MYCOVIRO - CH 59 Book Pt 2 Flashcards Preview

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Flashcards in MYCOVIRO - CH 59 Book Pt 2 Deck (64):
1

Vaginal Samples
-transported to lab within ? hrs using culture transport swabs

24

2

Vaginal Samples
-transported to lab within 24 hrs using __

culture transport swabs

3

vaginal samples: both __ and __ agars be plated

selective and inhibitory

4

vaginal samples must be screened for __, incubated at 30C for 7 days

yeasts

5

vaginal samples must be incubated at (temp and how many days)

30C for 7 days

6

what urine sx is unacceptable for culture

24-hr urine

7

urine sample media must contain what ?

antibacterial agents

8

All tissues must be processed before culturing by: (2)

• Mincing
• Or placement in high speed lab blender

9

express the cytoplasmic contents of cells using pressure from the action of rapidly moving metal paddles

stomacher lab blender

10

what specimen may be placed directly onto the surface of appropriate culture media

BM

11

For optimal recovery, a battery of media should be used:
(2)

• Media with and without cycloheximide
• Media with and without antibacterial agent (not necessary if specimen is from a sterile site)

12

Agar plates – preferred because (3)

• Provide better aeration
• Larger surface area for better isolation of colonies
• Greater ease of handling

13

agar tends to dehydrate during extended incubation period
--minimized using: ??

culture dishes containing at least 40 mL agar and placing them in a humidified incubator

14

ADV OF SCREW-CAPPED CULTURE TUBES

• Easily stored
• Require less space for incubation
• Easily handled
• Lower dehydration rate
• Less hazardous

15

DISADV OF SCREW-CAPPED CULTURE TUBES

• Poor colony isolation
• Reduced SA
• Tendency to promote anaerobiosis

16

if using screwcapped culture tubes, after inoculation, must be placed in a horizontal position for at least ??? hours to allow the specimen to absorb the agar surface and avoid settling at the bottom of tube

1-2

17

?? tubes unsatisfactory for fungal cultures

cotton-plugged tubes

18

cultures should be examined at least how many times weekly during incubation

3x

19

– added to any media that contain or lack antibiotics
-if it is included, a medium w/o it must also be used
-partially or completely inhibits…

Cycloheximide

20

– recommended method for direct microscopic examination

KOH preparation

21

- better than KOH preparation
-slides are observed using 1) fluorescent microscopy (optimal because fungal cells fluoresce) or 2) bright field microscopy

Calcoflour white stain

22


Serology testing - may be useful for (4, CHAB)

• Cryptococcus
• Blastomyces
• Histoplasma
• Aspergillus

23

– useful but not for immunocompromised patients (incapable of producing a measurable humoral response)


Antibody testing

24

– sensitive method, difficult to perform and interpret
-requires a delay in testing that extends from exposure to onset of symptoms
-detection of antibody can take 2 to 3 months
-cross reactions with other fungal antibodies may be a problem

Complement fixation (CF)

25

– simple, cost-effective procedure
-100% specific, relatively insensitive, not used as a screening tool
-requires 2-3 weeks to be positive

Immunodiffusion testing

26

– frequently negative in immunocompromised patients especially early in the infection


Enzyme immunoassays

27

- not accepted as a routine diagnostic tool in mycology

Molecular Detection

28

– biophysical method that reduces time required to specifically identify fungal organisms

MALDI-TOF

29

MALDI-TOF MEANING

Matrix-Assisted Laser Desorption Ionization

30

For Yeast ID
Many automated and semiautomated commercial systems have been designed with WHAT tests because C and N source differences are key to yeast differentiation)

assimilation and fermentation

31

o – differentiates yeast presumptively

Chromogenic agar

32

ID factor Most helpful when a mold culture is examined

Growth rate

33

– form mature colonies in 11 to 21 days

slow growers

34

– 6 to 10 days

Intermediate-growers

35

– 5 days or less

Rapid-growers

36

– various elevations on agar plate

• Colony topography

37

Colony topography
furrowed or convoluted

verrucose

38

Colony topography
slightly raised in the center

umbonate

39

Colony topography
– furrows radiate out from the center

rugose

40

colony texture
loose, high aerial mycelium

cottony

41

colony texture
low aerial mycelium resembling a velvet cloth

velvety

42

colony texture
smooth surface with no aerial mycelium

glabrous

43

colony texture
– dense, powdery, like sugar granules

granular

44

colony texture
high aerial mycelium like slightly matted down

wooly

45

o Fungi Preparation for Microscopic Examination (4)

• Cellophane (Scotch) tape preparation – traditional; easy and quick
• Wet mount
• Tease mount
• Microslide culture method

46

Fungi Preparation for Microscopic Examination – traditional; easy and quick

Cellophane (Scotch) tape preparation

47

Fungi Preparation for Microscopic Examination
used when greater detail of morphology is required

• Microslide culture method

48

hyphae type
curved freely branching, antler-like

antler hyphae

49

hyphae type
– enlarged, club-shaped

Racquet hyphae

50

hyphae type
produced by some dermatophytes; coiled corkscrewlike

spiral hyphae

51

type of hyphae common in dermatophytes

spiral

52

asci contains how many ascospores

4-8

53

Types of Conidia (both types not specific)– small, unicellular, round, elliptical or pyriform
-may be born directly on the side of a hyphal strand or at the end of a conidiophore

Microconidia

54

Types of Conidia (both types not specific)
large, multiseptate, club or spindle shaped
-borne on a short to long conidiophore
-may be smooth or rough walled

Macroconidia

55

– pinching off
-manner by which conidia are freed from their point of attachment

Abstriction

56

– formed directly from the hyphae by fragmentation through the points of septation
-mature: square, rectangular, barrel-shaped, thick-walled cells


Arthroconidia

57

– round, thick-walled spores formed directly from differentiation of hyphae in which there is a concentration of protoplasm and nutrient material
-resistant resting spores

Chlamydoconidia (chlamydospores)

58

-may be intercalary (w/in hyphae) or terminal (end of hyphae)

Chlamydoconidia (chlamydospores)

59

Chlamydoconidia (chlamydospores) within hyphae

intercalary

60

Chlamydoconidia (chlamydospores) at end of hyphae

terminal

61

o If a laminar flow BSC is used, a BSC with??? not necessary.

gloves

62

• Yeast cultures may be handled on a __

bench top

63

??? is suitable for decontaminating a loop used to transfer yeast cultures

Eletric incinerator or gas flame

64

• Cultures of organisms suspected of being pathogens should be??? to prevent laboratory contamination and should be autoclaved as soon as definitive ID is made.

sealed with tape

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