LABORATORY DIAGNOSIS OF FUNGAL DISEASES

Saline Mount

[Microscopic Examination]

To observe hyphal elements

10% KOH

Rapid method for detection of fungi on hair, skin,
nails. Serves as clearing reagent to remove debris

10-15 mins (depending on the lab)

10% KOH clearing time?

Heat

_______ increases rate of clearing

40% DMSO

Used to increase the rate of clearing aside from heat

Lactophenol Cotton Blue

Also known as Aman Medium. Excellent mounting medium for most fungi. Most widely used stain. Contains lactic acid, phenol, and cotton blue (stain).

Calcofluor White Stain

A fluorescence stain.

Exhibits bluish-white or apple-green fluorescence depending on filter used.

Calcofluor White Stain

Stains chitin

India Ink

For the demonstration of encapsulated yeast (1 minute)

Periodic Acid Schiff

For differentiation of fungi in tissue scrapings

Gram Stain

(3 mins)
Hucker's Modification
Use of crystal violet and ammonium oxalate
Fungi is always gram-positive

Grocott Methenamine Silver

Best fungal stain for tissues

Black

In Grocott Methenamine Silver, fungi is stained ___

Acridine Orange

For tinea versicolor

Papanicolaou's stain

Used when suspecting Candida albicans in cervicovaginal smear

Masson Fontana

For demonstration of melanin pigment or pigmented
fungi

Saboraud Dextrose Agar

General purpose culture medium (pH 5.6)

Mycosel or Mycobiotic

Culture media that is commercially available. SDA with cycloheximide and chloramphenicol

TRUE

(True or False)
Mycosel or Mycobiotic are inhibitors

Cycloheximide

This antibiotic prevents growth of contaminating fungi (saphrophytic fungi)

Chloramphenicol

An anti-bacterial

Dermatophyte Test Medium

Allows growth of dermatophytes and to separate saprophytes and bacteria

Phenol red; red

Dermatophyte pH indicator: __________
Dermatophytes color: __________

Cornmeal Agar with 1% glucose

For Trichophyton rubrum and T. mentagrophytes; chlamydospore production

For pigment production

Positive (+)

Trichophyton rubrum result in Cornmeal Agar

Negative (-)

T. mentagrophytes result in Cornmeal Agar

Cornmeal Agar with Tween 80 and Tryphan blue

This culture media is for the presumptive identification of
Candida

BHI Blood Agar

Isolate and maintains yeast phase of systemic fungi

37C

BHI Blood Agar incubation

Czapeck's Agar

Culture media for Aspergillus

Birdseed Agar

Culture media for Cryptococcus

Cottonseed Medium

Culture media for Blastomyces

Rice Medium

Culture media for the identification of M. auduoinii and other Microsporum spp.

no growth (negative result)

M. auduoinii result in Rice Medium

positive result

Other Microsporum spp. result in Rice Medium

SABHI (Saboraud Brain Heart Infusion)

Culture media for the Recovery of Blastomyces and Histoplasma; Yeast conversion

Urease Test Medium

For differentiation of T. rubrum and T. mentagrophytes

Trichophyton Agars

Culture media contains casein (1-5) and ammonium nitrate (6-7)

Room temperature

Incubation temperature

30 days; 4 weeks

Culture held for ______ before reporting as negative. Or may be held for ______

40 mL of agar medium

Plates tend to dehydrate during prolonged incubation, prepare plated media at least how many mL of agar medium?

Increase

Since incubation takes long, we must (increase/decrease) the amount of volume of culture media or plate media?

Germ Tube Test

A test with the use of plasma/serum. Cost effective test to presumptively identify C. albicans. Incubation for 3-4 hrs. Observe for elongated structure (3-4x the length of yeast)

L-DOPA Ferric Citrate Test

A test for rapid identification of C. neoformans

C. neoformans, T. mentagrophytes

Positive in Urease Test

T. mentagrophytes

Positive in Hair Baiting Test

Exoantigen Test

Serologic test for systemic mycoses (dimorphic fungi)

Principle: Microscopic Immunodiffusion using commercial antisera

Exoantigen Test

Used to confirm identity of fungal isolates. Serologic confirmation: Detection of fungal antigens

Antigen Detection

Beta 1,3 glucan for yeast

CAD test for C. neoformans

CHO Utilization Test

For definitive ID of yeasts

Disk Diffusion, Broth Dilution, E-Test

AST (Antifungal Susceptibility Testing) Methods

Candida

CLSI M44-A2 (Disk Diffusion) is for ______

yeast

CLSI M27-A3 (Broth Dilution) is for ______

filamentous fungi

CLSI M38-A2 (Broth Dilution) is for _______