| Organism | Microscopy | Culture and identification | Non-culture methods |
| General | Histopath PAS & silver stains etc.
K0H with Parker ink (skin scrapings/nails) |
SAB (Saborauds dextrose agar) medium +/- antibiotics +/- cycloheximide
For other media, see here. Blue thymol blue sticky tape preparation from cultures for examining hyphae and fruiting structures |
MALDI-TOF for ID
Invasive fungal disease: 1-3 Beta-D-Glucan assay (serum) – broad spectrum but not incl. Cryptococcus |
| Candida albicans and other similar species | Characteristic yeast shapes larger than bacteria; appear Gram positive | Colonies with ‘feet’ (C. albicans)
Chromogenic candida agar – usually sufficient for ID. Several types. Yeast sugar assimilation panels e.g. API , VITEK etc |
|
| C. neoformans
C. gattii |
India ink preparation for capsule (CSF)
NB. capsule production media dependent |
Presumptive: capsule+yeast= Cryptococcus (no other species has a capsule)
Urease positive Bird seed agar – pigmented colonies = Cryptococcus CGB medium- (L-Canavanine, glycine, 2 bromthymol blue agar) distinguishes C. gattii from C. neof. |
Crypto antigen lateral flow assay (serum/CSF)
IF serotyping of isolates- research only |
| Aspergillus species | Histopath – narrow septate hyphae; acute angle branching | Culture appearance- pigmentation
Species ID by sticky tape preparation |
Galactomannan EIA (serum, BAL)
Serum precipitins used in ABPA Dx
|
| Pneumocystis jirovecii(PJP) | Bronchial lavage / induced sputum – IF / silver / Giemsa stains | Usually a clinical diagnosis
No culturable
|
PCR more sensitive than IF |
Histopathologic Diagnosis of Fungal Infections in the 21st Century : excellent overview- invasive fungal infections are often recognised only by histopathologists post mortem! Also this slide set : https://www.slideshare.net/appyakshay/fungus-in-histopathology
Cryptococcal serum antigen screening for HIV positive patients– previous posting. This ICT has excellent sensitivity and specificity for crypto antigen detection.
India ink preparation Gram stain of Candida species
Microbiology and Infectious Diseases postgraduate teaching (PRIDA) 