TRANSGROW

Cat. no. X52 Transgrow, 50ml HardyFlask™, 12ml 20 flasks/box

INTENDED USE

Modified Martin Lewis is a selective medium used in qualitative procedures for the isolation of Neisseria gonorrhoeae with suppression of most other gram-negative diplococci, gram-negative bacilli, gram-positive organisms and yeast. The CO 2 enriched environment allows for the growth of pathogenic Neisseria spp.

SUMMARY

Thayer and Martin (1964) reported an improvement of the Chocolate Agar formulation by the addition of antimicrobics which suppressed the growth of some contaminating organisms but which allowed N. gonorrhoeae and N. meningitidis to grow. In 1970, trimethoprim lactate was shown to be of value in the suppression of Proteus spp. Martin and Lester modified Thayer-Martin Agar by increasing the dextrose concentration for transport, in addition to adding trimethoprim lactate. Martin and Lewis further improved the ability of the medium to inhibit Candida albicans by substituting anisomycin for nystatin. Because of the growing number of vancomycin strains of N. gonorrhoeae , the vancomycin concentration was reduced to 3mcg/ml, which resulted in the current formula for Modified Martin-Lewis Media. Hardy Diagnostics Transgrow incorporates adequate CO 2 within the media bottle to provide an enriched atmosphere for the recovery of pathogenic Neisseria spp. (6)

FORMULA

Ingredients per liter of deionized water:*

Proteose Peptone No. 3 15.0gm
Hemoglobin, Bovine 10.0gm
Sodium Chloride 5.0gm
Dipotassium Phosphate 4.0gm
Dextrose 1.5gm
Monopotassium Phosphate 1.0gm
Corn Starch 1.0gm
Anisomycin 10.0mg
Colistin 7.5mg
Trimethoprim Lactate 5.0mg
Vancomycin 3.0mg
KoEnzyme Enrichments 10.0ml
Agar 12.0gm

Final pH 7.3 +/- 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. 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: If the bottle is to be sent to a laboratory after inoculation, incubate them under appropriate conditions before shipment. Specimens should be submitted directly to the laboratory without delay and protected from excessive heat and cold. Specimens must be transported at ambient temperatures (15-30ºC.). Do not refrigerate.

Method of Use: Bring media to room temperature before use. Remove the cap while holding the bottle in the upright position. The bottle must always be held in the upright position when the cap is off. The CO 2 gas, which is necessary for growth, is heavier than air and will leak out of the bottle if it is tilted. Inoculate media by swabbing the surface from side to side (starting at the bottom) while rolling in a large "z" pattern to sufficiently transfer the specimen. Recap the bottle immediately. Do not leave the cap off any longer than necessary. Incubate at 35ºC. for 24-48 hours. Some strains may require up to 72 hours to appear.

INTERPRETATION OF RESULTS

Neisseria gonorrhoeae appears as small, grayish-white to colorless mucoid colonies. N. meningitidis forms similar colonies to N. gonorrhoeae , but larger and blue-gray.

An oxidase test may be performed from the primary medium for presumptive identification.

LIMITATIONS

This medium is intended for transport and primary isolation. Some diagnostic tests may be performed with the primary media. However, additional tests including gram stain and biochemical testing should be performed on pure cultures for complete identification. For more information, see appropriate references. (1-4)

The agents in selective media may inhibit some strains of desired species or permit the growth of species they were designed to inhibit. Therefore, specimens cultured on selective media should also be cultured on non-selective media to obtain additional information and to help insure recovery of potential pathogens. (1-3)

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
Neisseria gonorrhoeae
ATCC ® 43069
A 24-48hr 35°C CO 2 ** Growth
Neisseria gonorrhoeae
ATCC ® 19424
A 24-48hr 35°C CO 2 ** Growth
Neisseria meningitidis
ATCC ® 13090***
A 24-48hr 35°C CO 2 ** Growth
Staphylococcus epidermidis
ATCC ® 12228
B 24-48hr 35°C CO 2 ** Partial to complete inhibition
Proteus mirabilis
ATCC ® 43071
B 24-48hr 35°C CO 2 ** Partial to complete inhibition; no swarming
Escherichia coli
ATCC ® 25922***
B 24-48hr 35°C CO 2 ** Partial to complete inhibition
Candida albicans
ATCC ® 60193***
B 24-48hr 35°C CO 2 ** Partial to complete inhibition
Neisseria sicca
ATCC ® 9913***
B 24-48hr 35°C CO 2 ** Inhibited

User Quality Control

** CO 2 enriched atmosphere is generated within the bottle.

*** To be used only by commercial media manufacturers, according to NCCLS document M22-A.

PHYSICAL APPEARANCE

Transgrow should appear opaque, and brown in color.

N. gonorrhoeae growing on Transgrow

Neisseria gonorrhoeae (ATCC ® 43069) colonies growing on Transgrow (Cat. no. X52). Incubated in CO 2 for 48 hours at 35ºC.

S. epidermidis inhibited on Transgrow

Staphylococcus epidermidis (ATCC ® 12228) growth inhibited on Transgrow (Cat. no. X52). Incubated in CO 2 for 48 hours at 35ºC.

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. 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.

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

6. Potter, L.D., et al. 1983. Ammonium bicarbonate as a replacement for carbon dioxide in Transgrow bottles for primary isolation of Neisseria gonorrhoeae. J. Clin. Microbiol.; 18:1258-1259.


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

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