Legiolert

For detection of Legionella pneumophila

    

  • Detects Legionella pneumophila up to 7 days faster than traditional culture methods.
  • Easy-to-use platform, similar to that of the Colilert Test.
  • Easy test setup significantly reduces laboratory work flow.
  • Delivers definitive results in 7 days without additional confirmation steps.
  • Reduces quality control (QC) steps.

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Overview

Easy
  • Any brown colour and/or turbidity indicates a positive for Legionella pneumophila.
  • Platform similar to that of the Colilert-18 Test: Ready-to-use reagents, no media preparation.
  • Use with Quanti-Tray/Legiolert for Most Probable Number (MPN) enumeration.

Rapid
  • Confirmed results in 7 days without additional steps.
  • Streamlined work flow with less than 2 minutes of hands-on time.
  • Quality control procedure can be done in 15 minutes.
Accurate
  • Specifically detects Legionella pneumophila, the primary cause of Legionnaires’ disease.1
  • Any brown colour and/or turbidity indicates a positive and minimises subjective result interpretation.

Science

How the Legiolert Test works

The Legiolert test detects Legionella pneumophila in water samples. This test is based on a bacterial enzyme detection technology that signals the presence of Legionella pneumophila through utilisation of a substrate present in the Legiolert reagent. Legionella pneumophila cells grow rapidly and reproduce using the rich supply of amino acids, vitamins, and other nutrients present in the Legiolert reagent. Actively growing strains of Legionella pneumophila use the added substrate to produce a brown color indicator. The Legiolert test detects Legionella pneumophila at 1 organism in 100 mL within 7 days.

How to Use

How to use the Legiolert test

File Icon  View/Print Legiolert Test Procedure

 
 
 

Potable

 
 
 

Nonpotable

 

A step-by-step guide to using the Legiolert test

Potable Samples:

100 ml protocol

Step 1


Measure hardness of potable water sample and add corresponding Legiolert supplement.

Step 2


Add reagent to water sample and shake to dissolve.

Step 3


Pour sample into Quanti-Tray/Legiolert.

Step 4


Seal using the Quanti-Tray Sealer PLUS and incubate for 7 days.

Step 5


Read results: Any brown and/or turbid wells are positive for Legionella pneumophila.

Quanti-Tray/Legiolert provides Most Probable Number (MPN) results up to 2,272 per 100 mL sample.

View/Print Quanti-Tray/Legiolert Insert and Most Probable Number Table.

 
Nonpotable Samples

The following instructions are for use with nonpotable water samples.

Step 1


Add reagent to sterile diluent.

Step 2


Treat nonpotable sample with Legiolert pretreatment.

Step 3


Add pretreated sample to reagent mixture.

Step 4


Pour sample into Quanti-Tray/Legiolert.

Step 5


Seal using the Quanti-Tray Sealer PLUS and incubate for 7 days.

Step 6


Read results: Any brown and/or turbid wells are positive for Legionella pneumophila.

Quanti-Tray/Legiolert provides Most Probable Number (MPN) results up to 2,272 per 100 mL sample.

 

Q & A

Frequently asked questions and answers

What water types can be tested with the Legiolert test?
The Legiolert test is designed for potable and nonpotable water samples.

How does the Legiolert test work?
The Legiolert test detects Legionella pneumophila in potable and nonpotable water samples. This test is based on a bacterial enzyme-detection technology that signals the presence of Legionella pneumophila through utilisation of a substrate present in the Legiolert reagent. Legionella pneumophila cells grow rapidly and reproduce using the rich supply of amino acids, vitamins, and other nutrients present in the Legiolert reagent. Actively growing strains of Legionella pneumophila use the added substrate to produce a brown colour indicator. The Legiolert test detects Legionella pneumophila at 1 organism in 100 mL within 7 days.

Why does the Legiolert test detect only Legionella pneumophila and not other Legionella species?
The Legiolert test is designed to specifically detect the primary causative agent of Legionnaires’ disease, which is Legionella pneumophila.

What is the detection limit of the Legiolert test?
When using the 100 ml protocol for potable water, the Legiolert test detects Legionella pneumophila at 1 organism/100 mL When using the 1.0 mL protocol for nonpotable water, the Legiolert test detects Legionella pneumophila at ≥ 1 organism/mL (≥ 100 organisms/100 mL.)

Is there a comparator for the Legiolert test?
There is no comparator for the Legiolert test. For comparison, use a negative control when interpreting results.

What is the incubation time and temperature for samples tested with the Legiolert test?
Potable water samples are incubated at 39°C (± 0.5°C) for 7 days. Nonpotable water samples are incubated at 37°C (± 0.5°C) for 7 days. Results can be read any time on the 7th day.

Can I incubate at a temperature other than the recommended 39°C for potable samples or 37°C for nonpotable samples?
No, false-positive results due to bacteria other than Legionella pneumophila and/or reduced Legionella pneumophila detection can occur at temperatures other than 39°C (± 0.5°C) for potable samples and 37°C (± 0.5°C) for nonpotable samples.

