WILKINS CHALGREN AGAR

Technical Data #1991a / 2013.01.06

Wilkins Chalgren Agar is an enriched non selective solid medium used for cultivation and isolation of anaerobes and for susceptibility testing of anaerobic bacteria. The sterile pour filled tube is used in determining MIC of antibiotics for anaerobes by agar dilution method. Hemin and vitamin K1 enrichments enhance the growth of anaerobes.

 


 

FORMULA
in grams per liter purified filtered water

Casein Peptone

10,0

Gelatin Peptone

10,0

Yeast Extract

5,0

Dextrose

1,0

Sodium Chloride

5,0

L-Arginine

1,0

Sodium Pyruvate

1,0

Hemin

0,005

Vitamin K1

0,0005

Agar

15,0

pH 7.1 +/- 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 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 or deterioration (shrinking, cracking, evaporation or discoloration). Do not use dehydrated media if it is caked.


DIRECTIONS
Suspend 48 g of dehydrated media in 1000 ml of purified filtered water. Heat with frequent agitation and boil for one minute. Sterilize at 121 C for 15 minutes. Cool to 45-50 C. Mix gently and dispense into sterile Petri dishes or 18 ml into a sterile culture tube. Let it stand in an upright position. Melt each tube, cool down to 45-50 C, add the required antibiotic and pour into Petri plate immediately.


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

  1. Inoculate plate with the antibiotic disk.
  2. Incubate at 35 C under anaerobic conditions for 48 hours.


QUALITY CONTROL

Results after 48 hrs at 35C Anaerobic Atmosphere

Organisms

ATCC

Growth

Bacteroides fragilis

25285

+

Clostridium perfringens

13124

+

Fusobacterium nucleatum

25586

+

Peptostreptococcus anaerobius

27337

+


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. N.C.C.L.S. 1993 Methods for antimicrobial susceptibility testing of anaerobic bacteria Approved standard M11-A3 NCCLS Villanova, PA
  3. Sutter, V.L., D.M. Citron, M.A.C. Edelstein, S.M. Finegold Wadsworth Anaerobic Bacteriology Manual 4th ed C.V. Mosby St. Louis
  4. Wilkens, T.D., S.L. Chalgren, F. Jimenez-Ulate, C.R. Drake Jr., J.L. Johnson 1976 Inhibition of Bacteroides fragilis on blood agar plates and reversal of inhibition by added hemin. J. Clin. Microbiol. 3:359-363.


CATALOGUE NUMBERS

Dehydrated media 500 g QB-39-5502
     
Prepared media    
Plates, 100x15 mm 10/pkg 1991
Tubes, 20x125 mm, 18 ml 10/pkg 2131

 


 





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