☰ Sommaire :
Ⅰ. Overview
Trypticase Soy Agar (TSA), called Soybean-Casein Digest Agar Medium by the United States Pharmacopeia is a general-purpose nonselective growth medium that supports the growth of most Gram bacteria. -negative and non-fastidious Gram-positive as well as many yeasts and moulds.
This medium is recommended for use in the cultivation, storage, maintenance and transport of pure cultures of microorganisms (not intended for use in the diagnosis of disease or other conditions in humans ).
Note : Trypticase™ Soy Agar produced as a BBL product of BD Diagnostic Systems, Tryptone Soy Agar produced by Oxoid , and Tryptic Soy Agar produced by product of BD Diagnostic Systems have identical compositions.
Staphylococcus on TSA
Ⅱ. Composition of TSA agar
Suspend the components, dehydrated powder, in water (40 grams in 1000 ml of purified/distilled water). The medium is boiled for a few seconds until the ingredients are completely dissolved. Mix well and finally sterilize by autoclaving at 121°C for 15 minutes.
Cool to 45-50°C and dispense aseptically into sterile Petri dishes. Date the medium and assign it a lot number.
Tryptic soy agar composition |
|||
|---|---|---|---|
| Ingredients | gram/litre | ||
| Enzymatic Digest of Casein | 15g | ||
| Enzymatic Digest of Soybean | 5g | ||
| Sodium Chloride/td> | 5g | ||
| Agar | 15g | ||
TSA agar
Trypticase soy agar is prepared with casein and soy peptones: the combination of casein and soy peptones makes the medium nutritious by providing organic nitrogen in the form of amino acids and polypeptides. Sodium chloride maintains osmotic balance. Agar is the solidifying agent.
Formula may be adjusted and/or supplemented as required to meet performance specifications.
Ⅲ. Uses of Trypticase Soy Agar
☰ TSA medium is used for a multitude of purposes :
- Tryptone soy broth supplemented with dextrose, sodium chloride and agar is recommended for the cultivation of Salmonella Typhi.
- Trypticase soy agar with added salt can be useful in determining the level of halotolerance of microorganisms.
- It is useful for testing water, cosmetics, industrial products, food and beverages.
- Trypticase Soy Agar can also be used as a medium to maintain or subculture reference strains, eg Enterobacteriaceae and Staphylococci.
- TSA is often the base medium for other types of agar. For example, blood agar (GS) plates are made by enriching TSA plates with defibrinated sheep blood, and chocolate agar is made by additional cooking of GS.
- Trypticase Soy Agar does not contain growth factors X and V, it can be used to determine growth factor requirements by isolates of Haemophilus spp., by adding strips with factors X, V and XV in inoculated petri dishes.
TSA with sheep's blood
Staphylococcus on TSA
Serratia on TSA
Reference
- eurofins - Tryptic Soy Agar
- neogen - Tryptic Soy Agar
- BD Tryptic Soy Agar