Please find the following link for the US EPA method
Method 1106.1: Enterococci in Water by Membrane Filtration Using membrane-Enterococcus-Esculin Iron Agar (mE-EIA) (September 2002)7 (PDF, 16 pp., 806 KB)
Summary - This method (EPA 821-R-02-021) combines information from a 1985 publication (Test methods for Escherichia coli and Enterococci in Water by the Membrane Filter Procedure, EPA 600-4-85-076) and a subsequent March 2000 manual (Improved Enumeration Methods for the Recreational Water Quality Indicators: Enterococci and Escherichia coli, EPA/821/R-97/004). Method 1106.1 is a membrane filter (MF) procedure for the detection and enumeration of enterococci in water. The method incorporates the sequential use of a selective medium, mE agar, and a differential medium, EIA agar.