MRSA BLUE AGAR

Technical Data #1797a / 2004.10.12

MRSA Blue Agar is a solid selective medium used for the detection of methicillin resistant Staphylococcus aureus from routine specimens specially from rectal swabs.


FORMULA
in grams per liter purified filtered water

Gelatin Peptone

11,8

Yeast Extract

9,0

D-Mannitol

10,0

Sodium Chloride

55,0

Lithium Chloride

5,0

Aniline Blue

0,2

Agar

13,5

Antibiotics

 

Oxacillin

0,002

Polymixin B

50 000,0 units

 

pH 7,2 +/- 0,2 25 C

This approximate formula may be adjusted and/or enriched to obtain best results.


PRECAUTIONS
This medium is for laboratory use only.


STORAGE
Store prepared media at 2-8 C protected from direct light.


SIGN OF DETERIORATION
Media should not be used if the expiry date has passed and if there are signs of contamination or deterioration (shrinking, cracking, evaporation or discoloration).


PROCEDURE
Prior to inoculate, the prepared media should be brought to room temperature.

  1. Directly, inoculate surface of the plates with specimen and streak to obtain isolated colonies.
  2. Incubate at 35 C for 24 hours.
  3. Re-incubate, negative plates for another 24 hours.


QUALITY CONTROL

Results after 24 hrs at 35C

Organisms

ATCC

Growth

Staphylococcus aureus

25923

-

Staphylococcus aureus

29213

-

Staphylococcus aureus

43300

+ blue

Staphylococcus aureus MRSA

clinical strain

+ blue


LIMITATIONS OF METHOD
This medium is only a part of the identification.
Other tests may be required.


REFERENCES

  1. Baker, C.N., C. Thornsberry, R.W. Hawkinson. 1983 Inoculum standardization in antimicrobial susceptibility testing: evaluation of overnight agar cultures and the rapid inoculum standardization system. 17:450-457.
  2. Lally, R.T., M.N. Ederer, B.F. Woolfrey 1985 Evaluation of Mannitol Salt Agar with Oxacillin as a Screening Medium for Methicillin-Resistant Staphylococcus aureus. J. Clin. Microbiol. 22:501-504.
  3. La Zonby, J.G., M.J. Starzyk 1986 Screening Method for Recovery of Methicillin-Resistant Staphylococcus aureus from Primary Plates J. Clin. Microbiol. 24:186-188


CATALOGUE NUMBERS

Dehydrated media

500g

QB-39-2821

 

 

 

Supplement

 

 

(Use 5 ml per 500 ml of medium)
Oxacillin 1 mg
Polymixin 25 000 IU

10 x 5 ml

8756

 

 

 

Prepared media

 

 

Plates, 100x15 mm

10/pkg

1797


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