Tryptic Soy Agar (TSA) with cycloheximide

Cat. no. G70 TSA with Cycloheximide, 15x100mm Plate, 18ml 10 plates/bag
Cat. no. H34 TSA with Cycloheximide, 15x150mm Plate, 70ml 10 plates/bag


Hardy Diagnostics Tryptic Soy Agar with Cycloheximide is recommended for use as a general growth medium for the isolation and cultivation of microorganisms while inhibiting Saprophytic fungal organisms.


The formulation of Tryptic Soy Agar is prepared according to the United States Pharmacopeia (USP) standard formula for Soybean-Casein Digest Agar Medium. (9) Tryptic Soy Agar contains digests of soybean meal and casein, making it suitable for the growth of a wide variety of fastidious and nonfastidious microorganisms. The combination of soy and casein peptones supply organic nitrogen in the form of amino acids and polypeptides, making the medium highly nutritious. Sodium chloride is added to maintain the osmotic equilibrium. Agar is the solidifying agent. The addition of cycloheximide makes it a selective medium inhibiting Saprophytic fungal organisms that may be present in a mixed flora sample.


Ingredients per liter of deionized water:*

Pancreatic Digest of Casein 15.0gm
Peptic Digest of Soybean Meal 5.0gm
Sodium Chloride 5.0gm
Cycloheximide 50.0mg
Agar 15.0gm

Final pH 7.3 +/- 0.2 at 25ºC.

* Adjusted and/or supplemented as required to meet performance criteria.


Storage: Upon receipt store at 2-8ºC away from direct light. Media should not be used if there are any signs of deterioration (shrinking, cracking, or discoloration), contamination, or if the expiration date has passed. Product is light and temperature sensitive; protect from light, excessive heat, moisture, and freezing.



Specimen Collection: Consult listed references for information on specimen collection. (1,2,5) Infectious material should be submitted directly to the laboratory without delay and protected from excessive heat and cold. If there is to be a delay in processing, the specimen should be inoculated onto an appropriate transport medium and refrigerated until inoculation.

Method of Use: Plates should be warmed to room temperature and the agar surface should be dry prior to inoculating. Inoculate and streak the specimen as soon as possible after collection.

If the specimen to be cultured is on a swab, roll the swab over a small area of the agar surface. Streak for isolation with a sterile loop. Incubate plates aerobically at 35-37ºC. for 18-24 hours (some organisms may take longer than 24 hours for visible growth to appear). Examine for colonial morphology.

Spread Plate Method:

1. Prepare decimal dilutions in sterile diluent to obtain 30-300 CFU per plate.

2. Aseptically inoculate agar surface with 0.1ml of well-mixed diluted sample.

3. Using a sterile spreader device, distribute the inoculum evenly over the agar surface.

4. Incubate plates aerobically for 1 to 5 days at 35ºC.


Consult listed references for the identification of colony morphology and further biochemical tests required for identification. (1-5)

Following incubation, examine the plates for growth. Count the number of colonies and express in number of colony forming units (CFU) per gram or milliliter of sample. (Take into account the dilution factor.) If duplicate plates were set up, express the average for the two plates in terms of the number of microorganisms per gram or milliliter of sample. Consult listed references for additional information on interpretation and enumeration of microbial growth on this medium. (2-5,8)



Standard microbiological supplies and equipment such as loops, swabs, applicator sticks, other culture media, incinerators, and incubators, etc., as well as serological and biochemical reagents, are not provided.


Test Organisms Inoculation Method* Incubation Results
Time Temperature Atmosphere
Staphylococcus aureus
ATCC ® 25923
A 18-24hr 35°C Aerobic Growth
Escherichia coli
ATCC ® 25922
A 18-24hr 35°C Aerobic Growth
Candida albicans
ATCC ® 10231
A 18-24hr 35°C Aerobic Growth
Aspergillus brasiliensis
ATCC ® 16404
G 48hr 20-25°C Aerobic Partial to complete inhibition



1. Anderson, N.L., et al. Cumitech 3B; Quality Systems in the Clinical Microbiology Laboratory, Coordinating ed., A.S. Weissfeld. American Society for Microbiology, Washington, D.C.

2. Jorgensen., et al. Manual of Clinical Microbiology, American Society for Microbiology, Washington, D.C.

3. Tille, P., et al. Bailey and Scott's Diagnostic Microbiology, C.V. Mosby Company, St. Louis, MO.

4. American Public Health Association. Standard Methods for the Examination of Water and Wastewater, APHA, Washington, D.C.

5. Isenberg, H.D. Clinical Microbiology Procedures Handbook, Vol. I, II & III. American Society for Microbiology, Washington, D.C.

6. MacFaddin, J.F. Biochemical Tests for Identification of Medical Bacteria, , Lipincott Williams & Wilkins, Philadelphia, PA.

7. Quality Assurance for Commercially Prepared Microbiological Culture Media , M22. Clinical and Laboratory Standards Institute (CLSI - formerly NCCLS), Wayne, PA.

8. APHA Technical Committee on Microbiological Methods for Foods. Compendium of Methods for the Microbiological Examination of Foods, APHA, Washington, D.C.

9. The Official Compendia of Standards. USP-NF . United States Pharmacopeial Convention, Rockville, MD.

ATCC is a registered trademark of the American Type Culture Collection.