Blakes Mycology flashcards
Saprobes
An organism esp a fungus that lives on decaying organisms
Dimorphisms
Existing in two forms
Two phases
- yeast or yeast like
Filamentous forms
Teleomorph=
What type of spores
Sexual form
- Ascospores
Ascospores
sexual spores contained within a ascus
Anamorphic=
What type of spores
Asexual
- conidia-asexual spores
Conidia
Asexual spores
Synanomorphs=
More than one asexual form of a fungus
Yeast
- Unicellular
- Budding= occurs by a process called outpouching
Budding
Occurs by a process called outpouching
Germ tubes
Incomplete cell division (the initial stage of true hyphae formation)
- outpouching of the cell wall that becomes tubular but does
not have a constriction
Hyphae-
long filamentous structure (tube, frequently
branching)
Mycelium
Mass or network of hyphae
Vegetative hyphae
Anchors the molds and absorbs nutrients
Reproductive hyphae
Hyphae with reproductive structures
Vegetative mycelium
Network or mass of vegetative hyphae
Aerial mycelium
Mycelium that grows upward or outward from the substrate
Septate
have dividers between the cells—have pores that
allow cytoplasm and nutrients to flow through
Sparsley septate
Non-septate
Hyphae cells do not have septa to divide them or
septa are rarely observed
Hyaline
Non-pigmented hyphae
dematiaceous
Dark pigment or melanized
Four categories of mycoses
- Superficial cutaneous mycoses
– Infection of hair, skin, or nails
– No invasion of deeper tissues - Subcutaneous mycoses
– Beneath the skin, but not systemic - Systemic mycoses
- Opportunistic mycoses
Superficial cutaneous mycoses
Infection of hair, skin, or nails
– No invasion of deeper tissues
Subcutaneous mycoses
Beneath the skin, but not systemic
four of superficial fungi
- Superficial – skin, nails, & hair shaft
- Tinea
- Piedra
– Piedraia hortae
– Trichosporon beigelii - Candidosis
- Dermatophytes
– Trichophyton
– Microsporum
– Epidermophyton - Pityriasis versicolor: Malassezia furfur
types of Peidra
-Piedraia hortae
– Trichosporon beigelii
Dermatophytes
– Trichophyton- hair. Skin, and nails
– Microsporum- hair and skin
– Epidermophyton- skin and nails
Pityriasis versicolor causes
Malassezia furfur
Malassezia furfur
Multiple asymptomatic scaly patches varying in color from white to tan to brown to pink
Mycoses
A disease caused by a fungus
Black piedra is caused by
Peidraia hortae
white piedra is caused by
Trochosporon beigelii
Cutaneous layers
skin, hair nails
* Keratinized layer
* Dermatophytes
–Trichophyton, Epidermophyton,
Microsporum
Tinea causes what
(Ringworm) –
caused by
Dermatophytes
Tinea barbae
Beard ringworm
Tinea Mannum
Hands ringworm
Tinea capitis
Scalp or head ringworm
Tinea pedis
Feet ( athlete foot)
Tinea corporis
Body
Onychomycosis
Tinea unguium ( nail infection)
Trichophyton rubrum
Causes Tinea corporis, -capitis, -unguium, and -barbae
Microconidia-
Small asexual spores
Microsporum gypseum
Tinea
capitis and corporis
Microsporum canis
- Tinea
corporis,
tinea capitis,
tinea barbae,
tinea
manuum
Epidermophyton floccosum
Tinea cruris- of the genitals
tinea pedis,
tinea
corporis,
onychomyco
sis
Subcutaneous-
- deeper layers
- Chromoblastomycosis
– Chronic fungal infection of the skin and the
subcutaneous tissue
– Traumatic inoculation of a specific group of
dematiaceous fungi
– Non-healing ulcers
Chromoblastomycosis
Causes brown coloration of skin
Agents of chromoblastomycosis
– Fonsecaea pedrosoi
– Phialophora verrucosa
– Cladophialophora carrionii
– Rhinocladiella aquaspersa
Chromoblastomycosis signs and symptoms
- Brown-pigmented, wart-like lesions
- Verrucous, “cauliflower-like” dermatitis
- Common in tropical and subtropical countries
- Usually as a result of trauma
- Secondary bacterial infection is common
Verrucous
Cauliflower like dermatitis
Sporothrix
- Sporotrichosis, also known as rose
gardener’s disease, a chronic infection
caused by the saprophytic dimorphic
fungus Sporothrix schenckii. - Usually subcutaneous, but in rare cases,
can disseminate to visceral organs
Moves along lymphatic channels
Sporotrichosis is also known as
Rose gardeners disease ( a chronic infection caused by the saprophytic dimorphic fungus sporothrix schenckii
Sporotrichosis is usually
and moves along
- Usually subcutaneous, but in rare cases,
can disseminate to visceral organs
Moves along lymphatic channels
Eumycotic mycetoma subcutaneous
- Pseudallescheria boydii
- Acremonium falciforme
- Madurella mycetomatis
- Curvularia spp.
