IDEXX, a global leader in rapid microbiological testing for water, has announced that the Enterolert™-DW method has been officially published as the International Organization for Standardization (ISO) Standard 7899-3:2025 for the enumeration of intestinal enterococci in drinking and fresh and marine bathing waters.
This development aligns with the revision to the European Union Drinking Water Directive (Directive (EU) 2020/2184) and the European Union Bathing Water Directive, (Directive 2006/7/EC), both of which recognise enterococci – alongside E. coli - as a key faecal contamination indicator for assessing water quality.
Achieving ISO standard status involves a rigorous evaluation process that undergoes thorough scrutiny by experts from around the world. Performance characteristics established in accordance with ISO 13843 confirm that Enterolert-DW is a reliable and suitable method for monitoring intestinal enterococci in drinking, as well as in fresh and marine bathing waters. Furthermore, Enterolert-DW demonstrates accuracy, sensitivity, and specificity comparable to, or exceeding, that of ISO 7899-2 across all sample types.
Listed under ISO 7899-3:2025, Water Quality—Enumeration of Intestinal Enterococci–Part 3: Most Probable Number Method, the Enterolert-DW has the following benefits:
- Rapid enumeration: Detects and enumerates enterococci in just 24 hours without requiring additional confirmation steps
- Minimal hands-on time: Requires less than one minute of active laboratory work, improving efficiency and workflow
- High sensitivity: Capable of detecting as few as one enterococcus per 100 mL of sample, ensuring reliable detection even at low concentrations
- Simple result interpretation: Uses an intuitive color-change system where samples turn from blue to green when enterococci metabolize the enzyme substrate
- Clear positive indication: Any change from the original blue color to green is considered a positive result, eliminating ambiguity in interpretation
- Streamlined workflow: Eliminates the need for complex confirmation procedures, reducing overall testing time and laboratory resources
This international recognition follows Enterolert-DW’s inclusion in the UK Standard Committee of Analysts’ Blue Book, “The Microbiology of Drinking Water (Part 5)”; its AFNOR Certification NF Validation under the reference 33/03-10/13; and its approval by the respective regulators in Germany, Spain, Italy, Ireland, Belgium, Portugal, and many others.
The acceptance of Enterolert-DW as an ISO standard marks the third such recognition for an IDEXX Water method. It follows the Colilert™-18 method, published as an ISO standard (ISO 9308-2) in 2012 for the 18-hour detection of E. coli and coliforms, and Pseudalert™, published as ISO standard (ISO 16266-2:2018) in 2018 for the 24-hour detection of Pseudomonas aeruginosa.
To learn more about IDEXX Enterolert-DW, register for the upcoming webinar: Enterolert-DW: ISO 7899-3 Recognized Method for Enumerating Enterococci in Drinking & Bathing Waters or visit the IDEXX website.
