Lab Diagnosis

Question 1

Reagent used to demonstrate FUNGAL HYPHAE

Answer 1

10% KOH

Question 2

Purpose of gentle heating using 10% KOH

Answer 2

Increase rate of clearing

Question 3

Most commonly used test/reagent in the Laboratory

Answer 3

Lactophenol Cotton Blue (LPCB)/Aman’s Medium

Question 4

Lactophenol Cotton Blue. Give the Components and its purpose for each

Answer 4

Lactic acid - preserves fungal structure
Phenol - killing agent
Aniline Blue - staining fungal structures

Question 5

Reagent used for Negative Staining

Answer 5

KOH with Fountain Pink

Question 6

True or False. Negative Staining Result
Pink - Fungal Structures
Colorless - Fungal Organism

Answer 6

False.
Pink - Fungal Organism
Colorless - Fungal Structures

Question 7

Test used to detect infection of the hair or scalp, which organisms glow that would help locate the infected area

Answer 7

Wood Lamp Illumination Method

Question 8

Detects Candida Infection/Thrush

Answer 8

Saliva/Spit Test

Question 9

Positive Result in Saliva Test

Answer 9

Strings of the saliva resembling a jellyfish and a cloudy saliva at the bottom of glass with cloudy specs.

Question 10

Result of India Ink Method

Answer 10

Positive: Fungal organism take up the stain in a dark background and transparent capsule surrounding the organism.

Question 11

Frequently added component in culture media

Answer 11

Chloramphenicol - inhibits growth of bacteria

Cycloheximide - inhibits growth of saprophytic fungi.

Question 12

This allows growth of fastidious dimorphic fungi

Answer 12

5-10% SRBCs

Question 13

General medium for isolation of Fungi

Answer 13

SDA - Saborauds Dextrose Agar

Question 14

Screening Medium for Dermatophytes

Answer 14

DTM - Dermatophytes Test Medium

Question 15

Positive Result in DTM

Answer 15

Red color change from Amber

Question 16

Indicator used in DTM

Answer 16

Phenol Red

Question 17

Culture media to recover Blastomyces and Hiostoplasma

Answer 17

Sauboraud BHI

Question 18

BHIA

Answer 18

used to recover DIMORPHIC fungi

Question 19

Added agent in SDA to enhance growth recovery of dermatophytes

Answer 19

Thiamine

Question 20

Demonstrate Pigment production

Answer 20

PDA

Question 21

Demonstrate for Chlamydospore production

Answer 21

Cornmeal Agar

Question 22

Media used for presumptive identification of Candida species

Answer 22

Cornmeal Agar with Tween 80 & Trypan Blue

Question 23

Used for differentiation of Aspergillus species

Answer 23

Czapek’s Agar

Question 24

Birdseed Agar

Answer 24

Identification of Cryptococcus neoformans

Question 25

Pigment produced by C. neoformans in Birdseed agar that indicates presence of Phenol oxidase

Answer 25

Brown Pigment

Question 26

True or False. Rice Agar: Differentiates Trichophyton mentagrophytes from Trichophyton rubrum Urease Agar/Test Medium: Differentiates Microsporum audonii and Microsporum canis.

Answer 26

False. Urease Agar/Test Medium: Differentiates Trichophyton mentagrophytes from Trichophyton rubrum Rice Agar: Differentiates Microsporum audonii and Microsporum canis.

Question 27

Result to Differentiate Tricophyton

Answer 27

Trycophyton mentagrophytes - Rapid utilization | Trycophytoin rubrum - Late utilization

Question 28

Result to Differentiate Microsporum

Answer 28

Microsporum audonii - Negative | Microsporum canis - Positive

Question 29

Standard method for Microslide Culture Technique

Answer 29

Ridell Culture Method

Question 30

Modified Ridell Method

Answer 30

Remel Culture Method

Question 31

This method contains two plastic molded blocks containing sporulating agar.

Answer 31

Remel Culture Method

Question 32

Incubation of Culture in Incubator

Answer 32

30C

Question 33

Incubation of Culture in Room Temp.

