Flashcards in 01 Fungus Intro Duncan Deck (39)
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1
What are viruses that attack bacteria called?
Bacteriophages
2
What are the characteristics of Archaea?
Bacteria-like in some respects (size, lack of nuclear membrane); Eukaryote-like in others (DNA and protein structure)
3
What is the Fungal Cell Wall primarily made out of?
Chitin. Hence, insensitive to inhibitors of peptidoglycan synthesis (i.e. B-Lactams)
4
What is an important part of the Fungal Cell Membrane?
Ergosterol. Imparts sensitivity to inhibitors of ergosterol synthesis, activity (e.g. Amphotericin, Azoles, etc.)
5
What are the different Fungal Growth Types?
Yeasts (single cells). Molds - mat of filaments (Mycelium, Hyphae - septate and nonseptate). Dimorphic (Shifts d/t growth situation; e.g. temperature)
6
What is the difference between septate and nonseptate in fungal growth types?
When looking at septate fungus, you can clearly see the different cells connected together. In Nonseptate, cell membranes between cells are dissolved
7
How does Fungal Reproduction occur?
Asexual (budding, conidia). Sexual (mating)
8
What is Fungal metabolism like?
Cannot photosynthesize; therefore must obtain carbon food from the environment
9
What is Chitin made from?
A long change of N-Acetylglucosamine
10
If the Fungal cell wall and cell membrane, what ratio varies with species?
Ratio of Chitin to branched B-Glucan
11
What are some Fungal Toxins and Mycotoxicoses?
Amantin (Amanita mushrooms). Ergot Alkaloids (Grain-infecting fungi (Claviceps), neurotoxicity). Aflatoxin (Aspergillus flavus growth on soiled grains, hepatotoxicity/hepatic cancer)
12
What is used for Fungal Diagnosis?
Microscopic examination (KOH, special stains). Culture (Sabouraud's agar (no bacterial growth)). DNA-based tests. Serologic tests
13
What are the worst Fungal Diseases?
Systemic infections. Opportunistic infections
14
What are the causative fungi for opportunistic infections?
Cryptococcus. Candida. Aspergillus. Mucor, Rhizopus
15
What are the causative fungi for Systemic infections?
Coccidioides. Histoplasma. Blastomyces. Paracoccidioides
16
What is Dermatophytoses?
Cutaneous infections caused by Fungi
17
What types of infections fall under Dermatophytoses?
Athlete's foot (tinea pedis), jock itch (tinea cruris). Ringworm. Dermatophytid: antibody response to circulation fungal antigens - skin lesions
18
Which Fungi are often associated with Dermatophytoses?
Epidermophyton. Microsporum. Trichophyton
19
What are the general characteristics of Subcutaneous infections caused by Fungi?
Slow spreading from site of injury. Rarely becomes systemic, or serious. Granulomatous response (macrophages). Lymphatic involvement
20
What are the different Subcutaneous infections caused by Fungi?
Sporotrichosis. Chromomycosis (lesser importance). Mycetoma (lesser importance)
21
What is Sporotrichosis?
Type of SubQ Infection. Dimorphic Sporothrix. Spread from vegetation, e.g. thorn pricks
22
What is Chromomycosis?
Type of SubQ Infection. Caused from several soil fungi (Fonsecaea, Phialophora, Cladosporium). Spread when cuts are exposed to soil, e.g. gardening
23
What is Mycetoma?
Type of SubQ Infection. Caused from several soil fungi (Petriellidium, Madurella). Spread from soil
24
What are some general characteristics of Systemic Infections caused by Fungi?
Inhalation into lungs. Soil resident mycelial form. Airborne spores inhaled, differentiate into yeasts into the lungs. Assymptomatic, self-limiting (except in immunocompromised: HIV, drugs). Disseminated, serious. Non-contagious
25
What are the steps that Aspergillus go through when inhaled?
Inactive conidia are inhaled. Conidia lodge in lower respiratory tract. Conidia swell and shed outer coat. Conidia germinate into hyphae (blocked by macrophages). Hyphae invade lung and systemic vessels (blocked by neutrophils). If defenses fail, hyphae break off and disseminate to distal organs (blocked by neutrophils)
26
What is Coccidioidomycosis?
Systemic infection caused by Coccidioides immitis. Dimorphic: mold in soil, spherule in infected human tissues. Hyphae form arthrospores that can be inhaled. Endemic in Southern California, AZ, NM
27
What is Histoplasmosis?
Systemic infection caused by Histoplasma capsulatum. Dimorphic: mold in soil, yeast in infected human tissues. Tuberculate macroconidia; microconidia spores transmit infection when inhaled. Thrives in bird droppings. Infects and transmitted by bats; from disturbed bat guano. Develops in macrophages. Mild (most) infections asymptomatic
28
What is Blastomycosis?
Systemic infection caused by Blastomyces dermatitidis. Dimorphic: mold in soil, yeast in infected human tissues
29
What is Paracoccidioidomycosis?
Systemic infection caused by Paracoccidioides brasiliensis. Dimorphic: mold in soil, yeast in infected human tissues. Not typical in US
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