P1 Flashcards
Published Les Teignes; father of Medical Mycology
Raymond Saboraud
multicellular members of the plant kingdom and are referred to as thallophyte
usually filamentous- branched- somatic structure surrounded by the true cell wall
Fungi
5 characteristics of fungi
- achlorophyllous
- ubquitous
- saphrophytes
- grows in an acidic environment
- resistant to cold and are easily killed by high temp
2 basic fundamental structures of fungi
hyphae and spores
2 morphologic forms of fungi
yeast and mold
produce moist, creamy opaque, or pasty colonies (0.5-3.0 mm)
yeast
single-celled/unicellular structures with a thick cell wall
most reproduce by asexual budding, few by binary fission
yeast
multicellular filamentous colonies; filamentous colonies: fluffy, cottony, wooly or powdery
mold
the basic structural unit of mold
hyphae
hyphae can be divided into: (3)
septate, aseptate or coenocytic, and mycelium
morph:
curved, freely branching and antler in appearance
antler hyphae or favic chandelier
enlarged, club shaped with the smaller end attached to the large end of the adjacent club-shaped strands
racquet hyphae
coiled or corkscrew seen within hyphal strands, frequently found in dermatophytes
spiral hyphae
capability of an organism to grow MORE THAN ONE form under different environment
ex. Sporothrix schenkii
Dimorphic fungi
perfect fungus; is associated with the formation of specialized structures that facilitates fertilization and nuclear fission resulting in the formation of specialized spores
sexual (teleomorph)
fusion of identical cells
zygospores/zygomycetes
enclosed in a specific sac called ascus (asci)
ascopores/ascomycetes
fusion of non-identical cells from the same hyphae
oospores
fungus imperfecti; seen in most fungi
asexual (anamorph)
derived from the cells of the thallus or body of the fungi
thalospores
give examples of species that belonged to blastospores
Candida albicans, Cryptococcus neoformans
buds formed by the budding process, sprouting from the surface of the parent cell
blastospores
arise by fragmentation of the ends of hyphae at the point of septation; SQUARE BARREL-SHAPED thick walled cells
arthospores/arthroconidia
hyphal cell SEPARATE from one another to form flat ended spores
ex. Geotrichum candidum
Oidia
enlarged, round unicellular, thick-walled structures that are formed during unfavorable conditions; formed by the enlargement of a hyphal cell
chlamydospores/chlamydoconidia
3 types of chlamydospores/chlamydoconidia
terminal, intercallary, sessile
born internally within the sac called “sporangium” which develops at the tip of the sporangiophore
sporangiospores
asexual spores produces singly or in groups by specialized branched called conidiophore
Aspergillus and Penicillium
conidia
small, unicellular conidia, round, pyriform, or pear-shaped
microconidia or microaleriospores
large, multicellular, multi-septate, clavate or spindle shaped
echinulate-rough and spiny
macroconida/mmacroaleriospores
in this medium, observe for: hyphae, budding yeast cells or any mycelial filaments
KOH
for identification of Cryptococus neoformans
look for ENCASULATED yeast cells
follows NEGATIVE staining
India ink
-uses AMAN medium
-preserves and stains fungi (shades of blue)
-contains lactic acid, phenol and cotton bue
-observe for spores, yeast cells and hyphae
Lactophenol Cotton Blue
uses flourescence (2)
calcaflour white, wood’s lamp (bright yellow green under UV light)
all fungi in Gram stain are:
positive
best for visualizing fungi in skin scraping or tissue; if dematiaceous, appears brown or black
PAS
-gridley, gomori-methenamine silver
-H. capsulatum
Wright stain or Giemsa
best stain for Blastomycosis dermatitidis
Papanicolau
ideal for Tinea versicolor
acridine orange
-useful in the diff. og Nocardia fro Actinomyces
- Nocardia are acid-fast
Acid fast stain
state the diseases that belonged to superficial mycoses: (6)
- keratomycosis (keratitis/keratomycosis)
- otomycosis (mycotic otitis externa)
- pityriasis versicolor
- tinea nigra
- black piedra
- white piedra
What is the etiological agent of Pityriasis versicolor?
Malasezzia furfur
Provide the disease
-spaghetti and meatballs appearance
-hypopigmented macules
Pityriasis versicolor
Provide the disease and the etiliogical agent:
-black macules
-black, 2-celled oval yeasts in skin scrapings
Tinea nigra; Exophiala wernickii
Disease and etiologic agent:
-black NODULES on HAIR shaft composed of spore sacs and spores
Black Piedra; Piedraia hortae
-major cause of blindness
-white corneal plaques with the development of satellite lesions and endothelial plaques
-common with contact lens users
Keratomycosis
Yeast: yeast cells with strands of pseudohyphae
Filamentous: clear septate hyphae
Keratomycosis
Binds to ergosterol in fungal cell membranes and cause the membrane to become leaky
Polyenes
Amphotericin B, Natamycin
Polyenes
inhibits CYP P450 14-a demethylase enzyme involved in the conversion of lanosterol to ergosterol
Azoles: Ketoconazole, Fluconazole, Voriconazole
causes faulty RNA synthesis and non-competitive inhibitor of thymidylate synthesis
Pyrmidines: Flusytosines
Ergosterol Biosynthesis inhibitor
Allylamines; Terbinafine
Cell wall and D-glucan synthesis inhibitors
Echinocandins: Capsofungin, Micafungin
chronic fungal infection of the outer ear canal
otomycsis/ mycotic otitis externa
other name of piedras:
chignon disease, tinea nodosa, biegel’s disease
-occurs on scalp
-Piedraia hortae
-black nodules resembling nits of lice
-septate dematiaceous hyphae
-open nodules containing OVAL ASCI with 8 ascospores
BLACK PIEDRA
-facial and genital hairs
-Trichosporon beigelii
-white nodules larger and softer
-septate and dematiaceous
-tend to break in ARTHOSPORES
WHITE PIEDRA
other names of Tinea nigra:
Keratomycosis nigricans palmaris/ Tinea nigra palmaris/ Pityriasis nigra/ Microsporis nigra
-superficial inffection on the palm of the hands or the sole of foot
-KOH: strongly dematiaceous septate hyphae
Tinea nigra
Etiologic agent of Tinea nigra:
Cladosporium wernickii or Hortae or Exophiala or Phaeoannellomyces werneckii
-patchy brown desquamating rash involving mainly the trunk, arms, shoulder and facee, “blotchy” appearance
- “spaghetti and meatbballs appearance”
Pityriasis versicolor
what was the first fungi that was described by Leber that causes Keratomycosis
Aspergillus spp.
