Fungal Culture Purpose, Procedure, Results and more
A fungal culture is a procedure used to determine if fungi are present in an area of the body. Fungi are microorganisms that thrive in damp, dark places, such as shoes, damp changing rooms, or skin folds. Some types of fungus are harmless, while others can cause infections.
Why to get Tested:
- To detect a fungal infection
- To determine which specific fungus or fungi are present
- To help guide treatment of Fungle Infactions
When to get Fungal Test:
- When a health care practitioner suspects that you have a skin, lung, or systemic fungal infection
- Sometimes after treatment to monitor its effectiveness.
Test Preparation Needed?
No need any preparation for this test
Sample Required:
A fungal culture might also be called a “fungal smear.” It can be used to test various areas of the body, including:
- Blood
- Cerebrospinal fluid (CSF)
- Pus
- Urine,
- Tissues
- Sputum
- Bronchoscopy lavage
- Pleural Fluid
- Pericardial Fluid
- Peritoneal fluid
- Scrapings from skin
- Hair
- Nail clippings
- Oral specimens
- Vaginal
Common Fungal Culture Media:
| Fungal Culture Media | Essential ingredients | Intended use |
|---|---|---|
| Birdseed 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 |
| Corn meal agar/ Corn meal 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 Agar / Mycobiotic Agar | Papaic digest of soybean meal, dextrose, cycloheximide, chloramphenicol, agar | Highly selective medium; recommended for the isolation of pathogenic fungi from materials containing a large amount of fungal and bacterial flora. |
| Potato dextrose agar (PDA) | 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 (SDA) | Pancreatic digest of casein, glucose, agar | Growth and maintenance of clinically important fungal pathogens. |
| Ascospore Agar |
Symptoms of Fungal Infaction
- Symptoms of a superficial fungal infection:
- Symptoms of a systemic fungal infection:
1. Symptoms of a superficial fungal infection:
Superficial fungal infections rarely cause serious illness, but they can be uncomfortable and annoying. Symptoms of these types of infections can include:
- Redness of the skin
- Rash
- Skin itch
- Discharge or Drain
- White spots inside the mouth.
- Thick or brittle nails
- Discoloration of the skin or nails.
2. Symptoms of a systemic fungal infection:
Systemic infections are infections that develop internally and can affect the entire body. These infections tend to be more serious, especially for people with weakened immune systems. These are sometimes called opportunistic infections because they occur when a common fungus or bacteria takes over a body in a weakened state.
Symptoms of systemic fungal infections can include things like:
- Fever
- Muscle pain
- Headache
- Shaking chills
- Nausea
Risks and side effects of this test:
The risks and side effects of mushroom cultures are minimal. You may have some discomfort during a swab or sputum culture, and a blood culture draw may leave you with some pain and bruising where the vein was accessed.
Otherwise, the greatest risk may come from a skin scrape, but it could cause minor bleeding, pain, or swelling for a short time after the test is done.
Changes in your heart rate
Interpretation of positive cultures of Aspergillus, Candida and Penicillium spp.