- Exophiala jeanselmi
Mycetoma is known as
Madura foot
Mycetoma can be where
- Can be anywhere on body, but foot most
common
Mycetoma has what
granules composed of what
- Draining sinus tracts that communicate with the
exterior of the body - Granules composed of aggregates of organism
Psudallescheria boydii
cleistothecium releasing ascospores
Scedosporium apiospermum
Asexual- anamorph for P.boydii
Subcutaneous phaeohyphomycosis
species
- Infection caused by darkly
pigmented fungi
–Exophiala
–Wangiella
–Fonsecaea
–Alternaria
Species of Phaeohyphomycosis
–Exophiala
–Wangiella
–Fonsecaea
–Alternaria
Subcutaneous Phaeohyphomycosis lesion characteristics
luctuant, tender, blue - gray and had no connection to the surface
Microscopic morphology of Wangeilla dermatitidis
showing flask -
shaped to cylindrical phialides without distinctive collarettes.
Cultures grow at 42°C.
Virulence factors of medically important fungi
- Size: small enough to
reach alveoli - Ability to grow at 37o at
neutral pH - Conversion of mycelial
form to yeast (or
spherule) - Possibly, toxin
production, elastases
Systemic mycoses
organisms
- Any organ, esp. lung
– Histoplasma
– Blastomyces
– Coccidioides
– Paracoccidioides brasiliensis
– Sporothrix
– Aspergillis
Histoplama capsulatum is
Inhalation of what
Exposure to
Worldwide
* Inhalation of spores
* Exposure to birds, including chickens and
bats (feces)
Histoplasma capsulatum
Phagocytized by
calcified in
can cause/ blank
- Phagocytized by macrophages
- Calcification in lungs, liver, spleen
- Can cause acute pulmonary disease
- Can reactivate
- Can disseminate: fatal
Laboratory diagnosis of Histoplasma capsulatum
- Depends upon focus of infection
- Culture is the gold standard, but takes
weeks - Antigen tests are fairly accurate (sputum,
urine, blood) - May see yeast within macrophages or
lesions - Yeasts may be acid fast
Blastomyces causes and is where
- Blastomycosis
- Aka Gilchrist’s disease, Chicago disease
- North America, Africa
Blastomyces disease and exposure
- Occupational exposure - outdoors
- Pulmonary disease
- Multi-organ in immunocompromised
Laboratory diagnosis of Blastomyces
- Culture is the gold standard but takes
weeks - Serology not useful due to cross reactivity
and antigen detection is not sensitive
(false positives) - Presumptive ID depends on visualization
of broad-based yeast.
Coccidiodes immitis causes what and is located where
- Cocccidioidomycosis or valley fever
- Southwestern US
Coccidiodes immitis
most what
a few what
usually blank
detected with
can
- Most virulent
- A few arthroconidia
- Usually resolves (6 weeks)
- Immunity
- Detected with cocccidioidin skin test
- Can disseminate
Paracoccidioides brasiliensis causes what
is where
- South American blastomycosis
(paracoccidioidomycosis) - Endemic in central & south America
Paracoccidioides brasiliensis
is what type of infection
infection symptoms
some strains have
Has what type of wheel
- Chronic, progressive
- Some strains have proteases
- Nasal, oropharyngeal lesions, pulmonary
dissemination - Mariner’s wheel in yeast form
Aspergillus fumigatus
What in compromised
Able to persist in
Blank what ball
Allergic what
Has what toxin
–Opportunistic in
compromised
patients=Able to persist in
tissue – especially
lungs
Pulmonary fungus
ball= Growth in lungs with
tissue breakdown (2
elastases)
Allergic
bronchopulmonary
aspergillosis=
Immune response
to inhaled fungi
Aspergillus flavus
has what and is usually what
- A. flavus - aflatoxin
- Other aspergillus usually opportunistic
