FUNGI Flashcards
Each of the following fungal genera cause dermatophytosis except one:
a. blastomyces
b. Microsporum
c. trichophyton
d. Epidermophyton
blastomyces
What is a dermatophyte?
pathogenic members of the keratinophilic (keratin digesting) soil fungi.
T/F The dermatophytes Microsporum and Trichophyton are human and animal pathogens
True
T/F The dermatophyte Epidermophyton is a animal pathogen
False, is human pathogen
What are arthrospores
asexual spores formed in the hyphae of the parasitic stage
what are conidia
sexual or asexual spores formed in the “free living” environmental stage
in regards to dermatophytes; infections occur by contact with ______ or _________
arthrospores or Conidia
Describe the process of infection of dermatophytes
Infection usually begins in a growing hair or the stratum corner of the skin. Dermatophytes do not generally invade resting hairs, since the essential nutrients they need for growth are absent and limited. Hyphae spread in the hairs and keratinized skin, eventually developing infectious arthrospores
in humans, dermatophytoses are referred to as:
tinea infections; are named with reference to the area of the body involved.
Tinea corporis in children is
often the result of tinea capitis infection that has spread to the face; represents how infections can spread
Tinea capitis:
most often seen in children, is a dermatophyte infection of the hair and scalp
tinea corporals (ring worm)
occurs on the trunk, extremities, and face
Tinea barber is
an infection of the hairs and skin in the beard and mustache area, and is usually seen in men
Tinea faciei
is seen on the nonbearded parts of the face
Tinea cruris
is an infection of the groin. commonly called jock itch
Tinea pedis (athlete foot)
is an infection of the foot
Tinea Manuum
Dermatophyte infection of one or occasionally both hands
Tinea unguium
dermatophyte infection of the nail
The most effective antimycotic (anti fungal agent is
griseofulvin (although griseofulvin is prescribed to treat infections of the skin, it cannot be applied as a cream and must be taken in pill form
Describe Fungi
are eukaryotic, have a complex cell wall, are all gram positive, grow in sabouraud medium and contain both DNA and RNA
What are the two types of Fungi:
yeasts and molds
describe yeasts:
grow as single cells that reproduce by asexual budding
describe molds:
Long filaments (hyphae) which form mat-like structure that is referred to as mycelium
what is dimorphism?
characteristic of some fungi, meaning they form different structures at different temperatures (i.e exist as molds in saprophytic, free-living state at ambient temperatures and as yeasts in host tissues at body temperature)
What are the major dimorphic fungi?
Blastomyces, histoplasma, coccidioides, and sporothrix schenckii
Must fungi reproduce asexually by forming _____ from the sides or ends of specialized structures called ________.
Conidia (asexual spores); conidiophores
*different conidia help identification of fungi
Examples of asexual spores (conidia);
arthrospores, chlamydospores, blastospores, and sporangiospores
Some fungi reproduce sexually by mating and forming:
sexual spores (examples zygospores, ascospores, and basidiospore)
All fungi, except for those belonging to the class zygomycetes are ___
septated
the cell walls of most fungi contain
chitin and beta-1:3-linked gluten
sterols (ergosterol) are in ____. most anti fungal agents target this component of fungal cell membranes
cell membranes
Fungal infections generally initiate a _______ delayed hypersensitivity reaction
type IV
The formation of ______ in response to fungal infection is common
granulomas (seen in coccidioidomycosis, histoplasmosis, blastomycosis, etc)