| Specimen | Aspergillus | Candida | Penicillium |
| Blood | Rare, may be significant or laboratory contaminant | Pathogenic and requires treatment (rare exceptions related to skin colonisation) | Not significant, a laboratory contaminant |
| Venous catheter | Rare, may be significant or laboratory contaminant | Probably significant – bloodstream infection likely, possibly silent. | Not significant, a laboratory contaminant |
| Tissue | Significant, if confirmed by histology | Significant, if confirmed by histology | Significant, if confirmed by histology |
| Pus or sterile site aspiration | Significant | Significant | Rare, probably significant, could be laboratory contamination |
| CSF | Significant | Significant | Probably laboratory contamination |
| Urine | Rare, possibly significant | Usually not significant. In immunocompromised or intensive care may signal disseminated candidiasis | |
| Sputum, other respiratory samples | Often significant – allergic, chronic or invasive disease, especially if A. fumigatus | Rarely significant. | Not significant. Possibly significant in allergy. |
| Peritoneal discharge after surgery | Rare, probably laboratory contaminant | Often significant – Candida peritonitis | Rare, probably laboratory contaminant |
| CAPD fluid | Rare, possibly significant | Significant and serious | Rare, probably laboratory contaminant |
| Nails | Probably significant, if toenails. | Probably significant, if nail fold or clinical appearance is that of superficial white onychomycosis | Laboratory or skin contaminant |
| Ear swab | Probably significant, if A. niger. If A. fumigatus consider invasive otitis. | Probably significant | Laboratory or skin contaminant |
| Cornea scraping | Probably significant | Probably significant | Rare, probably laboratory contaminant |
Likely significance of isolates from a range of clinical samples
| Sample | Likely organisms isolated | Comments on significance |
|---|---|---|
| Skin | 1. Dermatophyte fungi 2. Neoscytalidium dimidiatum/hyalinum 3. Other moulds 4. Candida spp. 5. Other yeast | 1. Significant if isolated 2. Significant if isolated 3. Likely contaminants, unless as a result of disseminated infection, e.g., Fusarium spp. 4. Significant if seen on direct microscopy 5. Unlikely significance, unless as a result of disseminated infection, e.g., Trichosporon spp. NB: Malassezia furfur is a cause of pityriasis versicolor, but is unlikely to grow in culture |
| Hair | 1. Dermatophyte fungi | Significant if isolated, some scalp carriage of Trichophyton tonsurans reported |
| Nails | 1. Dermatophyte fungi 2. Neoscytalidium dimidiatum/ hyalinum 3. Scopulariopsis spp., Fusarium spp., Aspergillus spp., Acremonium spp.*, some rarer moulds 4. Candida spp 5. Rhodotorula spp. | 1. Significant if isolated 2. Significant if isolated 3. Significant if seen on direct microscopy and isolated in pure culture from several pieces of nail tissue in the absence of a dermatophyte 4. Significant if isolated from paronychia and seen on direct microscopy 5. Often isolated, rarely significant even if seen on microscopy |
| Mucous membrane Swab | 1. Yeast species 2. Dimorphic fungi | 1. May be significant if symptomatic and seen in large amounts by direct microscopy. Also common commensals. 2. Significant |
| Nasal swab / Nasal secretions | 1. Aspergillus spp. mucoraceous moulds 2. Candida spp. | 1. Aspergillus flavus is the most common cause of fungal sinusitis, mucoraceous moulds cause rhinocerebral mucormycosis in appropriate patient groups 2. Likely commensals |
| Ear swab | 1. Aspergillus niger, other Aspergillus spp., Scedosporium spp., Scopulariopsis spp. 2. Candida spp. | 1. Direct microscopy usually positive 2. Common commensals |
| Sub-cutaneous samples | 1. Madurella spp., Pyrenochaeta romeroi, Leptosphaeria spp. 2. Scedosporium spp., Acremonium spp. 3. Sporothrix schenckii 4. Cryptococcus spp. 5. Alternaria spp., Exophiala spp. | 1. Cause of dark grain eumycetoma 2. Common cause of pale grain eumycetoma and subcutaneous hyalohyphomycosis 3. Cause of sporotrichosis, tracks up lymphatic system 4. May result from disseminated infection 5. Cause of subcutaneous phaeohyphomycosis |
