Introduction to Fungus and Mycoses Flashcards
1
Q
Systemic mycoses can all cause?
A
- Pneumonia and can disseminate
- systemic mycoses can form granulomas (like TB)
2
Q
All systemic mycosis are caused by what type of fungi? Exception?
A
- Dimorphic fungi:
- cold = mold
- heat =yeast
- exception is coccidioidomycosis which is a spherule (not yeast) in tissue
3
Q
What are the 4 systemic/ endemic Mycoses?
A
- Histoplasmosis
- Blostomycosis
- Coccidioidomycosis
- Paracoccidioidomycosis
4
Q
What are the different forms of fungi?
A
- Multicellular filamentous structures (molds)
- Unicellular forms (yeast)
- Dimorphic (either form depending on conditions such as temperature and environment)
5
Q
Fungal cell membrane made up of ? Cell wall?
A
- Membrane= sterols
- Cell wall=chitin
6
Q
How does fungi cause disease?
A
- Both direct invasion and host immune response
- (NO toxins released)
7
Q
How do yeast cells reproduce?
A
-
budding
- buds are called blastoconidia
8
Q
Definition of Hyphae? Mycelia?
A
- Hypahe: Continuous multinucleated non-septated/septated protoplasm
- Mycelia: cluster of hyphae
9
Q
Sexual reproduction of fungus occurs via? Example?
A
-
Sporangia:
- sporangiophore with sporangium and sporangiospore;
- spores inside are what get inhaled;
- spores have to germinate and form new fungus
- sporangiophore with sporangium and sporangiospore;
- ex: Rhizopus species
10
Q
Asexual reproduction of fungus occurs via? Example?
A
- Conidia: with conidiospore
- ex: Aspergillus species
11
Q
- Histoplasmosis is found in?
- What part of country?
A
- Found in soil enriched with bird and bat poop
- Mississippi and Ohio river valleys
12
Q
What cell can Histoplasmosis hide in?
A
Macrophages
13
Q
- How is Histoplasmosis transmitted?
- What does it cause?
A
- Inhalation
- Acute and chronic pulmonary disseminated disease
- (AIDS)
- mucosal ulcer
14
Q
All endemic/ systemic mycosis have what as primary source of infection?
A
Lung
15
Q
Where is the geographic region that Blastomycosis is found?
A
- Mississippi river valley
- southeastern states
- north-central states
16
Q
What is primary site of infection of Blastomycosis? What does it cause
A
- Inhalation (lungs)
-
Causes:
- Skin lesions
- pulmonary disease
- disseminated infection (can reach the blood); form granulomatous nodules
17
Q
What is geographic region that Coccidiomycoseis is found?
A
Southwestern United States, California
18
Q
- Coccidioidomycosis causes?
- When does the case rate increase?
- What are the spherules filled with?
A
- Pneumonia and meningitis (pulmonary disease, 40% flu like)
- Case rate increases after earthquakes
- spores in dust are thrown in the air and inhaled —> spherules in lung filled with endospores
19
Q
Where is Paracoccidioidomycoseis found?
A
-
South America
- similar features to Coccidioidomycosis (dimorphic)
20
Q
What endemic/systemic mycoses are most common in cellular immunity deficiency?
A
- Disseminated histoplasmosis and coccidiomycosis
21
Q
What are 5 opportunistic fungus?
A
- Pneumocystosis
- Mucormycosis (Mucor and Rhizopus spp.)
- Aspergillosis
- Cryptococcosis
- Candidiasis
22
Q
Candida albicans has what form?
A
Dimorphic forms pseudohyphae and oval budding yeasts
23
Q
Candida albicans causes what type of infection? Especially in which patients?
A
- Systemic or superficial fungal infections
- vagina, mouth, tongue, diaper rash
- especially in immunocompromised patients have oral esophageal thrush
24
Q
Cryptococcosis neoformans has what type of form? Virulence factor
A
- Heavily encapsulated yeast (capsule “crypt”)
- has halo appearance
-
virulence factor:
- antiphagocytic polysaccharide capsule
25
Where is Cryptococcosis neoformans found and how is it acquired?
