Tryptic Soy Agar Composition, Principle, Preparation, Results, Uses

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Tryptic Soy Agar can be used to grow microorganisms. These media are non-selective and general-purpose. They provide enough nutrients to support a variety of microorganisms. This medium can also be used to grow, store, maintain, and transport pure microorganism cultures.

Principle of Tryptic Soy Agar

The pancreatic digest of soybean meal and papaic digest are rich in nitrogen, vitamins, as well as minerals. It is suitable for the growth and maintenance of many fastidious as well as non-fastidious microorganisms. Glucose is a carbohydrate source. The media is protected by phosphate. The osmotic equilibrium is maintained by sodium chloride. Agar acts as a solidifying agent.

To facilitate the growth and maintenance of fastidious bacteria, the medium can be supplemented by blood. Minor adjustments may be required to meet specific circumstances.

Composition of Tryptic Soy Agar

Ingredients	Gms/liter
Pancreatic digest of casein	17.000
Papaic digest of soybean meal	3.000
Sodium chloride	5.000
Dextrose (Glucose)	2.500
Dipotassium hydrogen phosphate	2.500
Agar	15.000

Final pH (at 25°C): 7.3±0.2

Principle of Tryptic Soy Agar

To facilitate the growth and maintenance of fastidious bacteria, the medium can be supplemented by blood. Minor adjustments may be required to meet specific circumstances.

Preparation and Method of Use of Tryptic Soy Agar

Take 45 grams and mix it with 1000 ml of distilled water.
To dissolve the medium completely, heat to boiling
For 15 minutes, sterilize by using an autoclave at 15lbs pressure (121degC).
Keep it at 45-50 degrees Celsius
Mix everything together and pour onto sterilized Petri dishes.
Before inoculating, plates should be brought to room temperature.
As soon as possible after collecting the specimen, innoculate it and streak it.
If the specimen is to be cultured on a swab then roll the swab across a small area of the surface of the agar.
Streak for isolation using a sterile loop
For 18-24 hours, incubate plates at 35-37degC. Some organisms may require more time for visible growth.
Investigate the morphology of colonial cells.

Result Interpretation on Tryptic Soy Agar

Organisms	Growth
Aspergillus brasiliensis	Positive
Candida albicans	Positive
Staphylococcus aureus	Positive; pigmented shiny round colonies
Staphylococcus epidermidis	Positive
Bacillus subtilis	Positive; flat, large irregular colonies
Pseudomonas aeruginosa	Positive
Escherichia coli	Positive; shiny round colonies
Salmonella Typhimurium	Positive

Uses of Tryptic Soy Agar

This medium can be used for many purposes, including culture storage, counting cells, isolation of pure cultures or general culture.
Tryptic Soy Agar supports the development of many organisms, including fastidious and not-fastidious like Neisseria and Listeria and Brucella.
For the cultivation of Salmonella Typhi, tryptone soya broth with sodium chloride and added dextrose.
TSA is often used as the base medium for other types of agar plates. Blood agar plates (BAP), for example, are made by enriching TSA plates in defibrinated sheep’s blood. Chocolate agar is created through further cooking of BAP.
It can be used for determining the X, V and XV factors in Hemophilus species by using strips that contain the factors V, XV and XV on the inoculated plates.
The addition of salt to tryptic soyagar can help determine the halotolerance levels of microorganisms.
It is used in pharmaceutical testing.
It can be used to test water, cosmetics and industrial food.
You can also use Tryptic Soy Agar as a medium to maintain or subculturing reference species, e.g. Enterobacteriaceae or staphylococci.

Limitations of Tryptic Soy Agar

For complete identification, it is recommended that colonies grown from pure culture be subject to biochemical, immunological and molecular testing.
Because it doesn’t promote certain types of fastidious bacteria, tryptic soyagar is not recommended for microbiology.
It can’t be used to isolate pathogens in clinical specimens.