Mycology Flashcards
1
Q
Superficial infection tissues involved
A
outer dead layer, hair, nails
Does not penetrate cell wall, does not initiate host defenses
2
Q
Superficial infection representatives
A
Exophilia, Malassezia
3
Q
Cutaneous infection tissues involved
A
keratinized portion of hair, skin, nails
No invasion of deeper tissues
4
Q
Cutaneous infection representatives
A
Epidermophyton
Microsporium
5
Q
Subcutaneous infection tissues involved
A
Muscle, bone, tissue
6
Q
SQ infection representatives
A
Sporothrix
Cladosporium
Exophilia
7
Q
systemic infections involve
A
any tissues, incl. pulmonary, lymph, circulatory
8
Q
Systemic infections usually begin…
A
in the lungs
9
Q
Systemic infections usually involve ______ fungi
A
dimorphic
10
Q
Systemic infection representatives
A
Histoplasma
Paracoccidioides
Blastomyces
Coccidioides
11
Q
Opportunistic infection tissues involved
A
Any organ or tissue
Fungi nonpathogenic unless host becomes debilitated
12
Q
Media for CNS samples
A
BHI and SABHI, with and without blood
13
Q
CNS probably agent
A
Cryptococcus
14
Q
Media for eye samples
A
SDA, with and without antimicrobials
15
Q
Eye probable agents
A
Fusarium and other opportunistic pathogens
16
Q
Fungemia media
A
BHIA or BHIB in biphasic bottles for specialized containers for lysis-centrifugation or automated methods
17
Q
Fungemia probable agents
A
Aspergillus, Candida, Histoplasma, Torulopsis
18
Q
Hair media
A
SDA with antimicrobials, DTM
19
Q
hair probable agents
A
Dermatophytes, cutaneous fungi
20
Q
Media for Mucocutaneous tissue or mouth and nose (scrapings)
A
SDA and SABHI, with and without antimicrobials, and with and without blood
21
Q
mucocutaneous probable agents
A
Blastomyces
paracoccidioides
22
Q
media for nail scrapings
A
SDA with antimicrobials, DTM
23
Q
Nail probable agents
A
Dermatophytes
candida
24
Q
Respiratory system media (sputa, washings, biopsy tissue)
A
SDA w/ and w/o antimicrobials
SABHI w/ and w/o antimicrobials
25
Respiratory system probable agents
systemic fungi
| yeast
26
skin scraping media
SDA with antimicrobials
| DTM
27
skin scraping probable agents
dermatophytes
| cutaneous fungi
28
SQ lesion media (aspirates, tissue)
SDA w/ and w/o antimicrobials
| SABHI w/ and w/o antimicrobials
29
UTI media
SDA w/ and w/o antimicrobials
| SABHI w/ and w/o antimicrobials
30
SQ lesion probable agents
SQ fungi
31
UTI probable agents
candida
torulopsis
Systemic fungi
32
Vaginal infection media
SDA
33
vaginal infection probable agents
yeast
34
categories for growth rate
1. Rapid Growers
2. Intermediate growers
3. Slow Growers
35
Rapid grower timeframe and examples
<5 days
| saprobes, opportunistic fungi, yeast
36
Intermediate grower time frame and examples
6 to 10 days
| opportunistic fungi, dermatophytes, SQ fungi
37
Slow growers time frame and examples
>11 days
| Systemic fungi, SQ fungi
38
3 problems with immunological methods to screen sera for anti-fungus antibodies
1. Fungus generally not good antigens
2. Fungus usually in one area of the body (ex. nails)
3. Non-specific substances in pt sera (ex. CRP causes false positive test)
39
How to treat mite infestations on media
paradichlorobenzene
40
4 properties of opportunistic fungi
1. Rapid growers- mature in 4 to 5 days
2. Saprobic and airborne- feed off dead, decaying matter enriched with nitrogen
3. Inhaled- not transmitted person to person, but by inhaling spores
4. Opportunistic- not pathogenic unless pt becomes debilitated
41
Aspergillomas are...
