Himedia M189 500g TCBS Agar

TCBS Agar M189
Intended Use:
Recommended for the selective isolation and cultivation of Vibrio cholerae and other enteropathogenic Vibrio's
causing food poisoning from clinical and food specimen.
Composition**
Ingredients g / L
Proteose peptone 10.000
Yeast extract 5.000
Sodium thiosulphate 10.000
Sodium citrate 10.000
Bile 8.000
Sucrose 20.000
Sodium chloride 10.000
Ferric citrate 1.000
Bromo thymol blue 0.040
Thymol blue 0.040
Agar 15.000
Final pH ( at 25°C) 8.6±0.2
**Formula adjusted, standardized to suit performance parameters
Directions
Suspend 89.08 grams in 1000 ml purified/ distilled water. Heat to boiling to dissolve the medium completely. DO NOT
AUTOCLAVE.Cool to 45-50°C. Mix well and pour into sterile Petri plates.
Principle And Interpretation
TCBS Agar was developed by Kobayashi et al (1), who modified the selective medium of Nakanishi (2). Although this
medium was originally designed for the isolation of V.cholerae and V. parahaemolyticus, most Vibrio's grow to healthy large colonies with many different colonial morphologies. TCBS Agar is also recommended by APHA for the selective
isolation of V. cholerae and V. parahaemolyticus (3,4). Enrichment in Alkaline Peptone Water (M618), followed by
isolation on TCBS Agar is routinely used for isolation of V.cholerae (5,6,7).
Proteose peptone and yeast extract provide nitrogenous compounds, vitamin B complex and other essential growth nutrients.
Bile, a derivative of bile salts and sodium citrate inhibit gram-positive bacteria and coliforms (8). Sodium thiosulphate serves
as a good source of sulphur, which in combination with ferric citrate detects the production of hydrogen sulphide. For the metabolism of Vibrio's, sucrose is added as a fermentable carbohydrate. Vibrio that is able to utilize sucrose will from yellow colonies. Bromothymol blue and thymol blue are the pH indicators. The alkaline pH of the medium improves the recovery of V.cholerae. Strains of V. cholerae produce yellow colonies on TCBS Agar because of fermentation of sucrose.
V. alginolyticus also produce yellow colonies. V.parahaemolyticus is a sucrose non-fermenting organism and therefore
produces blue-green colonies, as does V.vulnificus.
Type of specimen
Clinical : faeces, etc; Food samples; Water samples.
Specimen Collection and Handling
For clinical samples follow appropriate techniques for handling specimens as per established guidelines (7,8).
For food and dairy samples, follow appropriate techniques for sample collection and processing as per guidelines (4,9,10).
For water samples, follow appropriate techniques for sample collection, processing as per guidelines and local standards (3).
After use, contaminated materials must be sterilized by autoclaving before discarding.

Warning and Precautions
In Vitro diagnostic use. For professional use only. Read the label before opening the container. Wear protective
gloves/protective clothing/eye protection/face protection. Follow good microbiological lab practices while handling
specimens and culture. Standard precautions as per established guidelines should be followed while handling clinical
specimens. Safety guidelines may be referred in individual safety data sheets.
Limitations
1. The medium should be inoculated heavily with faecal specimens because growth of few species may be inhibited on the
medium due to fermentation of sucrose and accumulation of acids.
2. However, occasional isolates of Pseudomonas and Aeromonas may also form blue green colonies on TCBS Agar (11).
3. Proteus species that are sucrose-fermenters may form yellow colonies (11).
4. TCBS Agar is not a suitable medium for oxidase testing of Vibrio species (12).
5. A few strains of V. cholerae may appear green or colourless on TCBS Agar due to delayed sucrose fermentation (11).
6. TCBS Agar is highly selective for Vibrio species. Any H2S negative colony of TCBS Agar can be considered presumptive
positive for Vibrio.
7. Further biochemical and serological tests must be carried out for complete identification.
Performance and Evaluation
Performance of the medium is expected when used as per the direction on the label within the expiry period when stored at recommended temperature.
Quality Control
Appearance
Light yellow to light tan homogeneous free flowing powder
Gelling
Firm, comparable with 1.5% Agar gel
Colour and Clarity of prepared medium
Bluish green coloured clear to slightly opalescent gel forms in Petri plates.
Reaction
Reaction of 8.9% w/v aqueous solution at 25°C. pH : 8.6±0.2
pH
8.40-8.80
Cultural Response
Cultural characteristics observed after an incubation at 35-37°C for 18-24 hours.

Storage and Shelf Life
Store between 10-30°C in a tightly closed container and the prepared medium at 20-30°C. Use before expiry date on the label. On opening, product should be properly stored dry, after tightly capping the bottle in order to prevent lump formation due to the hygroscopic nature of the product. Improper storage of the product may lead to lump formation.
Store in dry ventilated area protected from extremes of temperature and sources of ignition Seal the container tightly after use. Product performance is best if used within stated expiry period.
Disposal
User must ensure safe disposal by autoclaving and/or incineration of used or unusable preparations of this product. Follow
established laboratory procedures in disposing of infectious materials and material that comes into contact with clinical
sample must be decontaminated and disposed of in accordance with current laboratory techniques.