Enriched media:

• Always solid and allow growth of fastidious organism because of addition of specific nutritive substances in the media(blood, serum).
• Blood agar: nutrient agar + 5-10 % sheep blood. It is used to cultivate all fastidious organiksms.
• Chocolate agar: composition is same as blood agar. It is heated blood agar and used to culture influenza and N. gonorrhea.
• Loeffler’s serum slope: nutrient broth 100 ml + serum 300 ml + 1 gm glucose. This is used to cultivate Corynebacterium diptheriae.

Differential media:

• Differential media helps to differentiate differing properties of bacteria after culture.
• Mac Conkey’s agar: it contains lactose as substrate and neutral red as an indicator. Bacteria fermenting lactose produce acid and this changes the color of the indicator and colonies turn pink( acidic PH). This is used to cultivate enterobacteria and to differentiate lactose fermenters ( coli, Klebsiella) from non-lactose fermentors(Salmonella, Shigella).