balls of hyphae in lungs
| Farmer's lung
42
Aspergillus fumigatus an ______ but also causes _____
opportunist
| infection (aspergillosis)
43
types of aspergillosis
colonization
allergy
disseminated infection
toxicity
44
Zygomycosis characteristics
zygomyces have broad hyphae- penetrate blood vessels, causes blockage, damage, tissue death
45
Hyalohyphomycosis caused by...
hyaline moulds
46
phaeohyphomycosis caused be...
dematiaceous fungi
47
Dematiaceous fungi characteristics
Black/olive/dark
| High quantity of melanin in cell walls
48
Phaeoid
moulds with hyaline hyphae- dematiaceous spores
49
diseases caused by dematiaceous fungi
```
Chromoblastomycosis
Black grain mycetoma
Phaeohyphomycosis (brain abscess and cysts)
IV lines
Superficial skin
```
50
Aspergillus fumigatus characteristic morphology
hyphae branched at 45 degree angle
51
some aspergillus sensitive to _______
cyclohexamide
52
Aspergillus fumigatus grows at ______ C
25 and 37
| Tmax = 50 C
53
charcot-leyden crystals
infection with aspergillus flavus, made with increased eos present
found in sputum and stool
54
Aspergillus flavus does not grow at ___C
45
| Grows best at 37 C
55
Aspergillus niger ____ color, but not _______
black
| not considered dematiaceous
56
A. niger most often reported in _______
otomycosis
57
Bipolaris often implicated in ___ and ____ infections
eye
| nasal
58
fusarium considered a _____ pathogen
plant
59
Fusarium morphology colors
```
immature = white
mature = purple
```
60
significance of Penicillium marneffi
only pathogenic Penicillium species
Dimorphic
takes at least 2 weeks to mature
Grows at 25 to 45 C
61
Trichoderma has been known to cause _____ infections
nosocomial
62
Characteristics of Zygomycetes
Very wide pauci septate
lid lifters
Blocks blood vessels- lumen of vessels may be occluded
Rapid filament growth and rapid destruction
63
5 zygomycete rapid growers
1. Absidia
2. Mucor
3. Rhizomucor
4. Rhizopus
5. Syncephalastrum
64
Absidia rhizoids
present, often indistinct
also has hershey's kiss columella and pear-shaped sporangia
65
Mucor rhizoids
none
Also: straight, long sporangiophores with some branching
66
Rhizomucor rhizoids
randomly throughout
also: columella is half-circle with flattened base
67
Rhizopus rhizoids
at base of sporangiophore
68
Syncephalastrum defining characteristic
spores are produced in multiple tubular merosporangia that radiate from vesicles
More likely to cause onychomycosis and dermatomycosis
69
Most common cause of rhizocerebral and pulmonary zygomycosis
Rhizopus
70
Distinguish rapid growing zygomycetes through
microscopic lactophenol
71
All 5 rapid growing zygomecetes found worldwide in ...
soil and decaying matter
72
All rapid growing zygomecetes found in these patients ....
immunocompromised, debilitated, nutritionally deficient
73
Human zygomycete infections caused by..
inhalation or trauma
74
2 categories of superficial infections
Tineas
| piedras
75
piedra "stone"
hair infection with nodular mass of fungal elements surrounding the hair shaft
No discomfort or hair loss
76
2 types of piedra and agent
White piedra: Trichosporan beigelii
| Black piedra: Piedraia horati
77
Black piedra agent is a ____ whereas white is a ____
mould
| yeast
78
geographic site for black and white piedra
black- tropical
| white- temperate
79
Black piedra tissues involved
scalp hair, eyebrows, eyelashes
80
white piedra tissues involved
mustache, beard, hair of axilla and groin
81
Texture of black piedra nodule is ___ and white is ___
hard
| soft
82
White piedra has ___ colored nodule and is resistant to ____.
```
white or cream
Amphotericin B (use fluconazole)
```
83
2 types of superficial tinea and causative agent
tinea nigra = Exophilia werneckii (mould)
| tinea versicolor = Malassezia furfur (yeast)
84
Tineas geographic site
nigra: tropical
versicolor: temperate
85
Tinea nigra tissues involved and appearance
skin of hands and feet
| dark macular patches that do not fluoresce
86
Tinea versocolor tissues and appearance
skin of chest, arms, back
| skin altered from natural color, lesions may fluoresce
87
Tinea nigra growth characteristics
grows slowly on standard media
| May start out looking like black yeast, but will eventually form olive green color and aerial mycelia
88
Tinea versicolor growth
Yeast requires addition of fatty acids to medium
| Lipolytic
89
malassezia furfur known to cause systemic infections in ____ pts, esp those receiving -___
immunocompromised
| intralipid therapy
90
How to differentiate piedraia hortae from coccidioides immitus.
