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Future of Legionella Monitoring: Strategies for Employing qPCR in a WMP
Episode 376
"To find the most sensitive, accurate, reproducible, and reliable method for detecting and quantifying Legionella in a sample, qPCR is the best option." - Michael Loewenstein
In this much-anticipated episode highlighting the findings of Part 2 of Michael Loewenstein and Joe Benzinger's study, Michael Loewenstein, Vice President of Scientific Consulting at Q Laboratories, returns to share their surprising discoveries. He offers valuable advice to water professionals on developing strategies for incorporating qPCR in a Water Management Plan (WMP). Join Trace Blackmore and Michael Loewenstein as they guide you through the latest advancements in Legionella detection methods, the nuances of traditional culture techniques versus modern qPCR, and the future of water management.
What Are the Different Testing Methods for Legionella? Michael elaborates on the two primary methods for Legionella testing: traditional culture techniques (ISO 11731) and qPCR. Culture methods, while widely used, take a significant amount of time (7 to 14+ days) to yield results. In contrast, qPCR offers faster and more sensitive detection, identifying the presence and quantity of Legionella DNA in a matter of hours.
Is There a "Gold Standard" for Legionella Testing? The term "Gold Standard" often pops up in discussions about Legionella testing, but as Michael points out, no regulatory body has officially designated a single best method. While ISO 11731 is a trusted standard, Michael argues that qPCR provides a more reliable, accurate, and sensitive approach for detecting and quantifying Legionella in samples.
What Were the Findings from Phase 2 of His Study? Michael shares findings from a two-phase study comparing cultural methods with PCR and qPCR. Phase 1 focused on method validation, confirming the efficacy of commercially available PCR methods. Phase 2 moved to real-world samples, revealing that qPCR detected Legionella in about 67% of samples, far surpassing the detection rates of traditional culture methods.
What Can qPCR Do and How Does It Differ from Culture Methods? qPCR is a powerful tool in Legionella testing. Unlike culture methods that rely on colony-forming units, qPCR measures the number of DNA copies present in a sample, providing a clear picture of the Legionella population. It can also distinguish between viable and non-viable cells, making it a comprehensive and efficient method for routine monitoring.
How Would Michael Set Up His Water Management Plan (WMP)? When asked how he would set up his water management plan, Michael emphasizes the importance of frequent testing. He advocates for the use of qPCR due to its speed and sensitivity. However, he cautions that those uncomfortable with detecting any Legionella might find qPCR overwhelming, as it tends to reveal a higher positivity rate than traditional methods.
How Does Pricing Compare Between Culture and qPCR Methods?Interestingly, Q Laboratories charges the same for both qPCR and culture methods. Despite higher costs for qPCR, it requires significantly less analyst time, making it a cost-effective choice for many labs.
What's Next for Phase 3 of the Study? The next phase of Michael's study aims to explore additional factors such as UV light treatment. He encourages feedback from the community to ensure all relevant aspects are covered in the ongoing research.
How Can I Get Involved with the AOAC Legionella Working Group? Please visit www.aoac.
Published on 1 year, 4 months ago