TETRATHIONATE BROTH

Technical Data #2481a / 2014.12.11

Tetrathionate Broth with addition of iodide solution, is a selective enrichment medium used for cultivation of Salmonella sp. from feces, urine and foods. Bile salts inhibit gram-positive bacteria. Addition of iodide solution inhibits the normal intestinal flora.

 


 

FORMULA
in grams per liter purified filtered water

Casein Peptone

2,5

Meat Peptone

2,5

Bile Salts

1,0

Calcium Carbonate

10,0

Sodium Thiosulfate

30,0

 

pH 8,4 +/- 0,2 à 25º 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 2-8º 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. 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 46 g of dehydrated media in 1000 ml of purified filtered water. Heat with frequent agitation and boil for one minute. Cool to 45-50º C. Add 20 ml of a solution Iodine-Iodide Potassium (Iodine 6 g, Potassium Iodide 5 g in 20 ml of purified water). Mix gently and dispense into sterile culture tubes. Use the same day.


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

  1. Inoculate tubes with specimens. Stools should be emulsified into the broth before incubation.
  2. Incubate at 35º C for 24 hours with loosened caps.
  3. Subculture a few drops onto selective media for isolation of pathogens. Incubate at 35º C for another 24 hours.


QUALITY CONTROL

Results after 24 hrs at 35ºC

Organisms

ATCC

Growth

Shigella sonnei

9290

+

Salmonella typhimurium

14028

+

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., A. Balows, W.J. Hausler Jr., H.J. Shadomy 1985 Manual of Clinical Microbiology 4th ed. American Society for Microbiology, Washington, D.C.
  2. Mac Faddin, Jean F., 1985 Media for Isolation-Cultivation-Identification-Maintenance of Medical Bacteria. Vol.1. Baltimore, MD.: Williams & Wilkins.
  3. Speck, M.L. 1976 Compendium of Methods for the Microbiological Examination of Foods. Washington, D.C.: American Public Health Association.


CATALOGUE NUMBERS

Dehydrated media

500 g

QB-39-4606

 

 

 

Prepared media

 

 

Tubes 16x125 mm, 10 ml

10/pkg

2481

 


 

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