NITRATE BROTH WITH DURHAM TUBE NITRATE BROTH WITHOUT DURHAM TUBE

Technical Data #2056a / 2013.07.09

Nitrate Broth is a liquid medium used to determine the ability of microorganisms to reduce nitrate to nitrites or to free nitrogen gas. Nitrites are colorless; addition of sulfanilic acid and naphtylamine reagents, gives a positive reaction resulting in a red color. No change in color, means that nitrates are reduced to nitrogen or nitrates are still intact in the medium.

 


 

FORMULA
in grams per liter purified filtered water

Gelatin Peptone

5,0

Beef Extract

3,0

Potassium Nitrate

1,0

pH 7.0 +/- 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 (evaporation or discoloration). Do not use dehydrated media if it is caked.


DIRECTIONS
Suspend 9 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. Mix thouroughly and dispense into sterile culture tubes containing a Durham tube.


PROCEDURE
Bring prepared medium at room temperature before inoculation.

  1. Inoculate with 1-2 similar colonies from an overnight growth.
  2. Incubate at 35 C for 24-48 hours, with loosened caps.
  3. Add 0,5 ml (5-10 drops) of Sulfanilic Acid (8560) and 0,5 ml (5-10 drops) of Dimethylnaphtylamine (8559) Reagents. Note the results.

Positive result: red color
Negative result: no change in color.
Gas: present or absent


QUALITY CONTROL

Expected results after 24 hrs at 35C

Organisms

ATCC

Red Color

Gas

Escherichia coli

25922

+

+

Pseudomonas aeruginosa

27853

+

+

Acinetobacter calcoaceticus

19606

-

-


LIMITATIONS OF METHOD
Do not use in excess Zinc dust because this may result in false negative reaction or just a fleeting color. This is only a part of the identification. Others tests may be required.


REFERENCES

  1. Ewing, W.H., 1986 Edwards and Ewing's identification of Enterobacteriaceae 4th ed. Elsevier Science Publishing Co, New York
  2. Finegold, S.M., E.J. Baron 1986 Bailey and Scott's Diagnostic Microbiology 7th ed. C.V. Mosby St. Louis
  3. 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.
  4. 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-39-3306
     
Prepared media    
Tubes 16x125 mm, 5 ml 10/pkg 2056
w/ Durham tube, 5 ml 10/pkg 2941
w/ Durham tube, 7 ml 10/pkg 2916
     
Sulfanilic Acid 30 ml 8560
N,N,-Dimethyl-Naphtylamine 30 ml 8559

 


 

 

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