Evaluation of the Pseudalert/Quanti-Tray MPN Test for the Rapid Enumeration of Pseudomonas aeruginosa in Swimming Pool and Spa Pool Waters.
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.
SWM Consulting, 7 Sunnybank, Little Ness, Shrewsbury, SY4 2LQ, UK. david.sartory@tesco.net.
David P
DP
Sartory
IDEXX Laboratories, Newmarket Business Park, Studlands Park Avenue, Newmarket, CB8 7ER, UK.
Megan
M
Brewer
IDEXX Laboratories, Newmarket Business Park, Studlands Park Avenue, Newmarket, CB8 7ER, UK.
Agnieszka
A
Beswick
IDEXX Laboratories, Newmarket Business Park, Studlands Park Avenue, Newmarket, CB8 7ER, UK.
Darron
D
Steggles
D058491:Bacterial Load / Q000379:methods*; D045482:Hot Springs; D011550:Pseudomonas aeruginosa / Q000302:isolation & purification*; D013551:Swimming Pools; D014871:Water Microbiology