Exam 5 Mycology Flashcards
1
Q
Fungi cell wall contains:
A
Chitin, mannoproteins, glucans
2
Q
Fungi cell membrane contains ____
A
Ergosterol
3
Q
Which 5 major classes of fungi cause human disease?
A
- Mucormycetes
- Basidiomycetes
- Pneumocystidiomycetes
- Saccharomycetes
- Euascomycetes
4
Q
Fungi can have what kinds of morphology?
A
- Yeasts
- Hyphae
- Dimorphic
5
Q
____ are unicellular and reproduce by budding
A
Yeasts
6
Q
What is the structure of hyphae?
A
- Multicellular
- Septate or non-septate
7
Q
____ are masses of hyphae (____)
A
Mycelia; molds
8
Q
What does dimorphic mean?
A
Different forms at different temperatures (yeast at 37C, mycelia at 25C)
9
Q
Most species of fungi form ____
A
Spores
10
Q
Fungi can undergo asexual reproduction to form what kinds of asexual spores?
A
- Sporangiospores
- Conidia
11
Q
Sporangiospores are formed within ____
A
Sporangia (sac)
12
Q
Conidia are formed at ____ or by ____
A
Tips of hyphae; hyphal fragmentation
13
Q
Arthrospores form via ____ and are a type of ____
A
Hyphal fragmentation; conidia
14
Q
Sexual reproduction in fungi is by means of ____
A
Sexual spores (zygospores)
15
Q
Zygospores are formed by:
A
Nuclear fusion of 2 haploid cells
16
Q
Fungal nutrition: yeasts use ____ and molds use ____
A
Facultative anaerobes; mainly aerobes
17
Q
Fungal colonies can be cultured on what mediums?
A
- Sabouraud agar
- Pagano-Levin agar
18
Q
Sabouraud agar usually contains ____ and incubate aerobically in ____
A
Antibacterial agents; high humidity
19
Q
What is Pagano-Levin agar used for?
A
To distinguish different Candida species
20
Q
Microscopic examination of fungi can be done through what techniques?
A
- Potassium hydroxide (KOH)
- India Ink
- Gomori methamine silver (GMS) stain
- Immunofluorescence of chitin
21
Q
____ preparation is cheap and fast, and can be used for oral, vaginal, skin scrapings or squamous epithelial cells scrapings
A
KOH preparation
22
Q
True or false: antigen or antibody detection is another fungal identification method
A
True
23
Q
What do polyenes do?
A
Anti-fungal therapy that binds to ergosterol and disrupts cell membrane
24
Q
What do azoles inhibit?
A
Ergosterol synthesis
25
____ inhibit cell wall (glucan) synthesis
Echinocandins (Micafungin)
26
Naftifine inhibits:
Ergosterol synthesis
27
Griseofulvin inhibits:
Mitosis
28
Malassezia infects what layer?
- Superficial (epidermis)
- outermost layers of skin
29
Describe Malassezia classification
- Lipophilic
- Budding yeast-like cells
30
What disease does Malassezia cause?
Tinea versicolor
31
What are some very common diseases caused by Malassezia?
- Folliculitis
- Venous catheter infection
32
Malassezia Tinea versicolor lesions can appear ____ or ____
Hypo or hyperpigmented
33
Dermatophytes infect what part of the skin?
Dermis (cutaneous)
34
List the names of the 3 dermatophytes
- Trichophyton
- Microsporum
- Epidermophyton
35
____ cause Tinea
Dermatophytes
36
What is Tinea?
Ringworm-shaped mycoses
37
Tinea caused by dermatophytes are classified by what?
Structure affected
38
Trichophyton commonly affects what parts of the body?
Skin, hair, nails
39
Trichophyton rubrum is the most common cause of ____
Athlete's foot
40
Trichophyton tonsurans is the most common cause of ____
Tinea capitis (scalp)
41
Microsporum affects what parts of the body?
Skin and hair
42
Epidermophyton affects what parts of the body?
Skin, nails
43
Another name for tinea pedis
Athlete's foot
44
Tinea unguium (onychomycosis) is common in people with ____
Weakened immune system
45
Which fungi infect subcutaneous tissue (fat)?
- Pseudallescheria boydii
- Fonsecaea pedrosi
46
What does Pseudallescheria boydii cause?
- Mycetoma
- Disseminated disease in immunocompromised patients
47
____ causes chromoblastomycosis
Fonsecaea pedrosi
48
True or false: Candida albicans and Candida auris are multi-drug resistant and cause opportunistic infections
True
49
What is an important and most common predisposing factor for infection with opportunistic fungi?
Broad-spectrum antibiotics
50
Broad-spectrum antibiotics have a dose-dependent exposure, meaning that ____ people may become infected by ____
Healthy/immunocompetent; Large doses
51
True or false: Candida species are common flora of the oral cavity, skin, genital tract, and gut
True
52
Candida are ____ (shape)
Polymorphic (dimorphic)
53
____ form chlamydospores
Candida species
54
What are chlamydospores?
- Spores formed on pseudohyphae in starvation conditions
- Globular structures on hyphal tips (bulb like structures)
55
True or false: only some morphological forms of Candida spp. are important in virulence
False - all forms (polymorphic and dimorphic)
56
____ describes a transition between yeast cells, pseudohyphae, hyphae, and chlamydospores in Candida spp.
Polymorphic
57
____ describes a transition between yeast cells and filamentous mold forms in Candida spp.
Dimorphic
58
Oral candidiasis can take on many forms/severity, such as: (5)
- Pseudomembranous
- Erythematous
- Chronic hyperplastic
- Chronic atrophic
- Angular stomatitis
59
Pseudomembranous oral candidiasis causes:
"Thrush", white lesions easily wiped off
60
Erythematous oral candidiasis is:
Painful, deep **red**, depapillated
61
Chronic hyperplastic oral candidiasis causes:
Confluent white plaques which cannot be removed
62
____ is seen in 60% of denture stomatitis and causes **inflammation** of the mouth and lips in elderly
Chronic atrophic
63
Angular stomatitis is also known as:
Cheilitis or perleche
64
____ causes redness after scraping off pseudomembrane
Erythematous candidiasis
65
What can cause denture stomatitis?
