传统培养方法需要10到14天才能获得结果。Phigenics开发的快速DNA提取和军团菌属的实时PCR阴性筛选提供了采样后一天的结果。这项研究评估了第二天的军团菌PCR（Phigenics，LLC）与传统培养方法（ISO 11731）在11,125个建筑用水样品上进行了大约1年的比较。比较了两种DNA提取方法（方法1和2）。方法1的第二天军团菌PCR与传统培养相比的阴性预测值（NPV）在> 10，> 2，> 1和> 0.1 CFU / ml时分别为99.95％，99.92％，99.85％和99.17％检测限。改进的DNA提取（方法2）分别在> 1和> 0.1 CFU / ml时将NPV分别提高到100％和99.88％。这些结果证明了属水平军团菌PCR阴性筛查可预测培养阴性水样的可靠性。