Piedrae fragments into arthroconidia, but lacks disjuncture cell
91
trichosporan beiglii forms these structures:
hyaline septate hyphae and arthroconidia
Blastoconidia
(yeast-like colonies at 25 C, hyphae and pseudohyphae start to form)
92
Media that provides classic pigment and morphology. Poor recovery for dermatophytes. Good for yeast.
Sabouraud dextrose agar (SDA)
93
Media that enhances the production of reproductive structures and colony color, promotes sporulation
Potato Dextrose agar/Potato flake agar
| PDA/PFA
94
ideal media for slide culture
PDA
95
enrichment media for recovery of yeasts (esp Cryptococcus neoformans)
BHI
96
media that enhances the growth of fastidious dimorphs and used for mould-yeast conversion
BHI
97
Benefit of SABHI media
ingredients of both SDA and BHI
| enriched for recovery of yeasts
98
Inhibitory mold agar
Enriched media that provides better recovery of fastidious fungi.
May/not contain chloramphenicol or gentamicin
99
Mycobiotic agar (Mycocel) contains ______ to inhibit _____ and ______ to inhibit _____
chloramphenicol, bacteria
| cyclohexamide, saprobic fungi
100
disadvantages of mycocel media
true pathogens can sometimes be inhibited by cyclohexamide
chloramphenicol-resistant bacteria may be able to grow
101
dermatophyte test medium contains: (3 things)
antibiotics
cyclohexamide
pH indicator
102
what turns DTM red?
Dermatophytes (white, fluffy)
yeast
Alternaria (brown colonies)
103
Bacteria and saprobes turn DTM ____
yellow
104
CHROMagar candida contains ____ to inhibit bacteria and differentiates yeast by...
chloramphenicol
| Turning different colors for different yeast species (good for mixed cultures)
105
Yeast Extract Phosphate medium (YXP) is selective for ______. Addition of _______ to surface will inhibit yeast
dimorphic fungi
| Concentrated ammonium hydroxide
106
2 things accomplished by Cornmeal agar or Rice Agar with Tween 80 and cornmeal glucose
Produces chlamydoconidium formation in C. albicans
Pigment production in Trichophyton rubrum (red)
107
Purpose of Caffeic acid (bird seed/niger) agar
detection of Cryptococcus neoformans (turns black)
108
cyclohexamide use and precaution
Prevents overgrowth of slowly growing moulds from others that grow faster
May inhibit some pathogens (Aspergillus fumigatus, C. neoformans, Pseudallescheria boydii, Candida krusei, Trichosporan)
109
KOH works by.....
dissolving keratin (strong alkaline solution), making fungal elements more visible
110
KOH combined with _____ is more sensitive, but requires the use of ________ ________
Calcoflour white
| Fluorescent microscope
111
Calcoflour works by....
binding polysaccharides cellulose and chitin, fluoresces when exposed to UV light
112
4 components of Latophenol Cotton Blue and what they do
1) Lactic Acid: cleaning agent and aids in preserving fungal structures
2) Phenol: killing agent
3) Glycerol: Prevents drying
4) Cotton Blue: Gives color to structures
113
LCB stain is used as both a _____ and a ____
```
mounting fluid (tease mount or cellophane tape mount)
stain
```
114
Saline wet mount usually used for...
direct exam for presence of yeasts
115
Gram stain used for....
examining specimens for presence of aerobic actinomycetes
116
acid fast stain is used for... (3 things)
nocardia (partially acid fast staining pink)
ascospores in yeast (stain blue)
Vegetative cells (stain pink)
117
India Ink is used for...
observing CSF for Cryptococcus neoformans/gattii.