Dentures worn day and night and not cleaned or insufficient oral hygiene
66
____ causes inflammation, cracks, and red patches at the corners of the mouth
Angular stomatitis
67
Chronic mucocutaneous candidiasis causes:
Recurrent **superficial** Candida infections
68
On Sabouraud agar, Candida colonies appear:
Creamy
69
Some strains of ____ are resistant to all available antifungals
Candida auris
70
Candida auris has persistent transmissions in ____
Health care settings
71
____ causes high mortality
Candida auris
72
Name 5 opportunistic fungi pathogens
- Cryptococcus neoformans
- Aspergillus fumigatus, A. flavus
- Rhizopus sp, Mucor sp.
- Pneumocystis jirovecii
- Fusarium sp.
73
Cryptococcus neoformans has a _____ which makes it anti-phagocytic
Gelatinous alginate capsule
74
Where is Cryptococcus neoformans found as a spore?
Pigeon and chicken feces
75
What infections does Cryptococcus neoformans cause?
- Pulmonary
- Meningitis (especially in AIDS patients)
76
True or false: Cryptococcus neoformans infections in AIDS patients is moderately fatal
False - high fatality
77
What is the most common clinical manifestation of Cryptococcus neoformans?
Pulmonary
78
Where is Cryptococcus gattii endemic?
US Pacific NW
79
The DOC for Cryptococcus gattii is amphotericin B. Does it have a good or poor prognosis?
Poor prognosis
80
Aspergillus fumigatus/flavus has what type of hyphae?
Septate hyphae
81
Aspergillus fumigatus/flavus conidia (spores) can be inhaled into ____
Alveolar spaces
82
Aspergillus fumigatus/flavus antigens can cause ____
Hypersensitivity (induce respiratory disorders like allergies and asthma)
83
Aspergillus fumigatus/flavus infection in immunodeficient patients can cause ____
Pulmonary aspergillosis
84
What toxin does Aspergillus flavus produce?
Aflatoxin (mycotoxin)
85
What does aflatoxin cause?
- Acute hepatic necrosis
- Cirrhosis
- **Hepatoma**
86
Aflatoxin is usually found on ____
Peanuts
87
A multistate outbreak of fungal meningitis and other infections occurred in 2012. Which fungi were responsible?
- Aspergillus tubingensis
- Aspergillus fumigatus
88
Which fungi are the most common causes of mucormycosis?
- Rhizopus arrhizus
- Mucor indicus
89
____ are rapid growers (lid pushers)
- Rhizopus arrhizus
- Mucor indicus
90
Rhizopus arrhizus and Mucor indicus can reproduce via:
Sexual (zygospores) or asexual (sporangiospores)
91
____ is a risk factor for mucormycosis
Diabetic ketoacidosis
92
Why is diabetic ketoacidosis a risk factor for mucormycosis?
- Low insulin moves less glucose into cells
- Body burns fat for fuel and makes ketone byproducts
- Ketones make blood more acidic
- Acidosis reduces host defense and allows fungal growth
93
Where does mucormycosis cause disease?
- **Rhinocerebral/rhinofacial**
- lung
- skin
94
True or false: Mucormycosis is aggressive and mortality is up to 95%
True
95
Rhinocerebral/rhinofacial mucormycosis typically occurs in:
- Diabetics in ketoacidosis
- Patients on **steroids** or cytotoxic therapy
96
After eating contaminated food, Mucormysosis spores invade:
- Soft palate
- **Sinuses**
- Cribriform plate
- Brain and behind eyes
97
Pneumocystis jirovecii is an unusual fungus because:
It lacks ergosterol
98
____ has trophozoite and cyst forms
Pneumocystis jirovecii
99
Pneumocystis jirovecii is a major opportunistic pathogen in ____ and presents as ____
AIDS; pneumonia
100
DOC for Pneumocystis jirovecii
Trimethoprim-sulfamethoxazole
101
Fusarium sp. cause infections where?
Ocular (contact lenses)
102
Fusarium sp. infection can become ____ in immunocompromised patients
Systemic
103
Dimorphic fungi grow as ___ at 37 degrees C (body temp)
Parasitic yeast (tissue form)
104
Dimorphic fungi are ____ at 25 degrees C
Mold/hyphal/filamentous
105
Dimorphic fungi cause ____ involving any organ or skin and occur within ____ areas where >80% of population has immunity
Systemic mycoses; endemic areas
106
Histoplasma capsulatum causes ____ infection resembling TB
pulmonary
107
Histoplasma capsulatum is endemic where?
East/midwest
108
Blastomyces dermatitidis causes what disease?
Pulmonary, disseminates to skin and bone
109
Coccidioides immitis is endemic where?
Southwestern US
110
Coccidioides immitis parasitic form
Spherules (thick walled spheres containing endospores); NOT yeast form
111
Sporothrix schenkii causes spores on ____
Rose thorns (Gardeners, rose gardener's disease)
112
After traumatic implantation, Sporothrix schenkii spreads where?
Up arm causing string of abscesses (regional lymphadenopathy, can disseminate)
