CTA (CYSTINE TRYPTIC AGAR) MEDIA

Cat. no. Y10 CTA with Cellobiose, 13x100mm Tube, 3ml Deep 20 tubes/box
Cat. no. Y11 CTA Base, 13x100mm Tube, 3ml Deep 20 tubes/box
Cat. no. Y12 CTA with Dextrose, 13x100mm Tube, 3ml Deep 20 tubes/box
Cat. no. Y13 CTA with Lactose, 13x100mm Tube, 3ml Deep 20 tubes/box
Cat. no. Y14 CTA with Maltose, 13x100mm Tube, 3ml Deep 20 tubes/box
Cat. no. Y15 CTA with Mannitol, 13x100mm Tube, 3ml Deep 20 tubes/box
Cat. no. Y16 CTA with Sucrose, 13x100mm Tube, 3ml Deep 20 tubes/box
Cat. no. Y17 CTA with Sorbitol, 13x100mm Tube, 3ml Deep 20 tubes/box
Cat. no. Y18 CTA with Mannose, 13x100mm Tube, 3ml Deep 20 tubes/box
Cat. no. Y19 CTA with Xylose, 13x100mm Tube, 3ml Deep 20 tubes/box
Cat. no. Y20 CTA with Trehalose, 13x100mm Tube, 3ml Deep 20 tubes/box
Cat. no. Y24 CTA with Salicin, 13x100mm Tube, 3ml Deep 20 tubes/box

INTENDED USE

Hardy Diagnostics CTA Media are recommended for the determination of carbohydrate fermentation by fastidious organisms such as Neisseria spp. They are also used for the detection of bacterial motility and serve as a culture media for microorganism maintenance.

SUMMARY

Hardy Diagnostics CTA Media provide a nutritious basal medium composed of casein peptones, cystine, inorganic salts, phenol red, and agar. Necessary nutrients are supplied by the casein peptones and cystine. The inorganic salts serve as a source of essential ions. Phenol red is the pH indicator.

CTA Media supplemented with a 1% concentration of a specific carbohydrate are used to detect fermentation reactions. The 1% concentration is recommended to decrease the possibility of reversal reactions. Reversion occurs when the carbohydrate is depleted, thereby masking the acid by-products with alkaline by-products with peptone degradation. The acid produced by carbohydrate fermentation causes a decrease in pH, causing a color shift in the medium from red-pink to yellow.

The addition of agar to the medium allows for the detection of motility along the stab line of inoculation. Motile organisms extend from the stab line and produce turbidity or cloudiness throughout the medium. Non-motile organisms grow only along the stab line and leave the surrounding medium clear.

CTA Base (Cat. no. Y11) medium is a carbohydrate-free medium that can be used as a holding medium for fastidious microorganisms at 25ºC.

FORMULA

Ingredients per liter of deionized water:*

Pancreatic Digest of Casein 20.0gm
Sodium Chloride 5.0gm
L-Cystine 0.5gm
Sodium Sulfite 0.5gm
Phenol Red 17.0mg
Agar 3.5gm

Additionally, CTA Media with carbohydrate contain 10.0gm of the specified carbohydrate.

Final pH 7.5 +/- 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: Specimen collection is not applicable since this medium is not intended for primary isolation from clinical specimens. As a general rule, infectious material should be submitted directly to the laboratory without delay and protected from excessive heat and cold. If there is to be a delay in processing, the specimen should be inoculated onto an appropriate transport media and refrigerated until inoculation. Consult listed references for information on specimen collection. (1-5)

Method of Use:

1. Prior to inoculation, allow the medium to equilibrate to room temperature.

2. Using an inoculating needle, obtain isolated colonies from an 18-24 hour culture. Colonies should be taken from a non-selective primary medium, e.g. Chocolate Agar, (Cat. no. E14).

3. Inoculate the medium by stabbing the center of the medium at least seven times to a depth of 1/4 inch from the bottom of the tube.

4. Inoculate a control tube of CTA Base in parallel with the carbohydrate based media.

5. With caps loose, incubate aerobically at 35ºC. for 24-48 hours.

6. Examine daily for evidence of carbohydrate fermentation. To assist in acid by-product detection, the carbohydrate based media should be compared to the CTA Base control tube.

INTERPRETATION OF RESULTS

A positive carbohydrate fermentation reaction is the development of a yellow color change in the inoculated area (stab line) of the medium.

A negative carbohydrate fermentation reaction is demonstrated by a red-pink or deep red color in the medium. Growth with a deep red to orange color in the medium indicates that the carbohydrate has not been utilized and that peptone degradation has occurred.

Positive motility is denoted when turbidity or cloudy growth extends from the line of inoculation. Growth only along the stab line is indicative of a negative motility test.

LIMITATIONS

Only small amounts of acid may be produced by Neisseria spp., as the organisms utilize carbohydrates oxidatively.

Aerobic incubation is necessary, as incubation in CO 2 may lead to erroneous results.

Lack of sufficient inoculum may lead to erroneous results.

Do not inoculate to the bottom of the tube; improper inoculation may lead to weak acid reactions, thus creating difficulty in test interpretation.

