OXFORD LISTERIA AGAR

Technical Data #1528a / 2013.05.20

Oxford Listeria Agar supplemented with antibiotics is used for the selective isolation of Listeria monocytogenes from foods. Esculin hydrolysed by the Listeria sp. strains give black colonies. Antibiotics and lithium chloride are the inhibitors of gram-positve and gram-negative bacteria.

 


 

FORMULA
in grams per liter purified filtered water

Casein Peptone

10,0

Meat Peptone

5,0

Heart Peptone

3,0

Yeast Extract

5,0

Sodium Chloride

5,0

Corn Starch

1,0

Esculin

1,0

Ferric Ammonium Citrate

0,5

Lithium Chloride

15,0

Agar

15,5

Supplement

 

Oxford

10 ml

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 IN VITRO diagnostic use only.


STORAGE
Store prepared media at 2-8 C protected from direct light and dehydrated powder, in a dry place in tightly-sealed containers at 2-25 C.


SIGN OF DETERIORATION
Media should not be used if the expiry date has passed. Prepared media should not be used if there are signs of contamination (shrinking, cracking, evaporation or discoloration). Do not use dehydrated media if it is caked.


DIRECTIONS
Suspend 61 g in 1000 ml of purified water. Heat with frequent agitation and boil for one minute. Sterilize at 121 C for 15 minutes. Cool to 45-50 C. Add 10 ml of Oxford Medium Supplement (#8716). Mix thouroughly and dispense into Petri dishes.


PROCEDURE
Bring prepared medium at room temperature before inoculation.

  1. Directly, inoculate the specimen and streak for isolated colonies.
  2. Incubate at 35 C for 24-48 hours.


QUALITY CONTROL

Expected results after 24 hrs at 35C

Organisms

ATCC

Growth

Listeria monocytogenes

15313

+ black colonies

Staphylococcus aureus

25923

- or partial

Escherichia coli

25922

- or partial


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


REFERENCES

  1. Lennette, E.H., Ballows, A., Hausler, W.J.Jr., and Shadomy, H.J. Manual of Clinical Microbiology. 4th ed. 1985 Washington D.C.: American Society for Microbiology.
  2. Mc Clain, D., W.H. Lee 1989 U.S. Department of Agriculture Food Safety Inspection Service, laboratory communication no 57, May 24, Microbiology Division, Beltsville, MD
  3. Mac Faddin, Jean F. 1985 Media for Isolation-Cultivation-Identification-Maintenance of Medical Bacteria. Vol. I, Baltimore, MD.: Williams & Wilkins.


CATALOGUE NUMBERS

Dehydrated media 500 g QB-39-3508
     
Oxford Supplement, 10x5 ml 10/pkg 8716
Modified Oxford Supplement, 10x5 ml 10/pkg 8717
     
Prepared media    
Plates, 100x15 mm 10/pkg 1528
Mono-Plates, 100x15 mm 10/pkg 1528M

 


 

 

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