LABORATORY PROCEDURES FOR IDENTIFICATION OF FUNGI

Question 1

Temporary mounts;

Answer 1

1. KOH, 10-20%
2. lactophenol cotton blue (Aman medium)
3. India ink or nigrosine
4. Calcofluor white stain

Question 2

Rapid method for detection of fungal elements in clinical material; gentle heat increases rate of clearing, enables better visualization of fungal elements; dissolves keratin

Answer 2

KOH, 20-10%

Question 3

Preserves and stains fungi (shades of blue_; contains lactic acid, phenol, aniline blue; excellent mounting medium for most fungi

Answer 3

Lactophenol cotton blue (Aman medium)

Question 4

Negative staining to demonstrate capsule of C. neoformans:

Answer 4

India ink or nigrosine

Question 5

Sharp delineation of fungal elements in clinical specimens by fluorescence microscopy; fluorochrome dye; binds to chitin in fungal cell wall

Answer 5

Calcofluor white stain

Question 6

Permanent stains;

Answer 6

1. PAS (Peroidic Acid Schiff) stain
2. Gram stain (Hucker modification)
3. Acid-fast stain (Kinyoun modification)
4. Giemsa, Gridley, PAS, GMS (Gomori methenamine silevr)
5. Acridine orange

Question 7

Primary isolation and maintenance pf cultures. Addition of thiamine enhances growth of dermatophytes

Answer 7

Sabouraud dextrose agar (SDA)

Question 8

SDA + Cyclohexamide + Chloramphenicol; Isolation of pathogenic fungi from contaminated material:

Answer 8

MYCOSEL/MYCOBIOTIC

Question 9

Isolation and maintenance of yeast phase of systemic fungi at 35C (Body temperature); Culture for Actinomyces:

Answer 9

Brain-heart infusion agar (BHI)

Question 10

Recovery of Blastomyces and Histoplasma; conversion of these organisms to yeast stage:

Answer 10

BHI agar with 10% sheep blood

Question 11

identification of Histoplasma, Blastomyces, Coccidioides

Answer 11

Yeast extract agar

Question 12

Indicator 9phenol red) medium for dermatophytes - most produce red color; most saprophytes, yeasts, and bacteria either do not grow or reproduce no color change

Answer 12

DTM (dermatophyte test medium)

Question 13

Stimulate chlamydospore production of C. albicans; stimulate fungal sporulation - use for slide culture

Answer 13

Cornmeal agar

Question 14

In cornmeal agar, add ___% glucose to differentiate T. rubrum from T. mentagrophytes by amount of pigment formation

Answer 14

1% glucose

Question 15

Presumptive identification of Candida species

Answer 15

Cornmeal agar with Tween 80 and trypan blue

Question 16

Species identification of aspergilli

Answer 16

Czapek’s agar

Question 17

In Birdseed agar (Staib medium), C. neoformans produces ________ pigment

Answer 17

Brown pigment

Question 18

Agar that differentiates M. audouinii (-) from M. camis (+)

Answer 18

Rice agar

Question 19

Separate T. mentagrophytes (rapid utilization) from T. rubrum (delayed or no utilization)

Answer 19

Urease test medium (modification of Christensen’s)

Question 20

Identification of C. albicans; very small inoculum from isolated yeast colony + serum or plasma

Answer 20

Germ tube test

Question 21

Rapid identification of C. neoformans:

Answer 21

L-DOPA ferric citrate test

Question 22

Observe for pink color; C. neoformans (+) control, C. albicans (-) control

Answer 22

Rapid urease tests

Question 23

Hair baiting test differentiates ____________ from ____________.

Answer 23

Hair baiting test differentiate T. mentagrophytes (+) from T. rubrum (-)

Question 24

Positive result of hair baiting test; presence of __________ of hair shaft:

Answer 24

presence of V-SHAPED PENETRATION of hair shaft

Question 25

Concentrated Merthiolate extract of mature fungus culture; microscopic immunodiffusion test with commercial antisera; serological confirmation for certain systemic fungi:

Answer 25

Exoantigen test