|Eosin Methylene Blue Agar
|Escherichia coli on EMB Agar. Note the dark
colonies surrounded by a metallic-green halo
Inoculate and incubate at 35 °C for 18-24 hours:
- Enterococcus faecalis ATCC 29212: partial inhibition.
- Escherichia coli ATCC 25922: good growth, black and green-metallic colonies due
to lactose fermentation.
- Proteus vulgaris ATCC 9484: good growth, colorless colonies
- Salmonella typhi ATCC 19430: good growth, colorless colonies
- Salmonella typhimurium ATCC: good growth, colorless colonies
Peptone from meat 10 g, Bipotasic phosphate 2 g, Lactose 10 g, Eosin G 0.4 g,
Methylene blue 0.065 g, Agar 15 g, Distilled water ad 1000ml.
Autoclave at 121 ºC for 15 minutes. Aspect: red-purple coloured, opalescent gel with
greenish cast .
Selective and differential medium for the isolation, cultivation and differentiation of
Entrobacteriaceae (coliforms) from foods, water, feces and pathologic materials.
The eosin and methylene blue inhibits most Gram-positive bacteria but allows
growing of many Gram-negative organisms.
Gram-negative bacteria that ferment the lactose produce acid which turns the
colonies dark purple as the acid acts upon the dyes. Strong lactose-fermenting
bacteria produce flat, dark colonies with a green metallic sheen.
|Geam-Levine (EMB Agar Levine)
Eosin Methylene Blue Agar
(c) Costin Stoica