RAPID ORNITHINE

Cat. no. K279

Rapid Ornithine, 15x103mm Tube, 1ml

20 tubes/box

INTENDED USE

Hardy Diagnostics Rapid Ornithine can be used to detect ornithine decarboxylase activity in as little as two to four hours. This test will assist in the identification of Enterobacteriaceae and Staphylococcus lugdunensis.

SUMMARY

Conventional methods for detecting ornithine decarboxylase activity require an extended period of incubation. The tests generally involve the fermentation of glucose which lowers the pH of the medium, to the optimum hydrogen ion concentration for decarboxylase activity. Decarboxylation results in the formation of amines that will raise the pH. Positive reactions are usually obtained after 18 to 24 hours of incubation, but some strains require up to four days incubation. An overlay of mineral oil acts as a barrier to oxygen and prevents alkalinization of the surface of the medium.

Fay and Barry modified the conventional decarboxylase medium by removing the glucose and decreasing the pH to 5.5.⁽⁷⁾ A small volume of the broth is heavily inoculated and then overlayed with sterile mineral oil. With the Hardy Diagnostics' Rapid Ornithine results can be obtained after only two to four hours of incubation at 35 to 37 degrees C.

The test can be used to determine ornithine decarboxylase activity in the family Enterobacteriaceae and can be used to differentiate Staphylococcus lugdunensis from other species of Staphylococcus. It is especially useful to differentiate Proteus mirabilis from other Proteus spp., which are ornithine decarboxylase negative.

Decarboxylase basal media consists of peptones and yeast extract which supply nitrogenous and other nutrients necessary for bacterial growth. Bromcresol purple is a pH indicator. The amino acid ornithine is added to detect the production of the enzyme ornithine decarboxylase.

FORMULA

Ingredients per liter of deionized water:*

L-Ornithine	10.0gm
Meat Peptone	5.0gm
Yeast Extract	3.0gm
Bromcresol Purple	1.0gm

Final pH 5.5 +/- 0.1 at 25 degrees C.

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

STORAGE AND SHELF LIFE

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

The expiration date applies to the product in its intact packaging when stored as directed.

This product has the following shelf life from the date of manufacture:

180 Days:

K279

Rapid Ornithine

Refer to the keyword "Storage", in the Hardy Diagnostics software program HUGO™, for more information on storing culture media.

PRECAUTIONS

Refer to the keyword "Precautions", in the Hardy Diagnostics software program HUGO™, for more information regarding general precautions when using culture media.

Refer to the keyword "MSDS", in the Hardy Diagnostics software program HUGO™, for more information on handling potentially hazardous material.

PROCEDURE

1. Inoculate a Rapid Ornithine tube with one to two colonies (18-24 hours old) and mix well.

2. Overlay with at least 0.5ml of sterile mineral oil (Cat. no. Z80).

3. Incubate aerobically at 35 to 37 degrees C., with tight caps, for two to four hours.

INTERPRETATION OF RESULTS

For reference, compare an uninoculated tube with inoculated tubes.

Positive reaction - development of a dark purple to violet color. Must be darker than the uninoculated reference tube.

Negative reaction - no development of color (remains pale yellow to light grayish-purple) or a development of yellow color.

Organisms expected to give a positive result:

• Edwardsiella spp.
• Enterobacter aerogenes
• Shigella sonnei
• Proteus mirabilis
• Staphylococcus lugdunensis

Organisms expected to give a negative result:

• Citrobacter freundii
• Shigella flexneri
• Klebsiella pneumoniae
• Proteus vulgaris
• Staphylococcus epidermidis
• all other Staphs are negative, except some rare strains of Staphylococcus epidermidis⁽⁵⁾

LIMITATIONS

It is recommended that biochemical and/or serological tests be performed on colonies from pure culture for complete identification.

Refer to the keyword "Limitations", in the Hardy Diagnostics software program HUGO™, for more information regarding general limitations on culture media.

MATERIALS REQUIRED BUT NOT PROVIDED

Standard microbiological supplies and equipment such as loops, swabs, applicator sticks, sterile mineral oil (Cat. no. Z80), other culture media, incinerators, and incubators, etc., as well as serological and biochemical reagents, are not provided.

QUALITY CONTROL

The following organisms are routinely used for testing at Hardy Diagnostics:

Test Organisms	Inoculation Method*	Incubation			Results
		Time	Temperature	Atmosphere
Staphylococcus lugdunensis ATCC® 49576	G	2-4hr	35°C	Aerobic	Positive
Proteus mirabilis ATCC® 12453	G	2-4hr	35°C	Aerobic	Positive
Staphylococcus epidermidis ATCC® 12228	G	2-4hr	35°C	Aerobic	Negative
Proteus vulgaris ATCC® 13315	G	2-4hr	35°C	Aerobic	Negative

REFERENCES

1. August, M.J., et al. 1990. Cumitech 3A; Quality Control and Quality Assurance Practices in Clinical Microbiology, Coordinating ed., A.S. Weissfeld. American Society for Microbiology, Washington, D.C.

2. Murray, P.R., et al. 2003. Manual of Clinical Microbiology, 8th ed. American Society for Microbiology, Washington, D.C.

3. Forbes, B.A., et al. 1998. Bailey and Scott's Diagnostic Microbiology, 10th ed. C.V. Mosby Company, St. Louis, MO.

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

5. Koneman, E.W., et al. 1997. Color Atlas and Textbook of Diagnostic Microbiology, 5th ed. J.B. Lippincott Company, Philadelphia, PA.

6. Quality Assurance for Commercially Prepared Microbiological Culture Media, M22-A2, Vol. 16, No. 16. 1996. Clinical Laboratory Standards Institute (CLSI - formerly NCCLS), Villanova, PA.

7. Fay, G.D and Barry, A.L. 1972. Rapid Ornithine Decarboxylase Test for the Identification of Enterobacteriaceae. Applied Microbiology; Vol. 23, p. 710-713.

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

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