Validation and in-field testing of a new on-site qPCR system for quantification of Legionella pneumophila according to ISO/TS 12869:2012 in HVAC cooling towers
| Autor: | Shaimaa Ahmed, Danielle E. Walker, Alan Mears, Urszula Liwak-Muir, Agnes Zoldowski, Steve Mohr, Sergey Golovan, Chris Harder, Paul Lem |
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| Rok vydání: | 2019 |
| Předmět: |
Microbiology (medical)
Colony Count Microbial Legionella 010501 environmental sciences Real-Time Polymerase Chain Reaction 01 natural sciences Turnaround time Legionella pneumophila Sensitivity and Specificity Whole systems 03 medical and health sciences HVAC Air Conditioning Waste Management and Disposal 0105 earth and related environmental sciences Water Science and Technology 0303 health sciences International standards organization biology 030306 microbiology business.industry Public Health Environmental and Occupational Health Laboratory results biology.organism_classification Reliability engineering Infectious Diseases Environmental science Sample collection business Water Microbiology |
| Zdroj: | Journal of water and health. 17(2) |
| ISSN: | 1477-8920 |
| Popis: | Legionella pneumophila, found in engineered water systems such as HVAC cooling towers, poses a significant public health risk. Culture, though routinely used to quantify L. pneumophila, has several disadvantages including long turnaround time, low sensitivity, and inter-laboratory variability. In this study, we validated the performance of an on-site quantitative polymerase chain reaction (qPCR) detection system for L. pneumophila in accordance with International Standards Organization Technical Specification 12869:2012. We evaluated specificity, limit of detection and quantification, and calibration curve linearity. Additionally, we evaluated whole system recovery and robustness using samples taken from taps and evaporative cooling towers. We then compared the system's performance against laboratory culture and laboratory qPCR across 53 cooling towers in a 12-week in-field study. We found that concordance between on-site qPCR and culture was both laboratory- and site/sample-dependent. Comparison of laboratory qPCR with on-site qPCR revealed that laboratory results were highly variable and showed little concordance. Some discordance may be explained by time delay between sample collection and testing (‘shipping effect’) which may lead to inaccurate reporting. Overall, our study highlights the value of on-site qPCR detection of L. pneumophila, demonstrates that laboratories are prone to misreporting results due to shipping effects, and reveals significant discordance between laboratory qPCR and culture. This article has been made Open Access thanks to the generous support of a global network of libraries as part of the Knowledge Unlatched Select initiative. |
| Databáze: | OpenAIRE |
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