Simple Detection of Culturable Legionella pneumophila in Cooling Tower Water Samples using Legiolert
Year: 2025
Type: article
Abstract: The control of Legionella contamination in artificial water e n v i ro n m e n t s i s i m p o r t a n t f o r t h e p re v e n t i o n o f Legionnaires disease.In Japan, Legionella populations in cooling tower waters must be kept below 100 colonyforming units (CFU) /100 mL according to the Guideline for Prevention of Legionnaires Disease (Tateda et al., 2024) .The plate culture method is widely used for monitoring Legionella, but this method is complicated and timeconsuming.Legiolert (IDEXX Laboratories, Inc., Westbrook, Maine, USA) can specifically detect Legionella pneumophila using a specific enzyme-substrate medium.In contrast to the plate culture method, Legiolert is simple to use and positive correlations with the results of the plate culture method have been demonstrated for cooling tower water (Petrisek and Hall, 2018;Rech et al., 2018;Barrette, 2019) and potable water (Sartory et al., 2017;Spies et al., 2018;Petrisek and Hall, 2018;Scaturro et al., 2020;Boczek et al., 2021) .In a previous report, agreement between the results of Legionella spp.detection by the plate culture method and the results of L. pneumophila detection by Legiolert in bath water samples was 83.3% (Inoue et al. 2020) .In this study, we tested cooling tower water samples obtained throughout Japan for L. pneumophila using both Legiolert and the conventional plate culture method.The results generated in seven laboratories belonging to the Japan Association of Anti-Legionella Chemicals for Cooling Water were evaluated.Water samples were collected from cooling towers located in factories, commercial buildings and hospitals across Japan.The presence of L. pneumophila was detected using the Legiolert and plate culture methods.Legiolert was evaluated using 1 mL of non-potable water (Legiolert-1 mL) and 10 mL of non-potable water (Legiolert-10 mL) .The sensitivity of Legiolert-1 mL is sufficient for testing to the guideline value for cooling tower water (<100 CFU/100 mL) , although the more sensitive Legiolert-10 mL was also evaluated for comparison.Water samples were tested using Legiolert according to the protocols specified by IDEXX Laboratories, Inc. Briefly, in the Legiolert-1 mL test, 2 mL of pretreatment reagent (Legiolert Pretreatment, IDEXX) was added to 2 mL of cooling tower water.After incubation at room temperature for 1 min, 2 mL of the treated sample was added to 100 mL of Legiolert liquid medium (one package of Legiolert powder dissolved in 100 mL of sterile water) .In the Legiolert-10 mL test, 0.5 mL of concentrated pretreatment reagent (20× Legiolert Pretreatment, IDEXX) was added to 10 mL of Note
Source: Journal of Microorganism Control
DOI: 10.4265/jmc.30.3_99
Authors: HIROAKI INOUE, MASAKI OKAMOTO, MIYUKI KATADA, TATSUYUKI KANEKO, MASATO SENSUI, HIROAKI NAKATA, HIRONORI HATTORI
Language: English
Subfield: Endocrinology
Domain: Life Sciences
Open Access status: bronze
OpenAlex ID: W4414600050
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