S.F. (STREPTOCOCCUS FAECALIS) BROTH

Technical Data #2549a / 2000.11.01

S.F. Broth is a selective liquid medium used for identification and differentiation of Group D Enterococcus sp. from other streptococci. Sodium azide inhibits streptococci growth. Sugar fermentation changes the indicator, bromcresol purple, from purple to yellow.

 

FORMULA
in grams per liter purified filtered water

 

Casein Peptone

20,0
Dextrose

5,0
Potassium Phosphate, dibasic

4,0
Potassium Phosphate, monobasic

1,5
Sodium Chloride

5,0
Sodium Azide

0,5
Bromcresol Purple

0,032

pH 6,9 +/- 0,2 at 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 2-8° 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, evaporation or discoloration. Do not use dehydrated media if it is caked.


DIRECTIONS
Suspend 36 g of dehydrated media in 1000 ml of purified filtered water. Heat with frequent agitation and boil for one minute. Mix gently and dispense into culture tubes. Sterilize at 121° C for 15 minutes.


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

  1. Inoculate with 3-4 similar colonies from an overnight growth.
  2. Incubate at 35° C for 24 hours.


QUALITY CONTROL
Results after 24 hrs at 35ºC

 

Organisms

ATCC

Growth
Enterococcus faecalis

29212

+Acid
Streptococcus faecium

clinical

+Acid
Streptococcus bovis

clinical

-
Escherichia coli

25922

-

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


REFERENCES

  1. Bailey, R.W., E.G. Scott 1966 Diagnostic Microbiology, 2nd ed. St. Louis: The C.V. Mosby Company
  2. Hajna, A.A., C.A. Perry 1943 Comparative study of presumptive and confirmative media for bacteria of the coliform and for fecal streptococci. Am. J. Public Health 33:550.
  3. Mac Faddin, Jean F., Media for Isolation-Cultivation-Identification-Maintenance of Medical Bacteria Vol.1 1985 Baltimore, MD. Williams & Wilkins


CATALOGUE NUMBERS 

Dehydrated media 500 grams QB-39-3725
     
Prepared media    
Tubes, 16x125 mm, 5 ml 10/pkg 2549