Evaluation of the Pseudalert®/Quanti-Tray® MPN Test for the Rapid Enumeration of Pseudomonas aeruginosa in Swimming Pool and Spa Pool Waters

• Published in: Current microbiology Vol. 71; no. 6; pp. 699 - 705
• Main Authors: Sartory, David P., Brewer, Megan, Beswick, Agnieszka, Steggles, Darron
• Format: Journal Article
• Language: English
• Published: New York Springer US 01.12.2015
• Subjects: Bacterial Load - methods; Biomedical and Life Sciences; Biotechnology; Hot Springs; Life Sciences; Microbiology; Original Research; Pseudomonas aeruginosa - isolation & purification; Swimming Pools; Water Microbiology; International Standard Organisation; Much Probable Number; Otitis Externa; Swimming Pool; Pool Water
• ISSN: 0343-8651; 1432-0991
• DOI: 10.1007/s00284-015-0905-8

This study assessed the performance of a new most probable number test (Pseudalert ® /Quanti-Tray ® ) for the enumeration of Pseudomonas aeruginosa from swimming pool and spa pool waters by comparing it to the international and national membrane filtration-based culture methods for P. aeruginosa : ISO 16266:2006 and UK The Microbiology of Drinking Water — Part 8 (MoDW Part 8) which both use Pseudomonas CN agar. The comparison was based on the calculation of mean relative differences between the two methods conducted according to ISO 17994:2014. Using both routine pool water samples (149 from 8 laboratories) and artificially contaminated samples (309 from 7 laboratories), paired counts from each sample and enumeration method were analysed. For routine samples, there were insufficient data for a conclusive assessment, but the data do indicate at least equivalent performance of Pseudalert ® /Quanti-Tray ® to the reference methods. For the artificially contaminated samples, the data also did not result in a statistically conclusive assessment but did indicate potentially better performance of Pseudalert ® /Quanti-Tray ® . Combining the data from the routine samples and artificially contaminated samples resulted in an ISO 17994 outcome that the two methods were not statistically significantly different. Thus, the Pseudalert ® /Quanti-Tray ® method is an acceptable alternative to ISO 16266 and MoDW Part 8. The Pseudalert ® /Quanti-Tray ® method has the advantage in that it does not require confirmation testing, and of providing confirmed counts within 24–28 h incubation compared to 40–48 h or longer for the ISO 16266 and MoDW Part 8 methods.