Comparison of the Pseudalert™/Quanti‐Tray® MPN test for the enumeration of Pseudomonas aeruginosa in cooling tower water with the ISO 16266 membrane filtration culture‐based method

AIMS: The purpose of this study was to evaluate the ISO 16266 membrane filtration culture-based method for the detection of Pseudomonas aeruginosa from cooling tower and related water samples and to compare the performance of the Pseudalert MPN method (Pseudalert/Quanti-Tray((R)) ) for the enumeration of P. aeruginosa with the ISO method. METHODS AND RESULTS: Samples were analysed by both methods and the generated data were analysed according to ISO 17994 and showed that Pseudalert resulted in significantly higher counts and a better recovery of P. aeruginosa than the ISO method for 10 and 100 ml sample volumes. CONCLUSIONS: Pseudalert represents a significant improvement in the enumeration of P. aeruginosa from cooling tower water and related samples. The advantages of Pseudalert became apparent in a better performance, a more than 10-fold higher upper quantification limit when using Quanti-Tray/2000 and a shorter incubation time with no requirement for further confirmation, resulting in a faster reporting of results. SIGNIFICANCE AND IMPACT OF THE STUDY: The (Pseudalert/Quanti-Tray) MPN method offers a more efficient and sensitive test for enumerating P. aeruginosa from cooling tower waters, thus significantly improving management of occupational safety during cleaning and maintenance activities of cooling towers.