Thiosulphate citrate bile salts sucrose (TCBS) agar is a selective medium used in microbiology laboratories to isolate Vibrio spp. The formulation was developed by Kobayashi et al. which was modified from Nakanishi’s formulation. The yeast extract and peptone are the source of the required nitrogen, carbon and vitamins. TCBS agar contains high concentrations of sodium thiosulphate, sodium citrate and ox bile to inhibit the growth of Gram-positive organisms and suppress coliforms. Sucrose is included as a fermentable carbohydrate for the metabolism of Vibrio spp. Sodium chloride maintains the osmotic balance in the medium. Sodium thiosulphate also serves as a sulphur source and, in combination with ferric citrate, detects hydrogen
sulphide production. Thymol blue and bromothymol blue are included as indicators of pH changes.
KM0008 – T.C.B.S Medium
Additional Information
| Shelf Life (days) | |
|---|---|
| Storage Temp (°C) | |
| Dehydrated Medium Appearance | |
| Prepared Medium Appearance | |
| Dehydrated Medium Colour | |
| Prepared Medium Colour | |
| Dehydrated PH | |
| Prepared PH | |
| Recommended Incubation |
Product Description
| Organisms | Ref. No | Result |
| Vibrio parahaemolyitcus | NCTC 10885 | Growth, green colonies |
| Vibrio furnissii | NCTC 12218 | Growth, yellow colonies |
| Vibrio chlorerae | NCTC 11348 | Growth, yellow colonies |
| Escherichia coli | NCTC 12241 | Inhibited |
Formula*
| g/L | |
| Yeast extract | 5.0 |
| Peptone | 10.0 |
| Sodium thiosulphate | 10.0 |
| Sodium citrate | 10.0 |
| Ox bile | 8.0 |
| Sucrose | 20.0 |
| Sodium chloride | 10.0 |
| Ferric citrate | 1.0 |
| Bromothymol blue | 0.04 |
| Thymol blue | 0.04 |
| Agar | 11.0 |
| Total | 85.0 |
| *Adjusted/supplemented as required to meet performance requirements |
Preparation
Suspend 85g/l of the medium in one litre of deionised / purified water. Allow the medium to soak whilst mixing for 10 minutes. Heat with frequent agitation until boiling. Cool to 45-50°C and aseptically dispense into appropriate sterile containers
NB: Protracted boiling or prolonged holding at elevated temperature induces precipitation.