Fungi Flashcards
(29 cards)
Fungal characteristics
eukaryotic, heterotrophs
possess a chitinous cell wall with beta(1,3) and (1,6) glucans, mannose modified proteins and GPI- anchored proteins
ergosterol in cell membrane
produce filamentous structures and spores
Dimorphic fungi
exist as 2 different forms depending on temp
heat (35-40)-yeast, cold (<30)-mold
includes blastomyces dermatidis, coccidiodes immitis, histoplasma capsulatum and paracoccidioides brasiliensis
Virulence factors
thermal dimorphism, toxin production, capsules and adhesion factors, hydrolytic enzymes, inflamm stimulants
fungal disease classification
hypersensitivity
mycotoxicoses
mycetismus
infections
systemic classification
ascomycota
basidiomycota
zygomycota
mitosporic fungi
Ascomycetes
form sexual spores in an ascus, largest fungal phylum
septate fungi
candida albicans, pneumocystis jirovecii, trichophyton rubrum/mentagrophytes
basidiomycetes
form sexual spores on surface of a pedestal- basidium
cryptococcus neoformans
Zygomycetes
most primitive fungal phylum forming spores as zygosporangium
Aseptate fungi with right angle branching
Mucor spp, rhizopus spp, absidia app
Superficial mycoses
colonization of outer layers of skin, hair, nails
malazzezia furfur- pityriasis Versicolor
Hortae werneckii- Tinea Nigra
Piedra Hortae- Black Piedra
Trichophyton Rubrum and Mentagrophytes (Ascomycete)- onchomycosis
Cutaneous Mycoses
macular, papular or pustular lesions that itch and spread from scratching; due to soil organisms introduced into extremities via trauma
Tinea barbae- beard tinea pedis- athletes foot tinea- crusis tinea corporsis- trunk tinea capitis- scalp
Subcutaneous mycoses
Sporothrix schenckii- asomycete- sporotrichosis, mycetoma/eumycetoma, chromoblastomycosis
opportunistic mycosis
cause disease in immunocompromised ppl
candida albicans- ascomycete- candidas aspergillus- ascomycete cryptococcus neoformans- basidiomycetes rhizopus, absidia, mucor- zygomycete pneumocystis jirovecii- ascomycetes
candida albicans
opportunistic ascomycetes with pseudohyphae
superficial skin infection, oral cavity, genitalia, LI- forms off white pasty colony with yeasty odor
causative agent of oral thrush, vulvovaginal yeast infection and cutaneous candidiasis
gram positive
Aspergillus
opportunistic ascomycetes with low angle branching hyphae, septate
common airborne soil fungus infecting the lungs
AIDS, leukemia, transplant pts
cryptococcus neoformans
opportunistic basidomycetes
inhaled, inhabits soil around pigeon roosts infecting lungs and othe rograns like brain
AIDS,cancer,diabetes
use bird seed agar
Rhizopus, absidia, mucor
opportunistic zygomycete
saprobic fungi found in soil, water, organic debris and food
usually harmless but can invade nose, eyes, heart, brain and ppl with diabetes or malnutrition
pneumocystic jirovecii
opportunistic ascomycetes
small unicellular fungus that causes PCP, can be rapidly fatal
AIDS
Sporotrichosis
subcutaneous ascomycete
sporothrix schenckii
subacute or chronic granulomatous infection often infecting lymphatics
rose bush penetrates skin-> lesion-> ulcerates-> spreads to lymph
mycetoma/eumycetoma
subcutaneous ascomycete
sporothrix schenckii
granulomatous infection- extends from subcutaneous to bone
pigmented nodules may drain through sinuses and produce grains
Chromoblastomycosis
subcutaneous ascomycete
sporothrix schenckii
warty pigmented lesions which grow outward from site of introduction “cauliflower lesion”- darker reddish in color
Malassezia furfur
superficial mycoses
pityriasis/tinea versicolor
infects and causes hypo/hyperpigmented skin
fluoresces under UV
hortea werneckii
superficial
tinea nigra- causes skin to darken
piedra hortae
superficial
black piedra- infects hair shaft- also called white piedra
trichophyton rubrum/mentagrophytes
superficial ascomycete
onchomycosis
infects fingernails and toenails
degenerates keratin/keratinolytic
