To ensure that clinical specimens are properly cultured, two types of media are required. The non-selective medium (e.g. Brain Heart Infusion Agar) should be used. Other media should be specific and tailored to isolate pathogenic fungi.
A battery of media is recommended for optimal fungal pathogen recovery.
- Cyclohexamide is mixed with media to prevent the growth of rapidly growing contaminating moulds.
- Media can be used with or without antibacterial agents (gentamicin, chloramphenicol and ciprofloxacin all are common antibacterial options).
To kill contaminating bacteria species, antibacterial agents can be used. Antibacterial media are not required if the sample is taken from an uncontaminated site.
Examples of Common Fungal Culture Media
|Fungal Culture Media||Essential ingredients||Intended use|
|Bird seed agar||Guizotia abyssinica seeds, glucose, creatinine, chloramphenicol, monopotassium phosphate, agar||Selective and differential isolation of Cryptococcus neoformans from clinical specimens.|
|Brain-heart infusion agar||Brain heart infusion, glucose, L-cysteine hydrochloride, agar||Growth of fastidious pathogenic fungi such as Histoplasma capsulatum and Blastomyces dermatitidis|
|CHROMagar Candida medium||Peptone, glucose, chloramphenicol, ‘Chromogenic ix’, agar||Selective and differential chromogenic medium for the isolation and identification of various Candida species|
|Cornmeal agar/ Cornmeal tween agar||Cornmeal, Tween 80, agar||Identification of C. albicans by microscopic morphology or chlamydospore production.|
|Czapek-Dox agar||NaNO3, K2HO4, KCl, MgSO4, FeSO4, glucose, agar||Identification of Aspergillus and Penicillium species. It can also be used for chlamydospore production by Candida albicans.|
|Dermatophyte test medium (DTM)||Soy peptone, dextrose, cycloheximide, chloramphenicol, gentamicin sulfate, phenol red, agar||Primary and differential fungal cultures medium to isolate and identify dermatophytes.|
|Inhibitory mold agar (IMA)||Tryptone, beef extract, yeast extract, starch, dextrin, chloramphenicol, gentamicin, and saline buffer||Primary recovery of pathogenic fungi exclusive of dermatophytes.|
|Mycosel/mycobiotic agar||Papaic digest of soybean meal, dextrose, cycloheximide, chloramphenicol, agar||Highly selective medium; recommended for isolation of pathogenic fungi from materials containing a large amount of fungal and bacterial flora|
|Potato dextrose agar||Potato extract, potato infusion, dextrose, agar||Ideal medium for slide culture preparation. It promotes sporulation of dermatophytes. Demonstration of pigment production by T. rubrum.|
|Potato flake agar||Potato flakes, dextrose, agar||Primary recovery of saprophytic and pathogenic fungi.|
|Rice starch agar||Cream of rice, Tween 80, agar||Production of chlamydospore in Candida albicans|
|Sabouraud dextrose agar||Pancreatic digest of casein, glucose, agar||Growth and maintenance of clinically important fungal pathogens.|
Brain-heart infusion (BHI) agar
It’s a non-selective fungal culture medium which allows the growth of almost all clinically relevant mushrooms. It is used to recover saprophytic and dimorphic fungal species.
Czapek dox agar
Czapekdox agar, a semisynthetic medium that contains sodium nitrate (the sole source of nitrogen), is a semisynthetic medium. It is used to subculture Aspergillus species in order to perform differential diagnosis.
Inhibitory mold agar (IMA)
An enriched medium containing chloramphenicol and some forms of gentamicin is called inhibitory mold agar (IMA). It is able to support the growth of many fungi. However, it may also inhibit bacterial growth due to its antibiotic properties. It is used to recover dimorphic pathogenic fungal species. It will not be used to recover dermatophytes and saprophytic fungi.
It is usually Sabouraud’s dextrose-agar with cycloheximide or chloramphenicol. It is used to recover dermatophytes.
Niger Seed Agar
It is used to identify Cryptococcus neoformans.
Potato Dextrose Agar (PDA)
Potato Dextrose Aggar (PDA), is a common media for fungal growth. It is made from an infusion potato and dextrose. To inhibit bacterial growth, it can be supplemented by acid or antibiotics. It is used for plate counting methods to test for bacteria in foods, dairy products, cosmetics, and other food items.
Sabouraud’s Heart Infusion (SABHI) agar
Primary recovery of dimorphic and saprophytic fungi, especially fastidious strains.
Sabouraud’s dextrose agar (SDA)
- Sabouraud’s Aggar is sufficient to recover dermatophytes in cutaneous samples or yeasts from genital culture.
- It is not recommended to be used as a primary isolation medium, especially because it is not rich enough to recover fastidious pathogenic species.
- Sabouraud’s dextrose-agar (2%) can be used as a medium to subculture fungi from enriched media. It is designed to increase sporulation and provide a more distinctive colony morphology.
Potato flake agar: Primary recovery of dimorphic and saprophytic fungi, especially fastidious and slow-growing varieties.