118
C. neoformans is detected by (2 methods)
capsular halo when india ink stain used
| direct antigen tests
119
Wrights/Giemsa stain may be used for....
detecting intracellular yeast forms of Histoplasma capsulatum in blood and BM
120
Methenamine silver nitrate is considered most useful ____ method because it provides better ____ than other methods
screening
| contrast
121
GMS stain, fungus stains ____ against _____
black against a pale green background
122
Slide culture method is the best for...
preserving and observing the actual structure of a fungus
123
dermatophytes definition
a fungus that invades the keratinized portion of the hair, skin, and nails
124
dermatophytosis
mycotic infection of hair, skin and nails
125
Dermatomycosis
invasion of cutaneous tissue by other fungi (not dermatophytosis)
126
Athrophilic
People-loving
| Epidermophyton
127
Geophilic
earth-loving
| Microsporium
128
Zoophilic
Animal loving
| Microsporium, Trichophyton
129
5 things to consider if suspecting a dermatophyte
1. Source
2. Presence of Microconidia
3. Macroconidia (# and shape)
4. Teleomorph?
5. Fluroscence
130
"5 things" regarding Epidermophyton
1. Skin, nails
2. no microconidia
3. smooth, thin-walled, sparse macroconidia
4. Teleomorph N/A
5. no fluorescence
131
"5 things: regarding Microsporium
1. hair, skin
2. Few microconidia
3. thick, rough-walled, numerous macroconidia
4. Teleomorph = arthroderma
5. Fluroscence characteristic of some species
132
"5 things" about Trichophyton
1. Hair, skin, nails
2. Many microconidia
3. Smooth, thin-walled, few macroconidia
4. Teleomorph = arthroderma
5. No fluorescence
133
Ring worm
Dermatophyte infection
| Fungus spreads in circular pattern on skin, outer edge alive and sreading
134
Tinea capitis
scalp and hair
135
Tinea barbae
facial hair and beard
136
Tinea corporis
body
137
Tinea cruris
groin
138
tinea pedis
foot
139
Tinea unguium
nails
| associated with onychomycoses, also happens from other types of fungus (aspergillus, candida)
140
Tinea manuum
hands
141
Dermatophyte disease state
Tinea
142
Ectothrix
ability of fungus to grow outside of hair shaft, may resolve on its own
143
Endothrix
ability of fungus to grow and penetrate into the hair shaft
| Can become chronic, would need to treat with systemic meds
144
Hair perforation test looks for....
Trichophyton mentagrophytes
145
4 test methods for dermatophytes
1. Woods lamp (Microsporium- bright yellow/green, others don't fluoresce)
2. Microscopic exam with KOH (10% for hair and skin, 20% for nails)
3. DTM (phenyl red indicator changes media to red with increased pH)
4. PDA (inhibits bacteria)
146
Mycetomas
chronic granulomatous infection typically on the extremities
| SQ
147
Sporotrichosis
"Rose gardener's disease'
Caused by sporothrix schenckii
Chronic infection characterized by nodular lesions of the cutaneous or SQ tissues and adjacent lymphatics that suppurate, ulcerate, and drain.
148
Chromoblastomycosis
Characterized by verrucoid crusted nodules (SQ)
149
Phaeohyphomycosis
Infection caused by dematiaceous fungi (SQ)
150
3 phaeohyphomycoses
Mycetoma
Sporotrichosis
Chromoblastomycosis
151
types of candidiasis
```
Thrush
Vaginosis
balanitis
paronychia
Any organ system (UTI, septicemia, meningitis, endocarditis)
```
152
Yeast vs, yeast-like distinction
True yeasts are a perfect fungus that reproduces sexually and asexually
Yeast-like organisms only reproduce asexually
153
Germ tube
parallel sides
non-septate
no constriction at point of attachment
(99% Germ tube positive yeast are C. albicans)
154
Pseudohyphae
not necessarily parallel
May be septate
Constricted at point of attachment (sausage-shaped)
155
Most frequently encountered fungal opportunist
C. albicans
156
Characteristics of C. albicans
```
germ tubes formed within 3 hours at 35 C
both blastoconidia and pseudohyphae present
Carbohydrate utilization
no capsule
cyclohexamide resistant
```
157
Newest yeast of concern
candida auris
| hard to kill, resistant to many antifungals, septicemia
158
yeast associated with pigeon droppings
cryptococcus neoformans
159
Most common form of cryptococcus infection and specimen
Meningitis (esp in immunocompromised), CSF
160
Advantages and disadvantages of cryptococcal latex agglutination test
Rapid, good for titers
not sensitive, patients with RA or disseminated Trichosporan beigleii infections can cross-react. Would need to boil specimens with Na2EDTA or treat serum with pronase
161
Cryptococcal cells are surrounded by....
