The Enterolert-DW Test uses a Defined Substrate Technology (DST) nutrient indicator to detect enterococci. When coupled with the IDEXX Quanti-Tray System, the Enterolert-DW Test provides quantitative confirmed results in 24 hours. The Enterolert-DW Test utilizes ortho-nitrophenyl-β-D-glucoside as a nutrient indicator and incorporates a specifically designed blue background color in its formulation. When the enzyme substrate is metabolized by enterococci, the sample turns from blue to green to indicate detection. Any change from the original color to green is considered a positive result. No ultraviolet light source is required.
Add reagent to sample. Cap vessel and shake to mix.
Seal using Quanti-Tray Sealer and incubate for 24 hours at 41°C ± 0.5°C.
Count positive wells and refer to most probable number (MPN) table.
How does the product work?
The Enterolert-DW Test is designed to detect Enterococcus species in drinking water samples. It is based on IDEXX’s proprietary Defined Substrate Technology (DST). The Enterolert-DW Test utilizes ortho-nitrophenyl-ß-D-glucoside as a nutrient indicator and incorporates a specifically designed blue background color in its formulation. When the enzyme substrate is metabolized by the enterococci, the sample turns from blue to green to indicate a positive detection. Any change from the original color to green is considered a positive result. No ultraviolet light source is required.
What species of enterococci can the Enterolert-DW test detect?
The Enterolert-DW Test is designed to detect enterococci in drinking water. As with any microbial method, some Enterococcus species are more easily detected than others. Some examples of Enterococcus species we have detected in trials and studies are:
Is there a comparator for the Enterolert-DW Test?
There is no comparator for the Enterolert-DW Test. For comparison, use a negative control when interpreting results.
What is the incubation time and temperature of the Enterolert-DW Test?
The Enterolert-DW Test is incubated at 41°C ± 0.5°C for 24 hours and the results are valid up to 28 hours, unless your local regulations indicate differently.
Are results valid prior to 24 hours?
Yes, if they are positive. An inoculated Enterolert-DW Test sample that is positive for enterococci before 24 hours is a confirmed positive test for enterococci.
Are results valid after 28 hours?
Yes, if they are negative. If an inoculated Enterolert-DW Test sample is inadvertently incubated over 28 hours, lack of green color is a valid negative test; a green color after the 28 hours is not valid and should be repeated or verified.
Can either the 51-well or the 97-well Quanti-Tray be used with the Enterolert-DW Test?
Yes, both the Quanti-Tray and Quanti-Tray/2000 can be used with the Enterolert-DW Test.
Which vessels should I use with the Enterolert-DW Test?
Because the Enterolert-DW Test is used with the Quanti-Tray system, any sterile vessel can be used.
What are the recommended storage conditions for the Enterolert-DW Test?
Store the Enterolert-DW Test at 2–25°C, away from direct light and humidity.
What normal color change should take place with the Enterolert-DW Test?
When the enzyme substrate is metabolized by the enterococci, the sample turns from blue to green to indicate a positive result. Any change from the original color to green is considered a positive result.
What water types can the product be used on/what water type is the product designed to be used for?
The Enterolert-DW Test is designed specifically for drinking water testing. Extensive studies were performed on enterococci stressed by chlorine, to mimic the impact of water treatment.
Can the Enterolert-DW Test be used on water types other than drinking water?
The Enterolert-DW Test may be used for other water types. Before implementing testing, IDEXX recommends you use a typical laboratory validation protocol to assure that any other water types will work with this product before implementation.
What color and consistency should the the Enterolert-DW reagent powder be?
The Enterolert-DW reagent powder should be white to off-white in color with a slight greenish tint; it should be dry and free-flowing. Any concerns about the color or integrity of the reagent powder should be directed to IDEXX Technical Support.
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.
Enterolert-DW Test (20-test pack)
Catalog Number: WENTDW-020
Enterolert-DW Test (200-test pack)
Catalog Number: WENTDW-200
Snap pack and Quanti-Tray bundles are available.