Legiolert

For detection of Legionella pneumophila

   

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

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Overview

Easy
  • Any brown color and/or turbidity indicates a positive for Legionella pneumophila.
  • Platform similar to that of the Colilert 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 color and/or turbidity indicates a positive and minimizes 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 utilization 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

Learn how to use the Legiolert test

File Icon  View/Print Legiolert Test Procedure

Learn how to use Legiolert
View a tutorial on how to use the Legiolert Test
 

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

Potable Samples

The following instructions are for use with potable water samples in North America only.

Step 1


Prepare 1:10 dilution of potable water sample in sterile diluent.

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.

 
Nonpotable Samples

The following instructions are for use with nonpotable water samples in North America only.

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 specifically 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 utilization 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.

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 protocol for potable water, the Legiolert test detects Legionella pneumophila at ≥10 organisms/100mL. When using the protocol for nonpotable water, the Legiolert test detects Legionella pneumophila at ≥10 organisms/mL (≥1000 organism/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 color and turbidity is a valid negative test result. However, brown color 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 and nonpotable protocols?

If you are unsure whether your water is potable or nonpotable, please contact IDEXX Technical Services at 1-800-321-0207 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 color and consistency should the Legiolert reagent powder be?
The Legiolert reagent powder should be very light to light tan in color and free-flowing. If you have any concerns about the color or integrity of the powder, contact IDEXX Technical Services at 1-800-321-0207.

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, state, and/or federal authorities for proper disposal of bacteriological biohazard materials at your facility.

Is the Legiolert test U.S. EPA approved?
The Legiolert test is not U.S. EPA approved for testing for Legionella pneumophila in potable or nonpotable water. Legionella pneumophila water testing is not federally regulated in the United States. Testing for Legionella pneumophila in potable or nonpotable water may or may not be mandated by local and/or state authorities. Please check for regulations that may apply in your area.

Is the Legiolert test in Standard Methods for the Examination of Water and Wastewater?
The Legiolert test is not currently included in Standard Methods. IDEXX will pursue a listing for this test, as appropriate.

What are the plans for gaining regulatory approval of the Legiolert test ?
IDEXX plans to conduct regulatory trials in countries where Legionella pneumophila is regulated for potable and/or nonpotable water. 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) and Legionella anisa ATCC 35292 (WDCM 00106) are recommended negative control strains.

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 and nonpotable protocols have each been designed for optimal performance with different types of 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 pretreatment step and smaller volume of sample tested.

Why is the Legiolert Pretreatment 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 optimized 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. Find the document(s) you need by selecting the link below.


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Product information

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

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

Legiolert Pretreatment
Catalog Number: WLGT-PRE

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

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

IDEXX-QC Legionella
Catalog Number: UN3373-WQC-LGT

IDEXX Water Customer Support

Corporate Headquarters
IDEXX Laboratories, Inc.
One IDEXX Drive
Westbrook, Maine 04092 USA

Tel: 1-800-321-0207
Fax: 1-207-556-4630

Find a representative near you.

ISO Certifications

File Icon  ISO 9001:2008

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