LAB DIAGNOSIS OF FUNGI Flashcards

1
Q

SAFETY ISSUES..

BSC level used in lab is..

A

Class II Biological safety cabinet

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

SAFETY ISSUES..

  • To eliminate that hazards of open gas flames
  • To contain particles emitted when loops or needle are incinerated.
A

Electric incinerator

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

SAFETY ISSUES..

In petri dish, ________ area for colony isolation

A

large surface area

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q
  • Easier to manipulate when making preparations
A

petri dish

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q
  • Tend to show less media dehydration (esp. swab, abscess, etc.)
A

screw-top tubes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

SPECIMEN COLLECTION, HANDLING, AND TRANSPORT..

All specimens must be transported and processed _____

A

ASAP.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Most common specimens:

A
  • Respiratory secretions, Hair, Skin, Nails primary isolation medium, tissue, blood, bone marrow , & CSF
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q
  • Wood lamp – ultraviolet light - >360nm
  • (+) fluorescence – M. audouinii
  • _____ is inoculated into fungal medium and
    incubated at 22°C - 30°C
A

Hair

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q
  • Scraped from the outer edge of the surface lesion
  • Must be cleaned with 70% isopropyl alcohol
  • KOH wet mount
A

Skin

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

breaks down tissue making it easier to view fungal hyphae.

A

KOH

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

a collected sample of skin cells that are evaluated under the microscope.

A

Skin scraping

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Scrapings or cuttings and complete ____

A

nail

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q
  • Lysis centrifugation system – isolator tube
  • Centrifugation
  • Biphasic system
A

blood and bone marrow

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

most sensitive method for recovery of some fungi. Lysis of WBC and RBC releases microorganisms.

A

Lysis centrifugation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q
  • Concentrated by centrifugation before inoculation
  • Cryptococcus – India ink or Latex Agglutination
A

CSF

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q
  • Examine the presence of granules (abscess fluid & exudate from wound)
A

Abscess Fluid, Wound Exudates, and Tissue

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

necessary for KOH and Calcofluor White prep

A

Grinding of Tissue

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Lower respiratory secretions:

A

Sputum, tracheal aspirates & pleural lavage

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

In respiratory specimens..

If material is not too viscous

A

inoculate to media using sterile pipette

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

In respiratory specimens..

If material is viscous

A

Dacron swab maybe used to inoculate on media → digestant

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

In respiratory specimens..

Nasal Sinus specimens

A

plate to media containing antibiotics except cycloheximide.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

In Urogenital and Fecal Specimen, use..

A

1st morning urine, feces, vaginal secretion

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

In Urogenital and Fecal Specimen

A

Centrifuge → sediment → inoculate to media

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

KOH Preparation

A

10%-20% solution – detect fungal elements within skin, hair, nails, and tissue.

Specimen + KOH + coverslip (heat fixed)

Breaks down the keratin and skin layers to see fungi present

Modification: KOH + Dimethyl sulfoxide (DMSO)
DMSO – facilitate more rapid breakdown of cellular debris without heat while the stain is taken up by fungal elements.

25
Q

Breaks down the keratin and skin layers to see fungi present

A

KOH

26
Q

KOH modification

A

KOH + DMSO (dimethyl sulfoxide)

27
Q

Facilitate more rapid breakdown of cellular debris without heat while the stain is taken up by fungal elements.

A

DMSO

28
Q

KOH with Calcofluor White

A

Calcofluor White – fluorescent dye; binds to polysaccharides present in the chain of the fungus or to cellulose

Positive (+): Fluoresce → Apple-green or Blue-white

29
Q

fluorescent dye; binds to polysaccharides present in the chain of the fungus or to cellulose

A

Calcofluor White

30
Q

calcofluor white positive

A

Fluoresce → Apple-green or Blue-white

31
Q

India Ink (a.k.a nigrosin)

A

Examine CSF for the presence of encapsulated yeast C. neoformans

Ink + sediment → HPO

Serological test: Latex Agglutination test

32
Q

Examine CSF for the presence of encapsulated yeast C. neoformans

A

India Ink (a.k.a nigrosin)

33
Q

India Ink (a.k.a nigrosin) serological test

A

Latex Agglutination Test

34
Q

Tissue Stains (Provides a rapid report to physician)

A

Periodic Acid Schiff (PAS) – attaches to polysaccharides in the fungal wall. Stains pink

Gomori-Methenamine – Silver nitrate

Hematoxylin and Eosin

Fontana-Masson Stain – identifies the presence of
phaeoid fungi; stains the melanin in cell wall.

