CLED MEDIUM with ANDRADE'S INDICATOR

 

A non-inhibitory medium recommended for the total microbial count in urine tract infections with Bevis modification to formulation.o:p>

 

Code: CB1/1019

 

Typical Formula g/l

 

Peptone	7.00
Tryptone	4.00
Lactose	10.00
L-Cysteine	0.128
Bromo thyme blue	0.020
Andrade's indicator	0.100
Agar	15.00

 

Final pH 7.5 +/- 0.2

 

Directions

Suspend 36g in 1000 ml of cold distilled water; heal to boiling to dissolve completely. Sterilise by autoclaving at 121^°C for 15 minutes.

 

Description

Cystine Lactose Electrolyte Deficient (CLED) Medium with Andrade indicator is a non-inhibitory medium, particularly recommended for the total microbial enumeration in urine.

It differs from CLED medium because of the in­troduction in the formula of the Andrade’s indicator, which allows a better differentiation of the colonies. Lactose is present in the medium as a fermentable carbohydrate. The lactose fermenting bacteria aci­dify the medium in a more or less intense way, with a colour change of Andrade indicator to different red tones and bromothymol blue to yellow; the lactose non-fermenting bacteria cause an alkalisation of the substrate with a colour change of the indicators to blue-green.

 

User quality assurance   (37°C - 24 h)

 

Productivity control

E. coli ATCC 25922: good growth, red colonies with red halo

S. aureus ATCC 25923: good growth, light pink, small colonies

P. vulgaris ATCC 8427: good growth, green-blue, not swarming colonies

 

Storage

Dehydrated medium: 15-30°C

User prepared plates: 1month at 2-8°C

 

References  

Bevis, T. D. A modified electrolyte-deficient culture medium, (1968) J.Med. Lab. Techn. 25: 38-41.