What level of humidity needs to be kept in order to incubate the Legiolert test?
The Legiolert test requires a humidity level that ensures ≤10% sample volume loss in the Quanti-Tray/Legiolert wells. Appropriate humidity can typically be achieved by placing a pan of water on the bottom of the incubator so that it covers approximately 80% of the bottom interior surface.

Are results valid prior to 7 days?
Yes, if the results are positive. An inoculated Legiolert test sample that is positive before 7 days is a confirmed positive test for L. pneumophila. However, for an accurate quantitative determination of L. pneumophila in a sample, the results should be read at 7 days.

Are results valid after 7 days?
Yes, if the results are negative. If an inoculated Legiolert test sample is inadvertently incubated for more than 7 days, the lack of brown colour and turbidity is a valid negative test result. However, brown colour and/or turbidity that develops after 7 days is not a valid positive test result; the test should be repeated or verified.

Can either a 51-well Quanti-Tray or a 97-well Quanti-Tray/2000 be used with the Legiolert test?
No, the Legiolert Test can only be used with Quanti-Tray/Legiolert and it must be incubated paper-side down.

If I do not know what type of water my sample is, can I test it using the potable protocol?
If you are unsure whether your water is potable or nonpotable, please contact IDEXX Technical Services at +44 (0) 1638 676800 for assistance.

What are the recommended storage conditions for the Legiolert test ?
Store the Legiolert test at 2–25°C away from light and humidity.

What colour and consistency should the Legiolert reagent powder be?
The Legiolert reagent powder should be very light to light tan in colour and free-flowing. If you have any concerns about the colour or integrity of the powder, contact IDEXX Technical Services at +44 (0) 1638 676800.

Can I use my Quanti-Tray 2x Sealer for Legiolert test samples?
No. Quanti-Tray/Legiolert is specifically designed to be used with the Quanti-Tray Sealer PLUS.

How should customers dispose of a positive Legiolert test sample?
Check with your local government authorities for proper disposal of bacteriological biohazard materials at your facility.

What are the plans for gaining regulatory approval of the Legiolert test ?
IDEXX plans to conduct regulatory trials in countries where Legionella is regulated. Please refer to our approval map for updated approvals.

Do water samples need to be at room temperature before the Legiolert test is added?

Varied sample temperatures were not validated during the Legiolert test product development. All samples tested were at room temperature before the testing began.

What organisms are recommended for quality control with the Legiolert test ?
Legionella pneumophila ATCC 33152 (WDCM 00107) or ATCC 33156 (WDCM 00180) are recommended positive control strains. Enterococcus faecalis ATCC 29212 (WDCM 00087) is a recommended negative control strain.

Can incubators sold by IDEXX be used to incubate the Legiolert test samples?
Yes, the Binder incubator sold by IDEXX Water is able to handle the higher humidity required by the Legiolert Test. Appropriate humidity can typically be achieved by placing a pan of water on the bottom of the incubator so that it covers approximately 80% of the bottom interior surface.

Do I need to know if my water sample is potable or nonpotable before I analyze it?
Yes, the Legiolert potable protocol has been designed for optimal performance with potable water. Testing a nonpotable sample with the potable protocol may provide false-positive results due to bacteria other than Legionella pneumophila. Testing a potable sample with the nonpotable protocol may result in reduced Legionella pneumophila detection due to the pre-treatment step and smaller volume of sample tested.

Why is the Legiolert Pretreament required when testing nonpotable water samples with Legiolert?
Nonpotable water may contain high concentrations of bacteria other than Legionella pneumophila. The Legiolert test nonpotable protocol and the Legiolert Pretreatment have been optimised to prevent these non-target organisms from interfering with the test result.

Test & Accessories

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Resources & Product Information

Resources

IDEXX Water has reference materials and approval documents to support the many products in our water portfolio.

Product information

Legiolert (20-test pack)
Catalogue Number: WLGT-20

Legiolert (100-test pack)
Catalogue Number: WLGT-100

Legiolert Supplement
Catalogue Number: WLGT-SUP

Legiolert Pretreatment
Catalogue Number: WLGT-PRE

Quanti-Tray/Legiolert (20 pack)
Catalogue Number: WQTLGT-20

Quanti-Tray/Legiolert (100 pack)
Catalogue Number: WQTLGT-100

IDEXX-QC Legionella pneumophila
Catalogue Number: UN3373-WQC-LP

IDEXX Water Customer Support

UK Headquarters

IDEXX Technologies Ltd Units 1B & 1C, Newmarket Business Park, Studlands Park Avenue, Newmarket, Suffolk, CB87ER

Tel: 01638 676800

Wateruk@idexx.com

ISO Certifications

File Icon  ISO 9001:2008

File Icon  ISO 17025:2005

File Icon  ISO 14001:2004

Reference
  1. Brunette GW, ed. CDC Health Information for International Travel 2016: The Yellow Book. New York, NY: Oxford University Press; 2016.