2. Basic Clinical Mycology (III) Flashcards Preview

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Flashcards in 2. Basic Clinical Mycology (III) Deck (44):
1

Microscopic morphology of molds used in its ID

Septate/aseptate hyphae
Conidiophore structure
Microconidia/macroconidia

2

Rapid information of immunoidentity for mold ID

Exoantigen test

3

Exoantigen test is read at

24 hours

4

Fungi ID through exoantigen test

Blastomyces
Coccidioides
Histoplasma

5

How to do exoantigen test?

- extract soluble antigen from unknown isolate
- concentrate
- react with antiserum specific to known fungi
- positive control necessary for definitive ID

6

Principle used in DNA probe kits

Nucleic acid hybridization

7

DNA probe can only be performed on

Cultured organisms

NOT on specimens

8

Advanced technique for mold ID that can only be performed on cultured organisms

DNA probe

9

DNA probe was developed for

Balastomyces
Coccidioides
Histoplasma

10

Macroscopic morphology of yeasts used in its ID

Color
Texture

11

Color of yeast colonies

White
Tan
Pink
Salmon

Can have dematiaceous yeasts

12

Texture of yeast colonies

Mucoid
Butterlke
Velvety
Wrinkled

13

Method for microscopic examination of yeasts

Wet preparation

14

Microscopic morphology of yeasts used in its ID

Hyphae
Pseudohyphae
Blastoconidia

15

Media for yeasts that encourage development of chlamydospores

Cornmeal Tween 80 agar

16

Develops in Cornmeal Tween 80 agar

Chlamydospores

17

Clear media that can be observed under a light microscope

Cornmeal Tween 80 agar

18

Cornmeal agar morphology for yeasts is used in conjunction with

Carbohydrate usage

19

4 main morphology types in Cornmeal Tween 80 agar

Hyphae
Pseudohyphae
Arthroconidia
Chlamydoconidia/blastoconidia

20

Fungi with pseudohyphae and blastoconidia only on Cornmeal Tween 80 agar

C. krusei
C. parapsilosis
C. kefyr
C. tropicalis

21

Fungi with blastoconidia only on Cornmeal Tween 80 agar

C. glabrata
C. neoformans

22

Fungi with arthroconidia only on Cornmeal Tween 80 agar

Trichosporon beigelii

23

Physiologic tests for yeast ID

Germ tube test
Fermentation/assimilation
Urea hydrolysis

24

Most basic and easiest physiologic test for yeasts to perform

Germ tube test

25

Filamentous outgrowth from blastoconidia

Germ tube

26

The germ tube test for yeast ID requires

Serum or plasma

Commercial boths will last longer

27

Biggest problems in performing germ tube test for yeast ID

Overincubation
Overinoculation

28

Germ tube test reading for yeast ID is not valid if read after

2 hours

29

Produces "true" germ tubes

C. albicans

30

Characteristics of a true germ tube

No constriction at the base where the tube attaches to the mother cell

31

Produces germ tubes with a constricted base

C. tropicalis

32

Other yeasts that produce germ tubes

C. stellatoidea
C. dubliniensis

33

How do you differentiate C. albicans from C. stellatoidea since both produce germ tubes?

Use sucrose assimilation

34

Differentiating characteristic of C. dubliniensis from other yeasts

No growth at 45°C

35

Yeast that does not grow at 45°C

C. dubliniensis

36

Physiologic test for yeast ID that determines carbohydrate use in absence of oxygen

Fermentation

37

Commercial products for fermentation/assimilation physiologic test for yeast ID

API 20C: strip test
Vitek: automated

38

Fungi differentiated using urea hydrolysis physiologic test for yeast ID

Cryptococcus
Rhodotorula

39

Positive result in urea hydrolysis physiologic test for yeast ID

Pink

40

Negative result in urea hydrolysis physiologic test for yeast ID

Little to no change

41

Temperature study of Cryptococcus spp.

35°C: weak growth
42°C: no growth

42

Temperature study of Candia spp.

Several spp. can grow well exceeding 45°C

43

Order of events for yeast ID

- wet preparation
- germ tube test
- corn meal morphology
- physiologic/biochemical tests
- temperature

44

Advanced techniques for mold identification

Exoantigen test
DNA probe