Soyabean Casein Digest Broth w/ SPS (Tryptone Soya Broth w/SPS)

Intended Use

Recommended as a general purpose medium used for cultivation of a wide variety of microorganisms.

Composition**

Final pH ( at 25°C) 7.3±0.2

**Formula adjusted, standardized to suit performance parameters

Directions

Suspend 30.30 grams in 1000 ml purified/ distilled water. Heat if necessary to dissolve the medium completely. Sterilize by autoclaving at 15 lbs pressure (121°C) for 15 minutes. Mix well and dispense as desired.

Note: If any fibres are observed in the solution,it is recommended to filter the solution by using a 0.22 micron filter to eliminate the possibilty of presence of fibres.

Principle And Interpretation

Soyabean Casein Digest Medium is recommended by various pharmacopeias as a sterility testing and as a microbial limit testing medium (1, 2, 3). This medium is a highly nutritious medium used for cultivation of a wide variety of organisms (4). Bacteremia is a serious and often life-threatening clinical condition. An important diagnostic tool for this condition is to analyze a blood specimen for the growth of bacteria on selected growth media. Such media often contain SPS as an anticoagulant and as an inhibitor of the bacteriostatic and bactericidal effects of blood cells and plasma factors (5, 6).

The combination of tryptone and soya peptone makes the medium nutritious by providing nitrogenous and carbonaceous compounds, amino acids and long chain peptides for the growth of microorganisms. Dextrose serve as the carbohydrate source and dibasic potassium phosphate buffers the medium. Sodium chloride maintains the osmotic balance of the medium. SPS has the added advantage of annulling the natural bactericidal action of blood and is not inhibitory.

Type of specimen

Clinical samples - Blood

Specimen Collection and Handling

For clinical samples follow appropriate techniques for handling specimens as per established guidelines (7,8).

After use, contaminated materials must be sterilized by autoclaving before discarding.

Warning and Precautions

In Vitro diagnostic Use only. Read the label before opening the container. Wear protective gloves/protective clothing/eye protection/ face protection. Follow good microbiological lab practices while handling specimens and culture. Standard precautions as per established guidelines should be followed while handling clinical specimens. Safety guidelines may be referred in individual safety data sheets

Limitations

This medium is general purpose medium and may not support the growth of fastidious organisms.

Performance and Evaluation

Performance of the medium is expected when used as per the direction on the label within the expiry period when stored at recommended temperature.

Quality Control

Appearance Cream to yellow homogeneous free flowing powder

Colour and Clarity of prepared medium Light yellow coloured clear solution without any precipitate. pH of 3.0% w/v aqueous solution at 25°C .

pH 7.10-7.50

Cultural Response Cultural characteristics observed after an incubation at 30-35°C for <= 3days for Bacterial and at 20-25°C for <= 5 days for Fungal.

Sterility test Light yellow coloured clear solution without any precipitation or sedimentation at room temperature for 14 days.

Cultural Response

Key : * Corresponding WDCM numbers.

Storage and Shelf Life

Store between 10-30°C in a tightly closed container and the prepared medium at 2-8°C. Use before expiry date on the label. On opening, product should be properly stored dry, after tightly capping the bottle inorder to prevent lump formation due to the hygroscopic nature of the product. Improper storage of the product may lead to lump formation. Store in dry ventilated area protected from extremes of temperature and sources of ignition Seal the container tightly after use. Use before expiry date on the label. Product performance is best if used within stated expiry period.

Disposal

User must ensure safe disposal by autoclaving and/or incineration of used or unusable preparations of this product. Follow established laboratory procedures in disposing of infectious materials and material that comes into contact with clinical sample must be decontaminated and disposed of in accordance with current laboratory techniques (7,8).

References

1. MacFaddin J. F., 1985, Media for Isolation-Cultivation-Identification-Maintenance of Medical Bacteria, Vol. 1, Williams & Wilkins, Baltimore, M.d.
2. The United States Pharmacopeia, 2008, USP31/NF26, The United States Pharmacopeial Convention, Rockville, MD.
3. Indian Pharmacopeia, 2007, Govt. of India, Ministry of Health and Family Welfare, New Delhi, India.
4. Forbes B. A., Sahm D. F. and Weissfeld A. S., 1998, Bailey & Scotts Diagnostic Microbiology, 10th Ed., Mosby, Inc. St. Louis, Mo.
5. Belding, M. E., and S. J. Klebanoff. 1972. Effect of sodium polyanethol sulfonate on antimicrobial systems in blood. Appl. Microbiol. 24:691-698.
6. Eng, J. 1975. Effect of sodium polyanethol sulfonate in blood cultures. J. Clin. Microbiol. 1:119-123.
7. Isenberg, H.D. Clinical Microbiology Procedures Handbook. 2nd Edition.
8. Jorgensen,J.H., Pfaller , M.A., Carroll, K.C., Funke, G., Landry, M.L., Richter, S.S and Warnock., D.W. (2015) Manual of Clinical Microbiology, 11th Edition. Vol. 1.