Used in microbiology to isolate and identify enterococci from clinical and non-clinical samples. The medium inhibits the growth of most gram-negative bacteria and many gram-positive organisms due to the azide component, allowing selective growth of enterococci. Aesculin hydrolysis by enterococci produces a blackening of the medium, enabling easy differentiation from other bacteria. Commonly used in water quality testing, food safety, and clinical diagnostics to detect enterococcal contamination.