PCR-Based <i>Legionella</i> Risk Evaluation of Drinking Water Systems—An Empirical Field Evaluation

Pathogens in water systems pose potential health risks. Several countries provide guidelines and risk management strategies for clean water systems. Regarding legionellae, culture-based methods are still the gold standard, whereas molecular methods such as quantitative real-time PCR (qPCR) are contr...

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Main Authors: Markus Petzold, Nicole Zacharias, Sarah Uhle, Laurine Kieper, Nico Tom Mutters, Thomas Kistemann, Christiane Schreiber
Format: Article
Language:English
Published: MDPI AG 2025-06-01
Series:Microorganisms
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Online Access:https://www.mdpi.com/2076-2607/13/6/1311
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author Markus Petzold
Nicole Zacharias
Sarah Uhle
Laurine Kieper
Nico Tom Mutters
Thomas Kistemann
Christiane Schreiber
author_facet Markus Petzold
Nicole Zacharias
Sarah Uhle
Laurine Kieper
Nico Tom Mutters
Thomas Kistemann
Christiane Schreiber
author_sort Markus Petzold
collection DOAJ
description Pathogens in water systems pose potential health risks. Several countries provide guidelines and risk management strategies for clean water systems. Regarding legionellae, culture-based methods are still the gold standard, whereas molecular methods such as quantitative real-time PCR (qPCR) are controversially discussed among experts as an alternative. It remains questionable as to whether monitoring by qPCR contributes to sustainable water hygiene and effective health prevention. Drinking water samples from 101 buildings were culture-based analyzed to determine the legionellae concentration, along with qPCR tests. The negative predictive values for <i>Legionella</i> spp. and <i>L. pneumophila</i> qPCR regarding the cultivation method were 100% and 98%, respectively. As <i>Legionella</i> spp. DNA is ubiquitously detected, the positive predictive value was low. <i>L. pneumophila</i> DNA was in 18% of the drinking water samples detected by qPCR, among which only 7% was quantifiable. Neither gold-standard methods of cultivation nor qPCR methods alone are suitable to monitor the risk to health by legionellae in water environments adequately. To overcome methodical difficulties, the benefits of a strategic integration of qPCR alongside cultivation methods should be applied to develop a comprehensive protocol for the stepwise analysis of water samples, which can be implemented in international regulatory frameworks in the future.
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institution Kabale University
issn 2076-2607
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publishDate 2025-06-01
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spelling doaj-art-e5b19ffa73e24cba806666ba9ac91ea82025-08-20T03:27:40ZengMDPI AGMicroorganisms2076-26072025-06-01136131110.3390/microorganisms13061311PCR-Based <i>Legionella</i> Risk Evaluation of Drinking Water Systems—An Empirical Field EvaluationMarkus Petzold0Nicole Zacharias1Sarah Uhle2Laurine Kieper3Nico Tom Mutters4Thomas Kistemann5Christiane Schreiber6Institute of Medical Microbiology and Virology, University Hospital Dresden, Dresden University of Technology, Fetscherstraße 74, 01307 Dresden, GermanyInstitute for Hygiene and Public Health, University Hospital Bonn, Venusberg-Campus 1, 53127 Bonn, GermanyInstitute of Medical Microbiology and Virology, University Hospital Dresden, Dresden University of Technology, Fetscherstraße 74, 01307 Dresden, GermanyInstitute of Medical Microbiology and Virology, University Hospital Dresden, Dresden University of Technology, Fetscherstraße 74, 01307 Dresden, GermanyInstitute for Hygiene and Public Health, University Hospital Bonn, Venusberg-Campus 1, 53127 Bonn, GermanyInstitute for Hygiene and Public Health, University Hospital Bonn, Venusberg-Campus 1, 53127 Bonn, GermanyInstitute for Hygiene and Public Health, University Hospital Bonn, Venusberg-Campus 1, 53127 Bonn, GermanyPathogens in water systems pose potential health risks. Several countries provide guidelines and risk management strategies for clean water systems. Regarding legionellae, culture-based methods are still the gold standard, whereas molecular methods such as quantitative real-time PCR (qPCR) are controversially discussed among experts as an alternative. It remains questionable as to whether monitoring by qPCR contributes to sustainable water hygiene and effective health prevention. Drinking water samples from 101 buildings were culture-based analyzed to determine the legionellae concentration, along with qPCR tests. The negative predictive values for <i>Legionella</i> spp. and <i>L. pneumophila</i> qPCR regarding the cultivation method were 100% and 98%, respectively. As <i>Legionella</i> spp. DNA is ubiquitously detected, the positive predictive value was low. <i>L. pneumophila</i> DNA was in 18% of the drinking water samples detected by qPCR, among which only 7% was quantifiable. Neither gold-standard methods of cultivation nor qPCR methods alone are suitable to monitor the risk to health by legionellae in water environments adequately. To overcome methodical difficulties, the benefits of a strategic integration of qPCR alongside cultivation methods should be applied to develop a comprehensive protocol for the stepwise analysis of water samples, which can be implemented in international regulatory frameworks in the future.https://www.mdpi.com/2076-2607/13/6/1311<i>Legionella</i>qPCRculturemonitoringdrinking waterhygiene
spellingShingle Markus Petzold
Nicole Zacharias
Sarah Uhle
Laurine Kieper
Nico Tom Mutters
Thomas Kistemann
Christiane Schreiber
PCR-Based <i>Legionella</i> Risk Evaluation of Drinking Water Systems—An Empirical Field Evaluation
Microorganisms
<i>Legionella</i>
qPCR
culture
monitoring
drinking water
hygiene
title PCR-Based <i>Legionella</i> Risk Evaluation of Drinking Water Systems—An Empirical Field Evaluation
title_full PCR-Based <i>Legionella</i> Risk Evaluation of Drinking Water Systems—An Empirical Field Evaluation
title_fullStr PCR-Based <i>Legionella</i> Risk Evaluation of Drinking Water Systems—An Empirical Field Evaluation
title_full_unstemmed PCR-Based <i>Legionella</i> Risk Evaluation of Drinking Water Systems—An Empirical Field Evaluation
title_short PCR-Based <i>Legionella</i> Risk Evaluation of Drinking Water Systems—An Empirical Field Evaluation
title_sort pcr based i legionella i risk evaluation of drinking water systems an empirical field evaluation
topic <i>Legionella</i>
qPCR
culture
monitoring
drinking water
hygiene
url https://www.mdpi.com/2076-2607/13/6/1311
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