Snap Stick Qualitative Reference Cultures from NSI Lab Solutions


IDEXX Enterolert-DW

Principle: Uses a Defined Substrate Technology (DST) nutrient indicator

Automation: No

Approvals: AFNOR NF Validation (IDX 33/03-10/13)

Suitability: Enumeration of intestinal Enterococci bacteria in drinking waters for human consumption

Capital equipment required: Yes


Enterolert-DW is a liquid culture method that enumerates enterococci in drinking water and bathing water at 1 / 100 mL and 10 / 100 mL MPN respectively in the presence of heterotrophic bacteria in numbers as high as 1,000,000 MPN per 100 mL sample, providing confirmed results within 24 hours.

Principle: The Enterolert®-DW Test uses a Defined Substrate Technology (DST) nutrient indicator to enumerate enterococci. When coupled with the IDEXX Quanti-Tray® System, the Enterolert-DW Test provides quantitative confirmed results in 24 hours. The Enterolert-DW Test utilises ortho-nitrophenyl-β-D-glucoside as a nutrient indicator and incorporates a specifically designed blue background colour in its formulation. When the enzyme substrate is metabolised by enterococci, the sample turns from blue to green to indicate detection. Any change from the original colour to green is considered a positive result. No ultraviolet light source is required.

Approvals: AFNOR NF Validation (IDX 33/03-10/13) – Enterolert-DW/Quanti-Tray is validated for the enumeration of intestinal enterococci bacteria in drinking waters for human consumption (except bottled waters) and bathing waters (fresh bathing waters and marine bathing waters).

SCA Blue Book: Enterolert-DW is specified in the Methods for the Examination of Waters and Associated Materials (Blue Book) complied by the UK Standing Committee of Analysts. Ref: Microbiology of Drinking Water (MoDW) Part 5: Methods for the isolation and enumeration of enterococci (2012) – Enterolert-DW (Method B).

A more exhaustive list of approvals is available on request


Key Points:


  • More accurate when compared to ISO 7899-2 on all samples.
  • More accurate when compared to Microbiology of Drinking Water (MoDW) part 5 methods, on chlorine-stressed samples.
  • Liquid enrichment ensures optimised recovery.
  • Eliminates subjective interpretation of results determined by traditional methods.


  • Confirmed results in 24 hours.
  • Simplified quality control.
  • Less than 1 minute of hands-on sample preparation time.


  • Ready-to-use media.
  • Simple procedure.   
  • Provides Most Probable Number (MPN) enumeration.
  • Unit-dosed packaging eliminates media preparation.
  • Reagent contains no toxic compounds.




Company contact details:

IDEXX Laboratories Inc view full details
United States

Website: Visit Website
Tel: +1 800 321 0207