refractile mucopolysaccharide capsule
162
2 ways to differentiate cryptococcus from candida
1. Niger seed agar (crypto has melanin)
| 2. urease slant (Crypto is urea Pos, observe for 4 days_
163
I both crypto and candida infections.....
Spinal fluid will have decreased glucose, increased protein, and lymphs will predominate
164
this yeast used to be considered a parasite
pneumocystic carinii
165
Rhodotorula species significance
Increasing infections, found in lungs and UTIs and endocarditis, meningitis, mycotic keratitis, peritonitis
166
Rhodotorula characteristic
Red, coral, orange colored colonies
167
Dimorphs as systemic fungi
A mold that is inhaled at 30 to 35 C and then becomes a yeast in the body at 37 C
168
Conversion of dimorphs in the lab is achieved by:
using fresh BHI agar containing 5 to 10% sheeps blood
169
cottonseed conversion media used for:
| Pros and cons:
Blasto
Pros; enhances recovery of fungus, speeds growth
cons: Blood based media will decrease sporulation
170
Blastomyces dermatitidis endemic to:
North America, surrounding areas of Mississippi, Missouri, and Ohio River Valley
171
2 names for blasto infection
Chicago's Disease
| Gilchrist Disease
172
Blasto found in these environments
moist
| wood, tree bark, rotting vegetation, manure, leaves, river banks
173
Blastomycosis Infection:
A chronic granulomatous and suppurative disease that may affect lungs, skin, mucosal membranes, and other organ systems
174
Chronic cutaneous blasto;
with or w/o lung involvement
verrucous and ulcerated with small abscesses that suppurate and weep
Can spread without treatment
175
Blast specimen
```
sputum or other pulmonary
pus aspirated from lymph node
SQ abscesses
skin scrapings or biopsies from ulcers
21 to 146 day incubation
```
176
Blasto antigens
A and B
A more sensitive and specific, Blastomycin (extract of the yeast form), Can be used for skin testing
177
4 types of blasto immunology tests
1. FA test (fluorescent)
2. ID test (used purified yeast antigen, reference sera)
3. Serological test- EIA (can cross react with Histoplasma, best method)
4. specific A-band exoantigen test
178
Blasto macroscopic morphology
25 C: On modified SABS, mature colonies grow in 6 to 21 days, first colonies are waxy, white/beige and then become fluffy
37 C: on BHI with blood yeasts will appear at 10 to 15 days with wrinkled or folded waxy texture, look dry.
179
Blasta microscopic morphology
25-30 C: fine hyphae, septate and hyaline. Conidia are directly on hyphae or on conidiophores, resemble lollipops
37 C: mother cell attached to daughter by broad base, highly refractile around edges
180
Blasto tissue reactions evoke...
a suppurative, granulomatous response
| neutrophils predominate until it ages
181
Blasto decreased tissue phase response and...
abscesses form a cavity/granuloma that is only detected by X-ray (or DNA probes, exoantigen)
182
Coccidioides immitis endemic to:
hot and dry areas, alkaline soil with high salt content-
| zones of northern mexico and pacific coast of Midwest
183
Names for coccidioides infections;
Valley Fever
| california's disease
184
Most virulent of all human mycoses:
Coccidioides immitis
185
Coccidioides immitis presents increased infection risk to:
Construction workers, farmers, increased rate of lab acquired infections
186
2 common Coccidioides infections:
1. primary pulmonary (asymptomatic, self-limiting)
| 2. meningitis
187
Primary pulmonary Coccidioides more common in ___ than ___.
| Dissemination rate....
