Cysteine lactose electrolyte deficient agar

From Wikipedia, the free encyclopedia
Jump to: navigation, search
A clear CLED agar plate after cultivation
Colonies of lactose and non-lactose fermenting bacteria on CLED agar

CLED agar (cysteine lactose electrolyte deficient medium) is a valuable non-inhibitory growth medium used in the isolation and differentiation of urinary organisms. Being electrolyte deficient, it prevents the swarming of Proteus species. Cysteine promotes the formation of cysteine-dependent dwarf colonies. Lactose fermenters produce yellow colonies on CLED agar; non-lactose fermenters appear blue. It has a pH of approximately 7.3. CLED agar contains:

Peptone 4g/l
'Lab Lemco' powder 3g/l
Tryptone 4g/l
Lactose 10g/l
L-Cysteine 128 mg/l
Bromothymol blue 20 mg/l
Agar No. 1 15g/l