
Sodium Citrate, Sodium Thiosulfate, Sodium Cholate, and Oxbile inhibit Gram-positive organisms and suppress
coliforms. An increased pH is used to favorize the growth of vibrios. Sucrose is the fermentable carbohydrate.
Sodium Chloride stimulates organism growth and maintains osmotic balance of the medium. Sodium Thiosulfate is
also a sulfur source, and acts with Ferric Citrate as an indicator to detect hydrogen sulfide production. Bromthymol
Blue and Thymol Blue are pH indicators.
PROCEDURE
Inoculate the plates and incubate aerobically,18 – 24 hours, at 35°C.
RESULTS
Sucrose-fermenting vibrios appear smooth, opaque, thin-edged yellow colonies. Non-sucrose-fermenting colonies
appear green.
QUALITY CONTROLS
Growth of Enterococcus faecalis ATCC 29212 & Escherichia coli ATCC 25922 is inhibited.
Vibrio alginolyticus ATCC 17749 & Vibrio cholerae ATCC 9459 produce yellow colonies.
Vibrio parahaemolyticus ATCC 17802 produces green colonies.
Pseudomonas aeruginosa ATCC 27853 is partially to completely inhibited; forms blue colonies.
COMPOSITION
Yeast extract ........................................................................0,5 % (vol)
Peptone ...............................................................................1,0 %
Na thiosulphate ....................................................................1,0 %
Sodium citrate .....................................................................1,0 %
Bile ......................................................................................0,8 %
Saccharose ..........................................................................2,0 %
NaCl .....................................................................................1,0 %
Fe citrate ............................................................................. 0,1 %
Bromothymol blue ............................................................0,004 %
Thymol blue .....................................................................0,004 %
Agar ......................................................................................1,4 %
Adjust pH to 8.6, bring to boiling temperature. Do not autoclave.
DESCRIPTION
Medium frequently used for the selective isolation of Vibrio cholerae and other enteropathogenic vibrios.
TCBS medium (Thiosulfate-Citrate-Bile-Sucrose Agar)
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(c) Costin Stoica