| Corneal tissue | 1. Fusarium spp., Aspergillus spp., Acremonium spp., Candida spp. 2. Lasiodiplodia, Curvularia, other yeast and mould | 1. Common causes of fungal keratitis, must be on inoculum site, ideally with positive direct microscopy 2. Rarer causes but significant if compliant with above |
| Vitreous / aqueous fluid | 1. Candida spp., Aspergillus spp., Fusarium spp., Acremonium spp. | 1. Usually significant, ensure on inoculum streak, confirmed by Positive direct microscopy |
| Sputum | 1. Candida spp. 2. Cryptococcus spp. 3. Aspergillus fumigatus, other Aspergillus spp.,Scedosporium spp. 4. Exophiala spp. | 1. Very rarely significant, commonly colonises airways, possible role in deteriorating lung function in CF and ABPM patients. Pulmonary candidosis is rare and usually a result of haematogenous dissemination. 2. Significant 3. May be significant in the appropriate host, common colonisers in CF patients and may contribute to deteriorating lung function 4. Common colonisers in CF patients and may contribute to deteriorating lung function |
| Bronchoalveolar lavage | 1. Aspergillus fumigatus, other Aspergillus spp.,Scedosporium spp. Cryptococcus spp. 2. Dimorphic fungi 3. Candida spp. | 1. Likely to be significant in appropriate host Significant 2. Significant 3. Commonly colonise airways—very rarely significant |
| Tissue biopsy | 1. Aspergillus spp., Candida spp., Cryptococcus spp., mucoraceous moulds, agents of yalohyphomycosis and phaeohyphomycosis 2. Dimorphic fungi | 1. Positive direct microscopy enhances significance and is proof of invasive fungal infection. Isolation in the absence of positive microscopy should not be dismissed without careful consideration 2. Significant |
| Bone marrow | 1. Histoplasma spp. and other dimorphic fungi, other yeast, Aspergillus spp | 1. Dimorphic fungi always significant, other yeast and Aspergilllus usually significant |
| Blood | 1. Candida spp., Cryptococcus spp. Trichosporon spp. Rhodotorula spp., Malassezia pachydermatis 2. Fusarium spp., Acremonium spp. , Paecilomyces spp., Purpureocillium spp., Scedosporium spp. 3. Dimorphic fungi | 1. Candidaemia is the most common deep fungal infection. Other yeast genera are seen causing fungaemia in mmunocompromised patients 2. Fusarium and Acremonium spp.* are the most common mould genera isolated from blood during disseminated infection Aspergillus spp. and other mould genera are usually contaminants 3. Dimorphic fungi are always significant |
| CSF | 1. Cryptococcus spp., Candida spp., other yeast species Aspergillus spp. 2. Dimorphic fungi | 1. Usually significant, antigen tests can help to confirm 2. Significant |
| Prostate fluid | 1. Dimorphic fungi, Cryptococcus spp. | 1. Significant |
| Peritoneal fluid | 1. Yeast isolates, Aspergillus, Paecilomyces | 1. Probably significant |
| Pleural fluid | 1. Cryptococcus spp., Coccidioides spp., Aspergillus spp. | 1. Cryptococcus spp. and Coccidiodes spp. may be found in pleural fluid following pulmonary infection, other dimorphic fungi are rare but significant if isolated. Aspergillus spp. are a rare but significant cause of pleural effusion |
| Joint fluids | 1. Candida spp., dimorphic fungi, Aspergillus fumigatus | 1. Significant |
| Pus from abscess | 1. Candida spp., Cryptococcus Spp., Sporothrix schenckii | 1. Significant |
| Urine (non-catheter) | Candida spp., dimorphic fungi, Aspergillus spp., Talaromyces marneffei, Trichosporon spp. | 1. Candida spp. are significant in symptomatic patients, other organisms are usually found in urine as a result of deep or disseminated infection |
References:
- American Society for Microbiology – Basic Mycology Techniques: https://www.asm.org/Basic-Mycology-Techniques
- Mycological Society of America – Guidelines for Growing Fungi: http://msafungi.org/guidelines-for-growing-fungi/
- International Mycological Institute – Fungal Culture Preservation Handbook: http://www.cabi.org/Uploads/File/IMI%20Handbook%20(2nd%20ed%20)-%20Culture%20Preservation.pdf
- NCBI – Fungal Culture Collections: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3042924/
- USDA – Fungal Culture Collections: https://www.ars.usda.gov/northeast-area/peoria-il/national-center-for-agricultural-utilization-research/mycotoxin-prevention-and-applied-microbiology-research/docs/fungal-culture-collections/