Peptone utilization results in the production of alkaline by-products. Prolonged incubation may result in a reversion reaction where alkaline by-products mask the acid by-products formed from carbohydrate utilization.

Because some strains of meningococci, primarily sulfonamide-resistant strains, do not produce acid from maltose, repeated subcultures to non-inhibitory media may be required to restore their maltose-utilizing capability.

Some strains of gonococci require additional compounds not provided by the CTA Media formulations and will, therefore, not grow on CTA Media.

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
Time Temperature Atmosphere
CTA with Cellobiose:
Klebsiella pneumoniae
ATCC ® 13883
E 24-48hr 35°C Aerobic Growth; positive acid (yellow)
Morganella morganii
ATCC ® 25830
E 24-48hr 35°C Aerobic Growth; negative, no color change
CTA Base:
Neisseria meningitidis
ATCC ® 13090
E 24-48hr 35°C Aerobic Growth; negative, no color change
Neisseria gonorrhoeae
ATCC ® 43069
E 24-48hr 35°C Aerobic Growth; negative, no color change
CTA Dextrose :
Neisseria gonorrhoeae
ATCC ® 43069**
E 24-48hr 35°C Aerobic Growth; positive acid (yellow)
Neisseria meningitidis
ATCC ® 13090
E 24-48hr 35°C Aerobic Growth; positive acid (yellow)
Listeria monocytogenes
ATCC ® 19115
E 24-48hr 35°C Aerobic Growth; positive acid (yellow)
Moraxella catarrhalis
ATCC ® 25240
E 24-48hr 35°C Aerobic Growth; negative, no color change
CTA Lactose:
Neisseria lactamica
ATCC ® 23970**
E 24-48hr 35°C Aerobic Growth; positive acid (yellow)
Neisseria gonorrhoeae
ATCC ® 43069**
E 24-48hr 35°C Aerobic Growth; negative, no color change
Moraxella catarrhalis
ATCC ® 25240
E 24-48hr 35°C Aerobic Growth; negative, no color change
CTA Maltose:
Neisseria meningitidis
ATCC ® 13090**
E 24-48hr 35°C Aerobic Growth; positive acid (yellow)
Moraxella catarrhalis
ATCC ® 25240
E 24-48hr 35°C Aerobic Growth; negative, no color change
CTA Mannitol:
Enterococcus faecalis
ATCC ® 29212
E 24-48hr 35°C Aerobic Growth; positive acid (yellow)
Neisseria gonorrhoeae
ATCC ® 43069
E 24-48hr 35°C Aerobic Growth; negative, no color change
Moraxella catarrhalis
ATCC ® 25240
E 24-48hr 35°C Aerobic Growth; negative, no color change
CTA Mannose:
Klebsiella pneumoniae
ATCC ® 13883
E 24-48hr 35°C Aerobic Growth; positive acid (yellow)
Neisseria gonorrhoeae
ATCC ® 43069
E 24-48hr 35°C Aerobic Growth; negative, no color change
Moraxella catarrhalis
ATCC ® 25240
E 24-48hr 35°C Aerobic Growth; negative, no color change
CTA Salicin:
Enterococcus faecalis
ATCC ® 29212
E 24-48hr 35°C Aerobic Growth; positive acid (yellow)
Neisseria gonorrhoeae
ATCC ® 43069
E 24-48hr 35°C Aerobic Growth; negative, no color change
Moraxella catarrhalis
ATCC ® 25240
E 24-48hr 35°C Aerobic Growth; negative, no color change
CTA Sorbitol:
Listeria monocytogenes
ATCC ® 19115**
E 24-48hr 35°C Aerobic Growth; positive acid (yellow)
Moraxella catarrhalis
ATCC ® 25240
E 24-48hr 35°C Aerobic Growth; negative, no color change
CTA Sucrose:
Neisseria sicca
ATCC ® 9913
E 24-48hr 35°C Aerobic Growth; positive acid (yellow)
Neisseria gonorrhoeae
ATCC ® 43069**
E 24-48hr 35°C Aerobic Growth; negative, no color change
Moraxella catarrhalis
ATCC ® 25240
E 24-48hr 35°C Aerobic Growth; negative, no color change
CTA Xylose:
Klebsiella pneumoniae
ATCC ® 13883
E 24-48hr 35°C Aerobic Growth; positive acid (yellow)
Moraxella catarrhalis
ATCC ® 25240
E 24-48hr 35°C Aerobic Growth; negative, no color change
CTA with Trehalose:
Klebsiella pneumoniae
ATCC ® 13883
E 24-48hr 35°C Aerobic Growth; positive acid (yellow)
Boraxella catarrhalis
ATCC ® 25240
E 24-48hr 35°C Aerobic Growth; negative, no color change

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

User Quality Control

PHYSICAL APPEARANCE

CTA Media should appear clear, and red-pink in color.

N. gonorrhoeae growing in CTA Media

Neisseria gonorrhoeae (ATCC ® 43069) growing in CTA Media (Cat. no. Y12). Incubated aerobically for 24 hours at 35ºC.

B. catarrhalis growing in CTA Media

Moraxella catarrhalis (ATCC ® 25240) growing in CTA with Dextrose Media (Cat. no. Y12). Incubated aerobically for 24 hours at 35ºC.

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.


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