used to culture and differentiate between species of Mycobacterium. It is said to be egg based because it uses a lot of homogenized eggs as its base. Also added are many inhibitors of growth. Mg sulphate and Mg citrate inhibit the growth of all other orgs except Mycobacterium. Malachite green inhibits any contaminants. Cycloheximide is an antifungal whilst lincoymcin and naladixic acid are antmicrobial.
You may well wonder why so many ways to prevent growth of other orgs. Simpe really. Culture of Mycobacterium requires incubation of up to 6 weeks. Imagine if both other microbes and fungi could grow uninhibited in this time. We would have to search high and low, narrow and wide, long and short to find the Mycobacteria. Remember that both fungi and regular ol' bacteria only require 18 to 24 hours to produce adequate growth. Another reason for the inhibitory substances relates to the specimen of choice, the sputum. The specimen would contain many normal flora along its route of expectoration. We don't want them!
Now the medium is pale green in colour, taken from malachite green which inhibits contaminants. It is not an agar plate, but a agar slant dispensed in small bottles with a screw top lid.
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