keratin as a source of nitrogen but are usually INCAPABLE of penetrating the subcutaneous tissues
Cutaneous mycoses/Dermatomycoses
-ringworm infection of the inguinal area
-jock itch
Tinea cruris
feet- athlete’s foot
Tinea pedis
Scalp ringworm
Tinea capitis
Barber’s itch
Tinea barbae
affects hair and skin
Microsporum
affects the hair, skin, and nails
Trichophyton
affects the skin and nails
Epidermophyton
-nail (onchomycosis)
-most often due to Trichophyton rubrum and T. interdigitale
Tinea unguim
Tinea manus is infection affecting what part of the body?
Hand
Treatment for Tinea corporis
Topical azole
-ECTOthrix
-yellow green fluorescence except M. gypseum
Microsporum
-anthropophilicc
-GR: 2 weeks
Microscopic ID: sterile hyphae, TERMINAL chlamydospore, FAVIC chandelier, and pectinate bodies
Microsporum audonii
Colony: downy white to salmon pink
Microsporum audonii
-zoophilic
-caused of ringworm in dogs and cats
-GR: 1 week
-Colony: white and fluffy; reverse canary yellow pigment, BOAT SHAPED
-8-12 septa
Microsporum canis
-geophilic
-GR: 1 week
-Colony: Mold and cottony light brown “cinnamon powdery” color
Microsporum gypseum
Differential medium for M. gypseum and M. canis (+)
Rice medium
-anthropophilic
-GR: 1 week
-“BAMBOO” hyphae
Microsporum ferruggineum
-worldwide cause of athlete’s foot
- urease (+) in CHRISTENSEN MEDIUM
- GR: 7-10 days
- Macroconidia:CIGAR SHAPED
- Microconidia: engrappe
Trichophyton mentagrophytes
COLONY: White to pinkish granular and fluffy varieties
-CATTLES
- V-shaped penetration on hair shaft (+)
Trichophyton mentagrophytes
-caused of long established foot and toe nail infections
-FASTEST growing dermatophytes
-GR: 2 days
-UREASE (-)
- v-shaped penetration on hair shaft (-)
T. rubrum
Macrroconidia: pencil shape
Microconidia: “tear-drop”
Colony: white to pink granular; UGAL folds are common
Yellow-Wine red
Trichophyton rubrum
Differential medium; aids in the identification of T. rubrum (-) and T. mentagrophytes (+)
Dextrose Cornmeal Agar
-anthropophilic EXCEPT T. verrucosum
-ecto or endothrix
- NO FLUORESCENCE in wood’s lamp
Trichophyton
-Tinea imbracata
- Concentric/ring shaped in appearance
- ballon shaped chlamydoconidia
Trichophyton concentricum
- adult ringworm of the scalp (ALOPECIA)
- GR: 7-10 days
- Macroconidia: “balloon” forms
- Microconidia: “tear-drop” club shaped with flat buttons
- Colony: white, tan, yellow or rust, SUEDE-LIKE to powdery
Trichophyton tonsurans
- found in cattles
- grows better at 35 degrees
- 2-3 days
- Macroconidia: rare; RAT TAIL
- Microconidia: “tear-drop”
- NOT ANTROPOPHILIC
Trichophyton verrucosum
- 2-3 weeks
- BRANCHED TORTOUS HYPHAE
- chlamydospore are usually aligned in chains
- Colony: PORTWINE to deep VIOLET
Trichiophyton violaceum
SLOWEST growing dermatophyte
2-3 weeks
hyphae seen as “FAVIC-CHANDELIERS”
Colony: irregular heaped, smooth white to cream colony with RADIATING GROOVES
Trichophyton shoenleinii
COLONY: center is folded, and is KHAKI GREEN, periphery is yellow
“CLUB-SHAPED” macroconidia
no microconidia
Epidermophyton floccosum
heterogenous group develop at the site of transcutaneous trauma
SUBCUTANEOUS MYCOSES
heterogenous group develop at the site of transcutaneous trauma
SUBCUTANEOUS MYCCOSES
Only fungus disease that can almost be diagnosed by clinical picture alone
Dimorphic
Yeast: Cigar shaped
Methenamine Silver Stain: “ASTEROID BODIES”
ROSETTE, DAISY-LIKE, BOUQUET LIKE
old-mold: sleeve formation
Sporotrichosis/ Rose Gardener’s Disease
Etiologic agent of sporotrichosis
Sporothrix schenkii
-warty tumor-like lesions
-“CAULIFLOWER LIKE’
Chromomycosis/Chromoblastomyosis/Verrucous dermatitidis
Three Chromomycosis types:
Cladosporium, Phialopphora, Acrotheca