1. Intro to Mycology

What is the definition of a primary pathogen? And ~ how many are there?

pathogen that can cause disease in a healthy host

~20

What are the 4 statements regarding funal-human interaction?

1. humans are non-essential for fungal life cycle

2. healthy adults generally not susceptible to fungi

3. some activities could predispose to infection

4. all statements have an exception

What are the 4 general characteristics of fungi?

eukaryotic, thick cell wall, mostly obligate aerobe (depend on O₂), prefer neutral or slightly acidic pH

What are the cells walls of fungi made of and what makes them special?

made of chitin

allows for absorbance of special dyes

What type of cells are yeasts?

single vegetative (smooth, creamy, bacterial-like colony w/out aerial hyphae)

How are yeasts primarily ID’ed?

based on biochemical testing & molecular diagnostic

How do yeasts reproduce? What is the most common form of reproduction called?

Via budding or fission

blastoconidia

What is the main body of molds made of? What are the 2 forms of that body?

mycelia (root like network) made of hyphae (thread-like tubes)

vegetative & aerial

What are the 4 shapes of hyphae?

antler, racquet, spiral, rhizoid

What is the difference between septate vs aseptate hyphae?

septate has cross walls, aseptate has infrequent cross walls

What is the difference between hyaline vs phaeoid hyphae?

hyaline: non or light-pigmented hyphae

phaeoid: also dematiaceous, darkly pigmented

What are the 2 phases of a dimorphic fungi?

mold @22-25 C

yeast @37 C w/ increased CO2

What is a polymorphic yeast?

Can form yeast & mold in same culture

Generally yeast first then mold

What are the asexual reproduction parts for mold?

conidia

phialides: vase-like structure that produce phialoconidia

annellides: ringed structures that produce annelloconidia (thing segmented like worms)

What are the anatomical parts of aspergillus (uniseriate vs biseriate)

both have (bottom top): foot cell, conidiophore, vesicule, phialide, conidia

biseriate has a metula that holds 2x phialids

What is an arthroconidia?

Forms spores directly from the hyphae

What is the difference between teleomorph & anamorph?

teleomorph: sexual reproductive stage of a fungi

anomorph: the asexual reproductive stage of the same fungi

synanomorph: when a fungi has multiple distinct anamorphs

What is formed as a product of teleomorph?

zygospore

What are the four groups of clinically significant fungi?

Phylum ascomycota

Phylum Basidiomycota

Subphylum mucoromycotina (mucorales)

Form division fungi Imperfecti (deuteromycota)

What are the sexual spores unique to phylum ascomycota?

Ascospores (contained in a saclike cell called the ascus)

What is the only pathogenic basidiomycota?

The sexual form of cryptococcus neoformans (filobasidiella neoformans)

What are some other genus of basidiomycota?

malassezia & trichosporon

What are some unique characteristics of mucorales? (4)

rapid growers, gray to white aerial mycelium, aseptate, opportunistic pathogens

What type of reproduction do mucorales undergo? What are the sexual spores unique to mucorales?

asexual

sporangiophore & sporangiospore

What organisms get placed under Fungi Imperfecti (Deuteromycetes)?

organisms when no mode of sexual reproduction has been identified

What are the 4 anatomical categories of mycoses (fungi causing disease)?

superficial, cutaneous, subcutaneous, systemic

What are fungi that degrade keratin called? And what category do they fall under?

dermatophytes

superficial & cutaneous mycoses

What are some superficial mycoses symptoms?

tinea (ringworm)

tinea versicolor (discoloration & scaling of skin)

tinea nigra (black/brown rash)

piedra (stones)

What are some cutaneous mycoses symptoms?

itching, scaling skin

thickened discolored nails

brittle broken hairs

What generally does NOT occur in subcutaneous mycoses?

dissemination through the blood

What the 3 clinical features of subcutaneous mycoses?

chromoblastomycosis (nonhealing ulcers)

eumycotic mycetoma (draining sinus tracts)

lymphocutaneous infection