Soyabean Casein Digest Medium w/ Yeast Extract and Hemin w/o Dextrose (Tryptone Soya w/ Yeast Extract and Hemin w/o Dextrose)

Intended Use

A highly nutritious medium which supports luxuriant growth of fastidious bacteria.

Composition**

Final pH (at 25°C): 7.3±0.2

**Formula adjusted, standardized to suit performance parameters

Directions

Suspend 32.52 grams in 1000 ml purified/distilled water. Heat if necessary to dissolve the medium completely. Dispense into tubes or flasks as desired. Sterilize by autoclaving at 15 lbs pressure (121°C) for 15 minutes.

Principle And Interpretation

Soyabean Casein Digest Medium with Yeast Extract and Hemin is prepared according to the formulation of USP (1). It is a highly nutritious medium for cultivating fastidious bacteria. It can also be used as general, all-purpose cultivation medium (2,3).

Tryptone, Soya peptone and yeast extract supply nitrogenous and carbonaceous nutrients, trace ingredients and vitamin B complex for the growth of microorganisms. Hemin provides additional growth factors. Dipotassium hydrogen phosphate maintains buffering conditions in the medium.

Type of specimen

Pharmaceutical samples, Clinical samples - faeces, pus

Specimen Collection and Handling

For clinical samples, follow appropriate techniques for handling specimens as per established guidelines (1,2). For pharmaceutical samples, follow appropriate techniques for sample collection, processing as per pharmaceutical guidelines (5). After use, contaminated materials must be sterilized by autoclaving before discarding.

Warning and Precautions

In Vitro diagnostic Use. For professional 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

1. Individual organisms differ in their growth requirement and may show variable growth patterns on the medium.
2. Each lot of the medium has been tested for the organisms specified on the COA. It is recommended to users to validate the medium for any specific microorganism other than mentioned in the COA based on the user’s unique requirement.

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

Reaction: Reaction of 3.25% w/v aqueous solution at 25°C. pH : 7.3±0.2

pH: 7.10-7.50

Cultural Response

Cultural characteristics observed after an incubation at 35 - 37°C for 18 - 24 hours.

Storage and Shelf Life

Store between 10-30°C in a tightly closed container and the prepared medium at 15-30°C. Use before expiry date on the label. On opening, product should be properly stored dry, after tightly capping the bottle in order 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. 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 (4,5).

Reference

1. The United States Pharmacopoeia-National Formulatory (USP-NF), 2022.
2. MacFaddin J.F., 1985, Media for Isolation-Cultivation-Identification-Maintenance of Medical Bacteria, Vol. I, Williams and Wilkins, Baltimore.
3. Mashimo P. A. and Ellison S A., 1959, J. Bacteriol., 78:636.
4. Isenberg, H.D. Clinical Microbiology Procedures Handbook 2nd Edition.
5. 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.