Inhibitory Mold Agar, Ulrich (Mold Inhibitory Agar, Ulrich)

Intended Use

Used for selective isolation of pathogenic fungi.

Composition**

Final pH ( at 25°C): 6.7±0.2

**Formula adjusted, standardized to suit performance parameters

Directions

Suspend 36.17 grams in 1000 ml purified/distilled water. Mix thoroughly and heat to boiling to dissolve the medium completely. Sterilize by autoclaving at ∆ 118 - 121°C for 15 minutes. Cool to 45-50°C. Mix well and pour into sterile Petri plates.

∆ corresponds to 12-15 lbs pressure.

Principle And Interpretation

Pathogenic fungi constitute a very small group among the vast number of organisms that belong to the Kingdom Fungi. Fungi with the potential to cause human diseases belong to the genera Aspergillus, Candida, Cryptococcus, Histoplasma and Pneumocystis. Members of pathogenic fungi group are scattered throughout four taxonomic classes based on their methods of reproduction viz. Zygomycetes, Basidiomycetes, Ascomycetes and Deuteromycetes (Fungi Imperfecti) (1). To confirm the existence and nature of infection by fungi and yeasts, direct methods are more important than indirect methods; identification of the organisms is much more useful than demonstrating the humoral and cellular responses of the host (2). Inhibitory Mould Agar formulated as per Ulrich (3) is used as a general-purpose medium for the selective isolation and cultivation of pathogenic fungi.

Tryptone and Peptone provide essential growth nutrients. Yeast extract is a rich source of vitamin B complex. Dextrose, starch and dextrin are energy sources for the metabolism of fungi. Sodium chloride and metallic salts provide essential ions and minerals. Chloramphenicol inhibits a wide variety of gram-positive and gram-negative bacteria. Potential contaminants of cosmetics and toiletries like Pseudomonas aeruginosa and Serratia marcescens are effectively inhibited by chloramphenicol. Sodium phosphates buffer the medium.

Type of specimen

Clinical samples - body fluids

Specimen Collection and Handling

For clinical samples follow appropriate techniques for handling specimens as per established guidelines (4,5). 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. Due to the coalescence of chloramphenicol in the media, the medium is not recommended for use in culturing sterile body fluids.

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 Amber coloured, clear to slightly opalescent gel forms in Petri plates.

Reaction Reaction of 3.62% w/v aqueous solution at 25°C. pH : 6.7±0.2

pH 6.50-6.90

Cultural Response Cultural characteristics observed after an incubation at 25-30°C for upto 7 days, Bacterial cultures are incubated at 35-37°C.

Key : * - Corresponding WDCM numbers.

Storage and Shelf Life

Store dehydrated and the prepared medium at 15-25°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. 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. Frey D., Oldfield R. J., Bridger R. C., A Colour Atlas of Pathogenic Fungi, Wolfe Medical Publications, London.
2. Cruikshank R., Marmion B. P., Duguid J. P., Swain R.H.A., (Eds.), Medical Microbiology, 12th Edition, Vol. II, Churchill Livingstone.
3. Ulrich J. A., 1956, Bact. Proc., S.A.B., M75: 87.
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.