Fungal Agar (Mycological Agar)

Intended Use

For cultivation and maintenance of fungi.

Composition

**Formula adjusted, standardized to suit performance parameters

Directions

Suspend 35 grams in 1000 ml purified / distilled water. Heat, to boiling, to dissolve the medium completely. Sterilize by autoclaving at 15 lbs pressure (121°C) for 15 minutes. Cool to 45-50°C. Mix well and pour into sterile Petri plates. For preparing selective media, acidify the media upto pH 3.0-4.0 by the addition of two vials of 10% Lactic Acid Solution (FD095).

Principle And Interpretation

Mycological media are basal media to which antifungal agents may be added for checking their effect on fungi or bacteria to render them selective for isolation and cultivation of fungi. Mycological Agar is used while working with pathogenic fungi. Earlier media for fungi generally relied on an acidic pH to make the media less suitable for the growth of many bacteria (1). Fungal Agar is prepared according to the formulation suggested by Huppert and Walker (2).

Soya peptone in the medium provides nitrogen, vitamins and minerals necessary to support bacterial growth. Dextrose is a carbon source required for the growth of fungi. The pH may be adjusted to 4.0 after autoclaving by adding sterile 10% lactic acid sodium (FD195)/acetic acid and used for determining yeast and mould counts of carbonated beverages and food products (3).

Type of specimen

Clinical samples - nail scrappings, skin scrapings, etc.; Food samples.

Specimen Collection and Handling

For clinical samples follow appropriate techniques for handling specimens as per established guidelines (4,5).

For food samples, follow appropriate techniques for sample collection and processing as per guidelines (6).

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

• Individual organisms differ in their growth requirement and may show variable growth patterns on the medium.
• 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

Gelling

Firm, comparable with 1.5% Agar gel

Colour and Clarity of prepared medium

Light amber coloured, clear to slightly opalescent gel forms in Petri plates

Reaction

Reaction of 3.5% w/v aqueous solution at 25°C. pH: 7.0±0.2

pH

6.80-7.20

Cultural Response

Cultural characteristics observed after an incubation at 25 - 30°C for 48 - 72 hours (For Trichophyton species longer incubation may be required for upto 7days).

Growth Promotion

Key: *Corresponding WDCM numbers. # - Formerly known as Aspergillus niger

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 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. A. J. Clin. Path., 1951, 21: 684.
2. Huppert M., and Walker L. J., 1958, Am. J. Clin. Pathol., 29:291
3. Speck M. L., (Eds.), 1984, Compendium of Methods for the Microbiological Examination of Foods, 2nd Ed., APHA, Washington, D.C.
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.
6. Salfinger Y., and Tortorello M.L., 2015, Compendium of Methods for the Microbiological Examination of Foods, 5th Ed., American Public Health Association, Washington, D.C.