STARCH AGAR WITH BROMCRESOL PURPLE

Cat. no. J181 V Agar / Starch Agar with Bromcresol Purple,
15x100mm Biplate, 10ml/10ml
10 plates/bag

INTENDED USE

Hardy Diagnostics Starch Agar with Bromcresol Purple is recommended for use in the differentiation of Gardnerella vaginalis from genitourinary specimens.

SUMMARY

Starch Agar with Bromcresol Purple contains starch to aid in the differentiation of Gardnerella vaginals ( Haemophilus vaginalis , Corynebacterium vaginale ) from other microorganisms commonly found in the genitourinary tract. (2-5) The medium contains animal peptone, which supplies nitrogen, vitamins, carbon and amino acids to support cell growth. Corn starch provides the target for enzymatic digestion. Bromcresol purple is the pH indicator and agar is the solidifying agent.

Acid byproducts released during the enzymatic breakdown of starch create a pH shift in the medium. Consequently, microorganisms, such as G. vaginalis , capable of hydrolyzing starch will exhibit colonies surrounded by a yellow zone.

FORMULA

Ingredients per liter of deionized water:*

Corn Starch 10.0gm
Peptic Digest of Animal Tissue 10.0gm
Bromcresol Purple 1.2ml
Agar 15.0gm

Final pH 7.0 +/- 0.2 at 25ºC.

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

STORAGE AND SHELF LIFE

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.

PRECAUTIONS

PROCEDURE

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

Method of Use:

1. Bring medium to room temperature prior to use.

2. Inoculate the surface of the medium with an 18-24 hour old pure culture and streak the specimen for isolation.

3. Incubate plates at 35ºC. for 24-48 hours using an atmosphere enriched with 5-10% CO 2 : a candle jar, CO 2 incubator or CO2Gen Compact (Cat. no. CD020C) may be used.

INTERPRETATION OF RESULTS

G. vaginalis appears as small, yellow colonies surrounded by a yellow zone in the medium. The yellow color change is a positive test for starch hydrolysis.

LIMITATIONS

G. vaginalis isolates should be incubated in a 5-10% CO 2 enriched atmosphere for best results.

MATERIALS REQUIRED BUT NOT PROVIDED

Standard microbiological supplies and equipment such as loops, other culture media, swabs, applicator sticks, incinerators, and incubators, atmospheric chambers, CO2Gen (Cat. no. CD020C), etc., as well as serological and biochemical reagents, are not provided.

QUALITY CONTROL

Test Organisms Inoculation Method* Incubation Results
Time Temperature Atmosphere
Gardnerella vaginalis
ATCC ® 14018***
A 24-48hr 35°C CO 2 ** Growth; yellow color change
Enterococcus faecalis
ATCC ® 29212***
A 24-48hr 35°C CO 2 ** Growth; no color change

** Atmosphere of incubation is enriched with 5-10% CO 2 .

*** Recommended QC strains for User Quality Control according to the CLSI document M22 when applicable.

User Quality Control

PHYSICAL APPEARANCE

Starch Agar with Bromcresol Purple should appear slightly opalescent, and purple in color.

G. vaginalis growing on Starch Agar with Bromcresol Purple

Gardnerella vaginalis (ATCC ® 14018) colonies growing on Starch Agar with Bromcresol Purple (Cat. no. J181). Incubated aerobically for 48 hours at 35ºC.

E.faecalis growing on Starch Agar with Bromcresol Purple

Enterococcus faecalis (ATCC ® 29212) colonies growing on Starch Agar with Bromcresol Purple (Cat. no. J181). Incubated aerobically for 24 hours at 35ºC.



Starch Agar with Bromcresol Purple

Uninoculated plate of Starch Agar with Bromcresol Purple (Cat. no. J181).



REFERENCES

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. Koneman, E.W., et al. Color Atlas and Textbook of Diagnostic Microbiology, J.B. Lippincott Company, Philadelphia, PA.

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


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

041816gr