Cat. no. Y130 Pyruvate Broth, 16x100mm Tube, 5ml 20 tubes/box


Hardy Diagnostics Pyruvate Broth is recommended for the differentiation of microorganisms based on pyruvate utilization.


The ability of bacteria to form organic compounds by metabolizing certain carbohydrates and related compounds is a widely used method for the identification of microorganisms. Acid is produced as a metabolic waste when Pyruvate Broth is inoculated with bacteria that are capable of metabolizing pyruvate. Acid production causes a decrease in pH which results in a color shift in the medium. Bromothymol blue is the acid-base indicator in the media. It is greenish-blue at an alkaline pH, and shifts to yellow when acid is produced during fermentation of the pyruvate. After incubation, yellow media is indicative of a positive fermentation reaction.

Pyruvate Broth contains casein peptone, sodium chloride, yeast extract, dipotassium pyruvate, and bromothymol blue. Casein peptone and yeast extract provide the nutrients and growth factors necessary for growth and the sodium chloride maintains osmotic balance. Sodium pyruvate is added as the fermentable ingredient and bromothymol blue is the acid-base indicator. Dipotassium phosphate is added as a buffering system.


Ingredients per liter of deionized water:*

Pancreatic Digest of Casein 10.0gm
Sodium Pyruvate 10.0gm
Yeast Extract 5.0gm
Dipotassium Phosphate 5.0gm
Sodium Chloride 5.0gm
Bromothymol Blue 0.04gm

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.



1. Inoculate with 2-3 colonies from a 18-24 hour culture.

2. Incubate aerobically at 35ºC. for up to 5 days.

3. Examine daily for a yellow reaction.


Pyruvate fermentation, and thus, acid production, is indicated by the appearance of a yellow color in the broth within 5 days following inoculation. A negative result is noted when the medium remains greenish-blue.



Standard microbiological supplies and equipment such as loops, other culture media, swabs, applicator sticks, incinerator, and incubators, etc., are not provided.


Test Organisms Inoculation Method* Incubation Results
Time Temperature Atmosphere
Enterococcus faecalis
ATCC® 29212
A 24hr 35°C Aerobic Growth; media turns yellow
Enterococcus faecium
ATCC® 700221
A 24hr 35°C Aerobic Growth; no color change or turns blue

User Quality Control


Pyruvate Broth should appear slightly hazy, and blue to blue-green in color.

E. faecium growing in Pyruvate Broth

Enterococcus faecalis (ATCC® 29212) growing in Pyruvate Broth (Cat. no. Y130). The yellow color development was indicative as positive for pyruvate utilization. Incubated aerobically for 24 hours at 35ºC.

E. faecium growing in Pyruvate Broth

Enterococcus faecium (ATCC® 700221) growing in Pyruvate Broth (Cat. no. Y130). No yellow color development was indicative as negative for pyruvate utilization. Incubated aerobically for 24 hours at 35ºC.


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

5. Schleifer, K.H. 1986. Bergey's Manual of Systematic Bacteriology. Vol. II. Williams & Wilkins, Baltimore, MD.

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