Enterococcus faecalis ATCC 29212: good growth; brown coloured colonies by
Streptococcus pyogenes ATCC 19615: no growth.
1. CM0888 Bile Esculin Agar. Oxoid - product leaflet.
2. 48300 Bile Esculin Agar. Millipore - product leaflet.
Peptone 14.0 g, Bile salts 15.0 g, Ferric citrate 0.5 g, Esculin (aesculin) 1.0 g, Agar
14.0 g. Distilled water ad 1000 ml, pH 7.1 ± 0.2.
Bring to the boil to dissolve the agar completely. Sterilise by autoclaving at 121 ºC for
15 minutes. Dispense into Petri dishes.
BEA is used for bile esculin test which is based on the hydrolysis of esculin into
esculetin (6, 7-dihydroxy-coumarin) and glucose by the microorganisms that produce
the enzyme esculinase.
The medium is used for isolation and presumptive identification of group D Streptococci and Enterococci based on the organism’s
potential to hydrolyze esculin.
(c) Costin Stoica
|Enterococcus faecium brown halo around colonies
Using a sterile loop inoculate the medium with 4-5 colonies and incubate at 37 ºC
for 18-24 hours.
The result is positive for bile salt tolerance and aesculin hydrolysis if blackening of
the medium occurs.