A chromogenic medium for the detection of Enterococci.

Peptones	26.0
Sodium chloride	8.5
Growth factors	7.3
Phosphate buffer	5.0
Agar	13.0
Chromogenic substrates	200.0 mg
Selective compounds	27.0 mg

Kanamycin Selective Supplement - (for 500 ml of medium):

Kanamycin Sulphate - 10 mg

pH 7.2 +/- 0.2

Directions

Suspend 30g in 500ml of cold distilled water. Bring to the boil to dissolve completely. Sterilise by autoclaving at 121°C for 15 minutes. Cool to 50°C and add the contents of one vial of Kanamycin Selective Supplement reconstituted with 5 ml of sterile distilled water. Mix well to suspend the flocculent blue precipitate and distribute into sterile Petri dishes.

E.C.O.A. AGAR is a selective and differential medium, for the isolation, enumeration and immediate identification of enterococci, from foodstuffs, environmental samples and clinical specimens. The selectivity of the medium is obtained by the presence of a mixture of antibiotic compounds including kanamycin. The differentiation of the colonies is obtained by the presence of a chromogenic mixture to detect specific enzymatic activities of enterococci and of contaminating bacteria. The medium can be used according to usual laboratory techniques with surface inoculation technique, pouring plated technique or with MF procedure for liquid samples. Enterococci grow with blue or green-blue colonies after incubation at 37°C for 24 hours. The rare non-enterococci strains resistant to the selective agents grow with violet colonies.

E.faecalis ATCC 19433: good growth, green-blue colonies

E.coli ATCC 25922: inhibited

Dehydrated medium: 15-30°C

User prepared plates and flasks: one week at 2-8°C