Women, men
Dissemination rate 4X higher in men
188
characteristics of primary pulmonary coccidioides
skin eruptions with erythema and nodosum, erythema multiforme may develop.
usually self-limiting, 60% resolve w/o tx
189
Most common cause of Coccidioides infection death
meningitis
190
Coccidioides specimen sources
sputum, pulmonary specimens, aspirated pus, skin scrapings, CSF, blood, urine
191
Coccidioides immunology uses these 2 antigens:
1. Coccidioidin (filtrate prepared from mould cultures)
2. Spherulin (extract from a tissue culture of the yeast form)
Individual antigens have not been characterized
192
Either coccidioidin or spherulin could be used as the...
antigen in coccidioides complement fixation (CF) test
193
Coccodioides tests
DNA probes, exoantigen tests, FA tests
194
Coccidioides temperature considerations
25-35 C: Mould form
37-40 C and increased CO2; tissue phase
(Tmax = 54 C)
195
Coccidioide immitis Macroscopic
arthroconidia will form in 7 to 10 days, giving the colonies a powdery tecture
196
C. immitis microscopic (mould phase)
septate hyaline hyphae
Arthroconidia usually single celled and barrel shaped
alternating disjuncture cells
Raquet hyphae seen in young cultures
197
C. immitis microscopic tissue phase
large, round, tick-walled structures that contain infectious endospores
198
Histoplasma capsulatum endemic to:
central-north America, river valleys: Ohio, Mississippi, Missouri
199
Names for Histoplasma capsulatum disease
Darling's disease
Cave fever
Spelunker's disease
200
H. capsulatum associated with...
soil with increased nitrogen from deposits of chickens, bats, birds (starlings)
201
H. capsulatum transmission
airborne, highly infectious
202
histoplasmosis
Chronic granulomatous disease that involves the lungs and RE system
203
Main characteristic of Histoplasma infection
```
coin lesions (seen in X-rays;
Fibrosis around the cavities in the lungs causing flat, round areas)
```
204
Fibrosing medastinitis
You had the disease, it's treated and cured, but still have disease progression due to scar tissue
205
Histoplasma capsulatum specimens
sputum and other pulmonary, lymph nodes, SQ abscesses, skin scrapings and other tissues
206
H. capsulatum detection methods
```
complement fixation (sensitive but not specific)
Titers (appear within 2 to 3 weeks of exposure)
```
207
histoplasma macroscopic
25 C: SABS agar, matures in 15 to 25 days
37 C: BHI with blood, colonies in 10-15 days
(slow growing)
208
histoplasma mould microscopic
some isolates do not sporulate
| macroconidia- unicellular, spherical or pyriform shapes, become tubular as they age (Sunflowers0
209
histoplasma tissue phase microscopic
Small, round oval yeast
| Found primarily in macrophages by GMS, PAS, H&E stains
210
histoplasma infections invoke a ...
lymphocyte response
211
Paracoccidioides brasiliensis is AKA
South American blasto
212
p. brasiliensis infection transmission:
highly infectious, airborne transmission via contaminated plants
213
Most common form of p. brasiliensis infection
Pulmonary Paracoccidioides, asymptomatic and self-limiting
214
Paracoccidioides secondary infections...
usually occur on the face, mucous membranes, nose, mouth, throat
215
P. brasiliensis specimens
sputum, respiratory, skin scrapings
216
Methods of detecting P. brasiliensis
complement testing with Immune diffusion (98% specificity if you have symptoms)
Direct FA testing
217
P. brasiliensis at 25 and 37 C
25 on SABS: 2-3 week incubation, very tiny and hard to see, mould form has oval conidia with truncate bases
37: yeast-like colonies in 10-15 days
Tissue phase: Mariner's wheel
218
single conidia at ends of hyphae or conidiophores
blasto mould form
219
broad based budding yeast
blasto tissue phase
220
Alternating arthroconidia with disjuncture cells
coccidioides at room temp
221
spherical endospores
Coccidioides tissue phase
222
macroconidia with fin0like tuberculate edges
histoplasma at RT
223
Intracellular, small round budding yeast
histoplasma tissue phase
224
Hyphae with terminal and intercalary conidiophores
Paracoccidioides
225
Mariner's wheel
Paracoccidioides tissue phase
