Lab Diagnosis Of Fungi Flashcards
1
Q
What class of BSC should be used?
A
Class II biological safety cabinet
2
Q
True or false
Petri dishes are not recommended since it is hazardous to use
A
True
3
Q
Used to eliminate the hazards of open gas flames and contain particles emitted when loops or needles are incinerated
A
Enclosed electric incinerator
4
Q
It has a larger surface area for colony isolation and are easier to manipulate when making preparations for microscopic examination
A
Petri dish
5
Q
Cite 3 advantages of using screw top tubes
A
Release of airborne conidia is less likely
Show less media dehydration
More easily handled and stored
6
Q
Cite 5 Most common spx
A
Respiratory secretions Hair Skin Nails Blood
Bone marrow
7
Q
Primary criterion for accurate diagnosis of mycotic infections
A
Collection of appropriate spx
8
Q
True or false
Spx submitted for systemic culture are generally contaminated with bacteria, rapidly growing fungi or both
A
False
Dermatophyte culture (hair, skin, nails)
9
Q
Primary isolation medium should contain
A
Antimicrobial agent
10
Q
Wood’s lamp emits UV at what wavelength
A
> 365 nm
11
Q
Useful in identifying infected hair
A
Wood’s lamp
12
Q
Hair can either be pulled or cut. Using what equipments?
A
Sterile forceps and scissors
13
Q
True or false
Cutting the hair close to the scalp is a less useful method.
A
True
14
Q
Fungal medium with hair is incubated at what temp?
A
Room temp. 22 - 30 degree celsius
15
Q
Skin samples are scraped from?
A
Outer edge of surface lesions
16
Q
Skin must be cleaned with
A
70% isopropyl alcohol
17
Q
It breaks down the tissue to view fungal hyphae.
A
Potassium hydroxide
18
Q
Nail spx may be submitted as
A
Scrapings or cuttings or complete nail
19
Q
True or false
Deeper scrapings are necessary to prepare KOH prep
A
True
20
Q
What medium is used when suspecting malasezzia furfur
A
SDA w/ olive oil
21
Q
Concentration of KOH in hair culture
A
10 - 20% KOH
22
Q
Percentage of KOH for skin and nails
A
10% KOH
23
Q
It is the most sensitive method for the recovery of some fungi from blood and bone marrow
A
Lysis centrifugation system
24
Q
A system which contains both agar and broth culture media
A
Biphasic system
25
This spx should be directly plated at culture medium for blood and bone marrow spx
Heparinized bone marrow
26
True or false
| Blood culture bottles are not recommended for blood and bone marrow.
True
27
Using dissecting microscope, one can examine abscess fluid and exudate for the presence of what?
Sulfur granules
28
Grinding of tissue may destroy fragile fungal elements particularly if _______ is present
Zygomycete
29
Abscess fluid , wound exudates and tissue samples are collected through
Needle aspiration or biopsy
30
Respiratory spx
Sputum, endotracheal lavage / transtracheal lavage, bronchoalveolar lavage
31
______ is routinely performed for CSF and other sterile body fluids
Gram stain
32
Csf and other sterile body fluids are concentrated by ______ before incoulation
Centrifugation
33
A drop of CSF ( or sterile fluid) concentrate is used for what test ? Aids in identifying Cryptococcus
Latex agglutination or india ink prep
34
True or false
| CSF spx should be inoculated in a medium with antimicrobial agent to avoid contaminants.
False
It is no longer needed since csf is normally sterile
35
Culture medium for blood and bone marrow spx
BHI, tryptic soy broth,
36
Optimum spx for respiratory
Deep cough and early morning (first morning spx)
37
It is used to induce sputum
Nebulizer
38
All sputum spx should be collected into a
Sterile, screw top container
39
Example of viscous materials
Thick tracheal aspirate
40
Viscous materials can be inoculated onto media using
Dacron swab
41
Viscous materials are preferably digested with what mucolytic agent
N-acetyl-L-cysteine
42
Abscess and lesions should be...
Homogenized or gently minced
43
Selective chromogenic agar that provides a rapid preliminary identification of Candida spp
CHROMagar Candida
| Candida ID
44
Nasal spx obtainedsurgically can be plated directly onto media containing antimicrobial agents except for...