* Found in soil, pigeon droppings
* Mississippi River Valley and eastern states
* acquired through **inhalation**
* dissemination to mininges (brain)
26
How does Cryptococcosis most commonly present as?
* **Chronic** **meningitis**
* Lung and brain infection
* acute pulmonary infections
27
What groups are at risk for Cryptococcosis infection?
* T cell abnormalities:
* **HIV**
* hematologic malignancy
* organ or bone marrow transplant
* corticosteroids or other immunosuppressive drugs
28
*Aspergillosis* have what kind of form?
* V shaped hyphae that branch at a 45 degree angle
* mold produces **conidia** **in radiating chains** at end of conidiosphore
29
How is Aspergillosis acquired?
* Acquired by inhalation;
* lung= primary site of infection
* (**common environmental mold**)
30
What does Aspergillosis cause?
* **angioinvasion** (lung and CNS)
* hemorrhage and tissue infarction,
* especially in the **lungs**
31
* Mucormycosis (Rhizopus, Mucor spp.) hyphae form?
* Where is it found?
* Common environmental mold
* Ribbon like hyphae with wide angle branching (90 degrees)
32
Mucormycosis cause disease mostly in what patients?
* angioinvasion in:
* immune suppressed patients
* or diabetes (**especially diabetic ketoacidosis)**
33
Pneumocystosis has what form and how does it enter host?
Yeast-like and it is inhaled
34
* Pneumocystosis infection is predisposed in what patients?
* What does it present as?
* **Immunocompromised**,
* e.g. AIDs
* _Presents_ _as_:
* pneumonia with hypoxia (pneumocystis pneumonia)
35
Sporotrichiosis is caused by which fungus? What is form?
**Sporothrix schenckii**
* dimorphic fungus
36
* Where is sporotrichiosis found
* Route of infection?
* Clinical manifestation?
* Found in soil, moss, decaying vegetation **(problem for gardeners)**
* from thorn prick, rose garden
* cause cutaneous ulcer
37
Mycetoma is found mostly where? Clinical manifestation and treatment?
* **Tropics**
* Chronic granulomas with discharge (affects subcutaneous tissues)
* Tx: surgical extirpation
38
Dermatophyte infections is caused by what 3 genera?
1. Trichophyton
2. Microsporum
3. Epidermophyton
39
What parts of body does a Dermatophyte infect?
1. Stratum corneum
2. hair shafts
3. nails
40
Dermatophyte infections cause?
* Tinea corporis (body); ringworm
* Tinea pedis (feet); athletes foot
* Tinea capitis (head)
* Tinea cruris (crotch); jock itch
* Tinea unguium (nails)
41
What is a superficial mycoses?
* ***Malassezia*** sp.
* Normal colonizers of stratum corneum
* M. furfur:
* Tinea versicolor
* M. globosa:
* seborrheic dermatitis
42
Organism feature of Blastomycosis?
Dimorphic BBB- broad based budding
43
What are two risk population for Candidiasis?
1. Immune suppressed patients
2. Chronic granulomatous disease
44
What is route of infection of Candidiasis?
Mucous membranes
45
Where is Candidiasis normally found?
* Normal flora of skin, mucous membrane, GIT
* **opportunistic**
46
What population is at risk for infection by Aspergillus?
Immune compromised
47
Route of infection of mucormycosis?
Inhalation
48
Chromoblastomycosis found where? Clinical manifestation/ people at risk?
* Found in tropics and subtropics
* Problem for people who spend more time outdoors
* Cause slow forming lesions resulting in epithelial hyperplasia, fibrosis
49
Where are dermatophytes normally found?
Direct contact with infected host or exfoliated skin
50
Who is more at risk of Malassezia sp. infection?
* young adults in hot weather
* cause:
* tinea versicolor (hypo/hyper pigmentation)
* seborrheic dermatitis