Giemsa Stain – detect H.capsulatum in blood or BM

35
Q

attaches to polysaccharides in the fungal wall. Stains pink

A

Periodic Acid Schiff (PAS)

36
Q

Silver nitrate

A

Gomori-Methenamine –

37
Q

identifies the presence of
phaeoid fungi; stains the melanin in cell wall.

A

Fontana-Masson Stain

38
Q

detect H.capsulatum in blood or BM

A

Giemsa Stain –

39
Q

WHAT STAIN..

Color of Fungal Element: Magenta
Background Color: Pink or Green

A

Periodic acid-Schiff

40
Q

WHAT STAIN..

Color of Fungal Element: Black
Background Color: Green

A

Gomori-Methenamine Silver

41
Q

WHAT STAIN..

Color of Fungal Element: Purple-to-blue yeast with clear halo
Background Color: Pink to purple

A

Giemsa

42
Q

WHAT STAIN..

Color of Fungal Element: Yeast with clear halo
Background Color: Black

A

India Ink

43
Q

WHAT STAIN..

Color of Fungal Element: Refractile
Background Color: Clear

A

KOH

44
Q

WHAT STAIN..

Color of Fungal Element: Fluorescent
Background Color: Dark

A

KOH-Calcoflour White

45
Q

WHAT STAIN..

Color of Fungal Element: Brown
Background Color: Pink to Purple

A

Masson-Fontana

46
Q

CULTURE MEDIA..

used for demonstration of pigment production by Trichophyton rubrum; preparation of microslide cultures and sporulation of dermatophytes.

A

Potato Dextrose Agar

47
Q

CULTURE MEDIA..

enhances recovery of B.dermatitidis and H.capsulatum

A

Yeast Extract Phosphate Agar

48
Q

CULTURE MEDIA..

identification of Cryptococcus, Trisporon and Rhodotorulla.

A

Christensen Urea Agar

49
Q

CULTURE MEDIA..

for chlamydospore production of C. albicans.

A

Cornmeal agar with Tween 80 and Trypan Blue

50
Q

CULTURE MEDIA..

conversion of dimorphic fungus B. dermatitidis from mold to yeast.

A

Cottonseed Conversion Agar

51
Q

CULTURE MEDIA..

differential for aspergillus

A

Czapek’s agar

52
Q

CULTURE MEDIA..

for identification of C. neoformans

A

Niger Seed Agar

53
Q

INCUBATION..

A

Room temp. or 30°C

Dimorphic – RT and 37°C

Generally maintained for 4-6 weeks

Examined 2x weekly for growth

Mucor and Rhizopus spp. – grow rapidly

Fonsecaea or Phlalophora spp. – slow growing

Rapid – 1-3 days; Intermediate – 5-9 days; Slow – 2 weeks ++

54
Q

Gross morphologic traits

A

color, texture, growth rate & pigmentation

55
Q

Most common MICROSCOPIC procedure:

A
  1. Tease mount
  2. Cellophane Tape mount
56
Q

Microscopic characteristics that should be observed are the ff:

A

a. Septate vs. sparsely septate hyphae
b. Hyaline or Phaeoid hyphae
c. Fruiting structures
d. Types, size, shape, arrangement of conidia

57
Q

Two teasing needles are used to remove a portion of mycelium from the middle third of the colony.

Mycelia + drop of lactophenol cotton blue (LPCB) on a slide and gently teased apart using needles.

Examined microscopically.

LPCB – used to fix and stain tease or tape mounts from cultures.

A

Tease Mount

58
Q

Involve gently touching a piece of clear tape (sticky side) to the surface of the colony.

Tape is placed onto a drop of LPCB in a slide and examined.

Should be read within 30 minutes then discarded.

A

Cellophane Tape Preparation