Chromogenic E.coli / Coliform Agar

It is used as a selective solid medium for the detection and enumeration of coliform group bacteria and E. coli in microbiological analysis.

B-D—galactosidase enzyme characteristic for coliform bacteria degrades the Salmon-GAL chromogenic substrate, allowing coliform bacteria to form pinkish red colonies.

The X—Glucuronide substrate in the composition is characteristic for E. coli.

It is degraded by the enzyme B-D-Gluouronidase.

Thus, besides breaking down Salmon-GAL as E. coli coliform bacteria

It is differentiated from other coliform bacteria by the formation of dark blue-violet colonies by decomposing the X—Glucuronide substrate.

The presence of tryptophan in the medium composition allows indole testing directly on the colony.

Gram negatives form the colorless colon.

Some of them are open due to B—D-Gluouronidase activity.

They form blue-turquoise colored colonies.