Enterolert 250

The Enterolert 250 Test is designed to detect Enterococcus species in bottled water samples. It is based on IDEXX’s proprietary Defined Substrate Technology (DST). The Enterolert 250 Test utilizes ortho-nitrophenyl-ß-D-glucoside as a nutrient indicator and incorporates a specifically designed blue background colour in its formulation. When the enzyme substrate is metabolised by the enterococci, the sample turns from blue to green to indicate a positive detection. Any change from the original colour to green is considered a positive result. No ultraviolet light source is required. The Enterolert 250 Test detects enterococci at 1 cfu in 250 mL bottled water samples in 24 hours.

The Enterolert 250 Test is designed to detect enterococci in bottled 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:
Enterococcus faecalis
Enterococcus faecium
Enterococcus hirae
Enterococcus gallinarum
Enterococcus casseliflavus
Enterococcus durans
Enterococcus avium

There is no comparator for the Enterolert 250 Test. For comparison, use a negative control when interpreting results.

The Enterolert 250 Test is incubated at 41°C ± 1.0°C for 24 hours and the results are valid up to 28 hours, unless your local regulations indicate differently.

Yes, if the results are positive. An inoculated Enterolert 250 Test sample that is positive for enterococci before 24 hours is a confirmed positive test for enterococci.

Yes, if the results are negative. If an inoculated Enterolert 250 Test sample is inadvertently incubated over 28 hours, lack of green color is a valid negative test; a green colour after the 28 hours is not valid and should be repeated or verified.

Store the Enterolert 250 Test at 2–25°C, away from direct light and humidity.

When the enzyme substrate is metabolised by the enterococci, the sample turns from blue to green to indicate a positive result. Any change from the original colour to green is considered a positive result.

The Enterolert 250 Test is designed specifically for bottled water testing.

The Enterolert 250 reagent powder should be white to off-white in colour with a slight greenish tint; it should be dry and free-flowing. Any concerns about the colour or integrity of the reagent powder should be directed to IDEXX Technical Support.