Cycloheximide
45
Theoat, vaginal and cervical spx requires how many swab
Two
46
Urogenital and fecal spx occasionally grow what fungi
Yeast
47
Type of urine spx submited for fungal culture
First morning urine spx
48
This often qifts the first evidence of infections with bacteria and yeast
Gram stain
49
Types of direct examination used in identification of fungal infxn include:
KOH, india ink and calcofluor white
50
A yeast important cause of hospital acquired infections and can also be a part of normal biota
Candida albicans
51
Steps in KOH prep
```
Drop of KOH on slide
Nail, skin scales, or think slices of tissue are added to drop
Cover slip is added
Slide is gently heated
Cooled for approx. 15 mins
```
52
KOH breaks down what to see fungi present more easily
Keratin and skin layers
53
Modified KOH test has incorporated what substances
Dimethyl sulfoxide (DMSO) and stain
54
It binds to the polysaccharides present in chitin
Calcofluor white
55
Facilitates more rapid breakdown of cellular debris without requiring heat while the stain is taken up by fungal elements
DMSO
56
Calcofluor white fluoresces what color
Blue white or apple green
57
A drop of calcofluor white can be added to what prep
KOH preparation
58
This stain shows a budding yeast surrounded by a large clear area against a black background
India ink or nigrosin
59
This test is more specific and can be used in place of india ink
Cryptococcal antigen latex agglutination for system (CALAS)
60
Stains specifically the melanin content of phaeoid fungi
Fontana Masson
61
LPCB is used in what medium
Aman medium
62
Stains the fungal morphology
LPCB
63
Binds to the polysaccharide cell wall
PAS
64
Postive color of PAS
Purplish red or pink
65
Giemsa stain is used to detect specifically what fungi in blood and bone marrow spx
H. capsulatum
66
Cite 3 types of standard media
Sabouraud dextrose agar
Potato dextrose agar
BHI with blood and antimicrobial
67
Gentamicin and chloramphenicol inhibit what
Bacterial growth
68
Cycloheximide inhibit what
Bacteria and environmental fungi
69
Mediums for primary isolation method
BHI, SDA, BHI-CC, Mycosei or mycobiotic Agar, Dermatophyte test medium (Pfizer)
70
pH indicator of DTM
Phenol red
71
This medium is used to isolate c. Neoformans, and contains phenol oxidase (black brown colonies)
Birdseed (niger seed) agar
72
Used to isolate B. Dermatitidis and induces its conversion from mold to yeast
Cotton seed agar
73
Components of hair baiting test
Use sterile + water w/ 10% yeaat extract
74
Trichophyton agar are 7 agars with what base
Casein or Ammonium nitrate
75
Diferential test medium used for species identification of aspergilli
Czapek’s
76
Induces pigment production of T. Rubrum and stimulates conidia production
Potato dextrose agar
77
Medium used to differentiate microsporum spp
Rice medium
78
Detects urease activity of cryptococcus neoformans and differenctiates T. Rubrum from T. Mentagrophytes
Christensen’s urea agar
79
It is a candida differential agar
Chromogenic agar
80
It is probably the most important and easiest test to perform for the identification of yeasts
Germ tube test
81
Spx used for germ tube
Plasma or serum
82
Germ tube identifies what species of candida
C. Albicans and c. Dubliensis
83
Serum is incubated at what temp and how many hrs to exhibit germ tubes
36-37 degree celsius; 3 hrs
84
C. Dubliensis is differentiated from albicans by what
Inability to grow at 42 degree celsius
85
Medium used to assess utilisation of carbon and nitrogen
Yeast assimilation media
86
It is used to identify the ability of yeast to ferment carbohydrates
Yeast fermentation broth
87
What fermentation broth test is most commonly used
API 20C
88
Media that Stimulates conidia and chlamydospore production of candida
Cornmeal agar wt tween 80
89
It is present in most cell wall of yeast and molds
(1-3)-beta-D-Glucan
90
Positve rxn of (1-3)-b-D-glucan detection assay?
Yellow
91
What does (1-3)-b-D-glucan activates?
Coagulation cascade in limulus amebocyte lysate
92
What the growth requirements
Nutrient and mositure, temperature and time
93
Nutrional requirements
Nitrogen, carbon, vitamins and minerals
94
Time requirement for growth
2-4wks for mold
| 2-3 days for yeast
95
Methods for examination for growth
Cellophane tape mount
Tease mount
Slide culture
96
This antifungal agent is used to threat life threatening fungal infxn and belongs to what family
Amphotericin B
| Polyene family
97
Commonly used to threat thrush and vaginitis
Fluconazole
98
The largest family commonly used to treat infxn
Azole
99
This antifungal agent targets cell wall synthesis
Caspofungin
100
Broth microdution for yeast
M27-A3
101
Disk diffusion for yeast
M44-A
102
Broth microdilution for mold
M38-A2
103
Fast growing fungi
Mucor and rhizopus spp
104
Growth time for phialophora or Fonsecaea
2 wks or longer
105
Most common procedure for microscopic exam
Direct mount of fungal isolate
106
Tape and tease mount disturb what
Conidia
107
This method provides a more intact spx and conidial arrangement are better observed
Slide culture
108
This stain is used to fix and stain tease or tape mount from cultures
LPCB
109
Cellophane tape prep should be read within ? (Time)
30 mins
110
True lr false
| Conidial arrangement is retained using cellophane tape prep
True
111
True or false
| Slide culture are useful for demonstrating the natural morphology of fungal structures and for encouraging conidiation
True
112
The single most useful nutritional test fordermatophytes
Thiamine requirement
113
These germ tubes lack constriction at their bases
True germ tube
114
Constricted germ tubes sre called
Pseudo-germ tubes
115
Recognition of 4 diff types of morpholog, important clue to yeast identification (cornmeal)
Arthroconidia
Chlamydoconidia
Pseudohyphae
Blastoconidia
116
Produced when blastoconidia germinate to form filamentous mat
Pseudohyphae
117
These structure helps to determine true hyphae or pseudohyphae
Cross walls
118
Begins as true hyphae but breaks apart
Arthroconidia
119
Separate clinically significant yeasts
Potassium nitrate assimilation
120
Positive result of potassium nitrate
Blue - cryptococcus albidus
121
Negative result of KNO3
Yellow - candida albicans
122
Amphotericin B resistance
Pseudallescheria boydii and paekilomyces lilacinus
123
Fluconazole resistance
C. Glabrata
124
Susceptible dose dependent And prescribed for mold infection
Itraconazole, posaconzaole and voriconazole
125
Itraconazole treats what
Aspergilli and phaeoid
126
Improved activity against aspergilli
Voriconazole
127
Newest azole &best activity against fungal spp
Posaconazole
128
Fungi infection in blood
Histoplasmosis
129
Fungi infection in the bone
Blastomycosis
