RAPID TREHALOSE BROTH

Cat. no. Z205 Rapid Trehalose Broth, 13x100mm Tube, 0.35ml 20 tubes/box

INTENDED USE

Hardy Diagnostics Rapid Trehalose Broth is a rapid screening method to aid in the detection of Candida (Torulopsis) glabrata.

SUMMARY

Within the genus Candida, C. albicans is the most frequently isolated as the cause of disease in clinical labs. However, the need to screen for Candida glabrata has risen in importance as it has been isolated as the cause of major infections, particularly in immunosuppressed patients.

Hardy Diagnostics Rapid Trehalose Broth is a rapid screening method for C. glabrata on the basis of rapid trehalose assimilation at 42ºC. Candida glabrata is capable of utilizing trehalose more quickly than other Candida species. The elevated incubation temperature increases the specificity of the test.

Rapid Trehalose Medium is derived from the formula described by Stockman and Roberts.(6) It utilizes yeast nitrogen base as a source of nitrogenous compounds. Yeast nitrogen base is low in other carbohydrates that might interfere with the rapid test. Bromcresol green is the indicator, allowing the visualization of an acid shift that is indicative of a positive reaction. Trehalose is incorporated into the medium at a high concentration as the carbon source. This product is best used in conjunction with HardyCHROM™ Candida (Cat. no. G301). C. glabrata will appear as smooth pink colonies, often with a darker pink or mauve center, on this screening method and should be confirmed with the trehalose test.

FORMULA

Ingredients per liter of deionized water:*

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Trehalose 40.0gm
Yeast Nitrogen Base 10.7gm
Bromcresol Green 20.0mg

Final pH 5.4 +/- 0.1 at 25ºC.

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

STORAGE AND SHELF LIFE

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

PRECAUTIONS

PROCEDURE

Specimen Collection: This product is not intended for the primary isolation of patient specimens. This product is intended to be used in conjunction with other biochemical and/or serologic tests to identify cultures of isolated organisms.

1. Obtain isolated colonies that are 24-48 hours old, preferably from HardyCHROM™ Candida (Cat. no. G301).

2. Inoculate the Rapid Trehalose Broth with the yeast isolate, creating a suspension at least as dense as a 1.0 McFarland Standard.

3. Incubate the test at 42ºC. for three hours.

4. Observe for a color change from blue to yellow. Do not read the tubes after three hours.

INTERPRETATION OF RESULTS

C. glabrata appear microscopically as tiny budding yeast cells with no hyphae, pseudohyphae, blastospores or chlamydospores. C. glabrata colonies will appear as smooth pink, often with darker pink to mauve centers, on HardyCHROM™ Candida (Cat. no. G301).

A positive Rapid Trehalose Broth test is indicated by a color change from blue to yellow within three hours. This is indicative of C. glabrata.

Negative tests in Rapid Trehalose Broth remain green-yellow, green, or blue. These reactions are indicative of yeast isolates other than C. glabrata.

Typical reactions of common Candida species.(1)*

Organism Rapid Trehalose Germ Tube Morphology on
Corn Meal Agar with Tween®
Color on
HardyCHROM™ Candida
(Cat. no. G301)
Pseudo-
or
true-hyphae
Blasto-
condidia
Chlamydospores
C. glabrata + - - - - Light pink to pink, with a darker pink or mauve center
C. albicans - + + + + Emerald green to metallic green
C. tropicalis - - + + - Dark blue to metallic blue with blue halos

* Some strain to strain variation may occur, and isolates may require more biochemical and/or serological tests for complete identification. Refer to the listed references for more information regarding the identification and differentiation of Candida species.

LIMITATIONS

This medium is intended to be used a screening medium for C. glabrata. Rare clinical strains of C. glabrata have demonstrated weak reactions with Rapid Trehalose media. Other biochemical and/or serological tests may be required for complete identification of this organism.

Rare Candida tropicalis strains may give a false-positive reaction in Rapid Trehalose Broth.

Do not incubate longer than 3 hours. Extended incubation times may lead to erroneous results.(7)

A heavy inoculum must be used. The turbidity of the Rapid Trehalose Broth should be at least equivalent to a 1.0 McFarland Standard after inoculation. Tubes that are inoculated too lightly may give false-negative reactions.(7)

MATERIALS REQUIRED BUT NOT PROVIDED

Standard microbiological supplies and equipment such as loops, slides, staining supplies, other culture media, microscopes, incinerators, and incubators, etc., as well as serological and biochemical reagents, are not provided.

QUALITY CONTROL

Test Organisms Inoculation Method* Incubation Results
Time Temperature Atmosphere
Candida glabrata
ATCC® 66032
* 3hr 42°C Aerobic Positive; media becomes yellow
Candida albicans
ATCC® 60193
* 3hr 42°C Aerobic Negative; media remains blue
Candida tropicalis
ATCC® 750
* 3hr 42°C Aerobic Negative; media remains blue

User Quality Control

PHYSICAL APPEARANCE

Rapid Trehalose Broth should appear clear, and dark blue in color.

Positive Trehalose Reaction

Candida glabrata (ATCC® 66032) growing in Rapid Trehalose Broth (Cat. no. Z205). The yellow color change within three hours was indicative of a positive trehalose reaction. Incubated aerobically for three hours at 42ºC.

Negative Trehalose Reaction

Candida albicans (ATCC® 60193) growing in Rapid Trehalose Broth (Cat. no. Z205). No yellow color change within three hours was indicative of a negative trehalose reaction. Incubated aerobically for three hours at 42ºC.

REFERENCES

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

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

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

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

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

6. Stockman, L. and G. Roberts. 1985. Abstracts of Annual Meeting of American Society of Microbiology, p.377 (F-80). Washington, D.C.

7. Hardy Diagnostics. 1998. Internal testing results.


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

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