CLED ( Cysteine Lactose Electrolyte Deficient Media )- Inhibits growth of other commensals & allows staphylococcus and Candida to grow. It enhaces the growth of dwarf colonies of coliforms d/t presence of cysteine McConkey and CLED both prevent swarming of Proteus and differentiate between LF and NLF. Gram positive organisms usually can't grow in McConkey, it is selective for gram negative organisms.