CARBON UTILIZATION MEDIA - for identification of Mycobacteria

Cat. no. Y125 Carbon Utilization Base, 20x125mm Tube, 8ml Slant 20 tubes/box
Cat. no. Y126 Carbon Utilization with Inositol, 20x125mm Tube, 8ml Slant 20 tubes/box
Cat. no. Y127 Carbon Utilization with Mannitol, 20x125mm Tube, 8ml Slant 20 tubes/box
Cat. no. Y128 Carbon Utilization with Citrate, 20x125mm Tube, 8ml Slant 20 tubes/box

INTENDED USE

Hardy Diagnostics Carbon Utilization Media with added carbon sources are recommended for use in the cultivation and differentiation of a wide variety of rapidly growing mycobacteria.

SUMMARY

Once an acid-fast isolate has been assigned to a specific subgroup on the basis of pigment and growth rate, species identification can be accomplished by the performance of a battery of in vitro tests. (6) Carbon source testing is a biochemical test that assists in the detection of subtle differences between thirty or more species of rapidly growing Mycobacterium . (1-3,6)

This test is significant as at least three of the rapidly growing Mycobacterium have been associated with disease in humans. M. fortuitum , M. chelonae , and M. abscessus can cause cutaneous, pulmonary, and nosocomial infections while M. smegmatis , M. peregrinum , and M. mucogenicum have also been associated with rare disease in humans. (2,3,6)

This media measures the ability of certain rapid growers to metabolize several carbon sources in the presence of ammoniacal nitrogen: inositol, mannitol, and citrate. The test is run on the desired carbon source media as well as on the basal control medium, which lacks an available carbon source. Growth on the test medium and not on the basal control confirms a positive finding and demonstrates that the organism is capable of utilizing the carbon source. The absence of growth on both the test slant and the control slant indicate a negative finding. (1-3,6,11)

FORMULA

Ingredients per liter of deionized water:*

Carbon Source** 5.0-5.6gm
Ammonium Sulfate 2.4gm
Monopotassium Phosphate 0.5gm
Magnesium Sulfate 0.5gm
Agar 20.0gm

Final pH 6.9 +/- 0.2 at 25ºC.

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

** 5.0gm, 5.0gm, and 5.6gm of the appropriate carbon source are added to the Mannitol, Inositol and Citrate Media, respectively. There is no carbon source addition to the Basal Control Media.

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 (6)

Specimen Collection: Infectious material should be submitted directly to the laboratory without delay and protected from excessive heat and cold. Consult listed references for information on specimen collection. (1-3,6,7)

1. Perform serial dilutions with deionized water on a seven day old 7H9 Broth culture of the test organism until turbidity is no longer visible.

2. Inoculate 0.1ml of this last suspension onto the carbon source media and to the control slant.

3. All slants should be incubated at 28ºC. aerobically for two weeks before interpreting the results.

INTERPRETATION OF RESULTS

Growth on the carbon source slant but not on the control slant is indicative of a positive finding. A negative finding can only be noted when there is no growth on the carbon source media and simultaneously no growth on the control slant.

LIMITATIONS

MATERIALS REQUIRED BUT NOT PROVIDED

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

QUALITY CONTROL

Test Organisms Inoculation Method* Incubation Results
Basal Control:
Mycobacterium peregrinum
ATCC ® 14467
* 14 days No growth
Mycobacterium fortuitum
subsp. fortuitum
ATCC ® 6841

* 14 days No growth
Mycobacterium chelonae
ATCC ® 14472
* 14 days No growth
Mycobacterium neworleansense
Group III
ATCC ® 49404**

* 14 days No growth
Carbon Utilization with Inositol:
Mycobacterium neworleansense
Group III
ATCC ® 49404**

* 14 days Growth
Mycobacterium chelonae
ATCC ® 14472
* 14 days Partial to complete inhibition
Mycobacterium peregrinum
ATCC ® 14467**
* 14 days Partial to complete inhibition
Carbon Utilization with Mannitol:
Mycobacterium peregrinum
ATCC ® 14467**
* 14 days Growth
Mycobacterium chelonae
ATCC ® 14472**
* 14 days Partial to complete inhibition
Mycobacterium fortuitum
subsp. fortuitum
ATCC ® 6841

* 14 days Partial to complete inhibition
Carbon Utilization with Citrate:
Mycobacterium chelonae
ATCC ® 14472**
* 14 days Growth
Mycobacterium fortuitum
subsp. fortuitum
ATCC ® 6841**

* 14 days Partial to complete inhibition
Mycobacterium peregrinum
ATCC ® 14467
* 14 days Partial to complete inhibition

* Refer to the above "Procedure" section for a detailed explanation of the inoculation method.

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

User Quality Control

PHYSICAL APPEARANCE

Carbon Utilization Media should appear opaque and colorless.

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. Kubica, G.P., et al. 1985. Public Health Mycobacteriology: A Guide For The Level III Laboratory. Centers for Disease Control. Atlanta, GA.


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