B3-088 - Fungi Flashcards
Germ Tube
tube-like outgrowth that is beginning of a hypha
Pseudohyphae
chain of cells produced when buds fail to disassociate; constricted at septa (sausage like)
Hypha
long, branching, filament-like structure that fungi use for vegetative growth
Arthroconidia
fungal spores produced by segmentation/breakup of hyphae; usually barrel-shaped or rectangle
Four methods to diagnose Mycoses
Direct microscopic examination of specimens
Culture
Serology
Direct Molecular detection
Three genera of superficial fungal infections
Microsporum - macro- and microconidia
Trichophyton - microconidia
Epidermiphyton - macrocondia
Tinea group
aka ringworm (no worms involved)
Tinea barbae
beard areas of face and neck
Tinea capitis
scalp and hair shaft
Tinia corporis
skin on body - usually trunk
Tinia cruris
groin, perineum (between pp and booty), perianal
Tinea manuum
hands
Tinea pedis
foot
Tinea unguium
nails
Dermatophyte Transmission
Person-to-person
Gym, locker rooms
animal to person
soil to person
Touching something infected
HIGHLY CONTAGEOUS
Dermatophyte Symptoms
Itchy, red, raised, scaly patches
Blistering, oozing
Ring appearance, more red outside then center
May impact skin pigmentation
Scalp/beard: bald patches
Nails: discolored, thick, crumbling
Dermatophyte diagnosis
Based on appearance of skin
KOH test
Culture
Wood’s light
KOH Test
Skin scraping are dissolved in KOH and examined under microscope - KOH dissolves the keratin material so the fungi can be seen clearer
Wood’s light
UV light
Helps diagnose tines wapitis since hair fluoresces when infected with fungus
Opportunistic Systemic Mycoses
Candidiasis, Cryptococcosis, Aspergillosis, Mucormycosis (Zygomycosis)
Mucormycosis organisms
Rhizopus, Mucor, Rhizomucor, Lichtheimia (Absidia)
Often called “Zygomycetes” but correct term is “Mucorales”
Where is Mucormycosis found
ubiquitous in the environment
found in soil and decomposing matter (bread molds)
Clinical correlation necessary (pathogen or contaminant)
Mucormycosis Transmission
Inhalation of spores
Cutaneous or Subcutaneous inoculation
Ingestion causing GI disease
Mucormycosis Risk factors
Diabetic ketoacidosis
Chemotherapy
Transplantation
Injection drug use
Mucormycosis Clinical complications
Pulmonary
Rhinocerebral (nose to brain)
Cutaneous
Disseminated
VERY high mortality
Mucormycosis Diagnosis
Culture
Direct exam
Histopathology
Mucormycosis Hyphae
Large, wide, ribbon-like, pauciseptate branching hyphae
Mucormycosis colonies
Wooly, rapid growing, LID LIFTERS
Aspergillosis organisms
A. fumigatus: most common (90-95%)
A. niger: aspergilloma
A. flavus: produces disease in leukemic patients
Where is Aspergillosis found
Ubiquitous in the environment
Commercial uses: used to ferment rice to make sake
Aspergillosis transmission
inhalation, traumatic implantation
Aspergillosis risk factors
Neutropenia, corticosteroids, cytotoxic drugs
Aspergillosis Mycology
septet hyphae, acute angle branching
Grows rapidly
Aspergillosis Risk factors
CF
Asthma
Severely immunocompromized
Aspergillosis diagnosis
Main: Culture, Histopathology
Serologic test for antibody, galactomannan detection, molecular tests
Candidiasis organisms
C. albicans
C. glabrata
C. parapsilosis
C. tropicalis
C. krusei
Where is Candidiasis found
Ubiquitous in the environment
Normal flora of skin, GI, GU, oropharyngeal
Candidiasis Transmission
Normally endogenous in origin
Breakdown of mucosal membranes
Candidiasis Risk factors
Neutropenia, AIDS, abdominal surgery, prolonged use of Abx, immunosuppressive therapy, IV catheters, prosthetic devices, long ICU stays, renal failure
Candidiasis Mycology
Budding yeast, pseudohyphae, hyphae
Candidiasis Culture
White - buff, pasty
Rapid growth (1-4 d)
Produces some feet
Candidiasis Germ Tube
C. albicans produces GT within 2-3 of incubation in serum