Answer 33

25C

Question 34

Maximum incubation period

Answer 34

4 weeks

Question 35

Incubation period for Candida Infections

Answer 35

5 days

Question 36

8 weeks

Answer 36

Incubation for Dimorphic fungi and before it is reported as negative

Question 37

A special test used for identification of Trycophyton mentagrohytes

Answer 37

Hair perforation Test

Question 38

Special test for identification of C. albicans

Answer 38

Germ Tube Test

Question 39

Specimen used in Germ Tube Test

Answer 39

Serum or Fetal Bovine serum

Question 40

Results in Germ Tube Test

Answer 40

Positive: Tube like Formation without constrictions ( C. albicans) Negative: Budding cells/Pseudohyphae (C. tropicalis)

Question 41

Special Tests

Answer 41

Hair Perforation Test | Germ Tube Test

Question 42

Chemical Reaction Test

Answer 42

Levodopa Ferric Citrate Test Rapid Urease Test Rapid Nitrate Reduction Test

Question 43

Rapid identification for Cryptococcus neoformans

Answer 43

Levodopa-Ferric Citrate Test

Question 44

Enzyme present in C. neoformans

Answer 44

Phenol oxidase

Question 45

Positive Result for L-DOPA Ferric Citrate Test

Answer 45

Dark Pigmented Compound (Melanin)

Question 46

Positive Result in Rapid Urease Test

Answer 46

Pink-Red Color

Question 47

True or False. Urease test Result C. neoformans - Negative C. albicans - Positive

Answer 47

False. C. neoformans - Positive C. albicans - Negative

Question 48

Principle in Nitrate Reduction Test

Answer 48

Benzalkonium chloride is used to dissociate the cell wall to release nitrate reducatse and addition of N-naphthyl-ethylenediamine and sulfanilic acid

Question 49

Positive Result in Nitrate Reduction Tes

Answer 49

Red Color

Question 50

In nitrate Reduction Test, this is added when color didn't appear after 10 minutes.

Answer 50

Zinc dust

Question 51

General Test for Cryptococcus

Answer 51

Nitrate Reduction Test

Question 52

A simultaneous ID and AST of yeasts for identification and antifungal susceptibility test containing 24 reaction wells

Answer 52

Yeast ID Test

Question 53

Interpretation in Yeast ID Red - Yellow Red - Orange No Color Change

Answer 53

Red - Yellow: Growth of yeast Red - Orange: Slow Growth of yeast No Color Change: No growth

Question 54

Interpretation in Yeast AST Red - Yellow Red - Orange No Color Change

Answer 54

Red - Yellow: Resistant Red - Orange: Intermediate No Color Change: Susceptible

Question 55

Chromogenic well that is a color based distinction for C. albicans and C. tropicalis

Answer 55

No.13 CHR

Question 56

True or False. Interpretation of No. 13 CHR Green Color - C. tropicalis Purple - C. albicans

Answer 56

False. Green Color - C. albicans Purple - C. tropicalis

Question 57

All of the following are examples of appropriate specimens for the recovery of fungi except: A. Tissue biopsy B. CSF C. Aspirate of exudate D. Swab

Answer 57

A: D. Swab Rationale: Generally, swabs are inadequate for the recovery of fungi because they are easily contaminated by surrounding skin flora

Question 58

For which clinical specimens is the KOH direct mount technique for examination of fungal elements used? A. Skin B. CSF C. Blood D. Bone marrow

Answer 58

A. Skin Rationale. 10% KOH is used for contaminated specimens such as skin, nail scrapings, hair, and sputum to clear away background debris that may resemble fungal elements

Question 59

The India ink stain is used as a presumptive test for the presence of which organism? A. Aspergillus niger in blood B. Cryptococcus neoformans in CSF C. Histoplasma capsulatum in CSF D. Candida albicans in blood or body fluids

Answer 59

B. Cryptococcus neoformans in CSF

Question 60

What is the first step to be performed in the identification of an unknown yeast isolate? A. Gram stain smear B. India ink stain C. Catalase test D. Germ tube test

Answer 60

D The true germ tube

Question 61

An isolate produced a constriction that was interpreted as a positive germ tube, but Candida albicans was ruled out when confirmatory tests were performed. Which of the following fungi is the most likely identification? A. Candida tropicalis B. Cryptococcus neoformans C. Candida glabrata D. Rhodotorula rubra

Answer 61

A. Candida tropicalis Rationale. C. tropicalis forms pseudohyphae that resemble true germ tubes by producing a constriction at the point of origin of the yeast cell.