ANTIBIOTIC MEDIUM # 3 (PENASSAY BROTH)

Technical Data #2712a / 2006.04.13

Antibiotic Medium # 3 (Penassay Broth) is a liquid medium used for the determination potency of antibiotics by the microbial assay technique following the USP (United States Pharmacopeia) specifications.

 


 

FORMULA
in grams per liter purified filtered water

Gelatin Peptone

5,0

Yeast Extract

1,5

Beef Extract

1.5

Sodium Chloride

3,5

Dextrose

1,0

Potassium Phosphate, dibasic

3,68

Potassium Phosphate, monobasic

1,32

pH 7,0 +/- 0,2 à 25º 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 2-8º C protected from direct light and dehydrated powder, in a dry place in tightly-sealed containers at 2-25º C.


SIGN OF DETERIORATION
Media should not be used if the expiry date has passed. Do not use dehydrated media if it is caked.


DIRECTIONS
Suspend 17,5 g in 1000 ml of purified water. Heat with frequent agitation to dissolve completely. Dispense into culture tubes. Sterilize at 121º C for 15 minutes.


PROCEDURE
Bring prepared medium at room temperature before inoculation. Follow the references for the appropriate procedures.

  1. Wash the growth of a fresh slant agar with the Anibiotic Medium #3
  2. Dilute the broth as required
  3. Following the reference procedures, prepare working dilutions of the antibiotic reference standard in specific concentrations.
  4. Incubate tubes at 35º C for 3-4 hours and then stop the growth with a 0,5 ml of 1:3 diluted formalin
  5. Read with a suitable spectrophometer and compare the growth with the given reference standard solutions.


QUALITY CONTROL

Expected results after 24 hrs at 35ºC

Organisms

ATCC

GROWTH

Escherichia coli

25922

+

Klebsiella pneumoniae

13883

+

Staphylococcus aureus

6538

+


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


REFERENCES

  1. Bacteriological Analytical Manual, 6th, ed, 1984
  2. Assay Methods of Antibiotics, Grove, D.C. and W.A. Randall, Medical Encyclopedia inc. New York 1955
  3. The United States Pharmacopeia, 21st, ed Rev, United States Pharmacopeial Convention, Rockville, Md, 1985


CATALOGUE NUMBERS

Dehydrated media 500 grams QB-39-0137
     
Prepared media    
Tubes 16x125 mm, 10 ml 10/pkg 2712
Tubes 16x125 mm, 10 ml 10/cs 2712-H

 


 

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