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Zygomycetes spp + how do you tell them apart?
- Rhizopus: no branching and HAS rhizoid
- Mucor: branching and NO rhizoid
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Zygomycetes - hyphae, septa, unique structures, habitat, infection, disease
- hyphae: large, ribbon-like
- septa: mostly non-septate
- structures: sporangia (saclike fruiting structures)
- Sporangiospores (spores WITHIN sporangium)
- sporangiophore (supporting structure for sporangium)
- zygosporangium (thick-walled resting spore)
- suspensors (provide structural support for zygospore)
- Rhizoids (root-like structures)
- infection: inhalation
- rarely trauma or ingestion
- disease: immunocomp are at risk (diabetes, prolonged drug therapy)
- Mucormycosis - vascular invasion (rhinocerebral), various invasion and necrosis
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Describe the reproductive cycle of Zygomycetes (image)
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Zygomycetes - appearance on plate
- Fluffy (cotton candy)
- lid lifters (grow faster than other fungi)
- Hyphae are grayish and dotted w/ dark sporangia
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Where do dermatophytes infect and why?
- Dermatophites are restricted to the outer skin
- They utilize keratin as a N source and require a lower temp
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What is dermatomycoses? Tinea? Tinea capitis, tinea barbae, tinea corporis, tinea cruris, tinea pedis, tinea manuum, tinea unguium
- Dermatomycoses: infections of the hair, skin, and nails
- tinea: ringworm
- tinea capitis: scalp (hair loss)
- tinea barbae: chin/beard (mainly from animals)
- tinea corporis: body
- tinea cruris: groin ("jock itch")
- tinea pedis: foot ("athlete's foot")
- tinea manuum: hand
- tinea unguium: nails (persistant colonization)
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Tricophyton general - Conidia, types of invasion, ID
- conidia: numerous microconidia (spherical, teardrop/clublike)
- rare macroconidia (smooth, club-shaped, thin-walled) - peapod esque
- invasion: endothrix (hair shaft filled w/ arthroconidia)
- ectothrix (spores are found around the hair shaft)
- ID: infected hairs do not fluroesce under UV
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Trichophyton rubrum - hair perforation, fast/slow, unique colony, unique micro
- hair: does not perforate
- speed: slow
- colony: cherry-red reverse surface
- cigar shaped 3-8 septa macroconidia
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Trichophyton mentagrophytes- hair perforation, fast/slow, unique colony, unique micro
- hair: perforates
- speed: rapid
- colony: orange-red reverse
- conidia: round grape-like cluser microconidia
- cigar shaped 2-5 septa macroconidia
- coiled spiral hyphae
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Trichophyton tonsurans- fast/slow, unique colony, unique micro, requirements, disease
- speed: slow
- colony: brown, wrinkled, suedelike w/ deep fissures
- micro: "birds on a wire" microconidia
- req: needs enriched media (BHA, SDA)
- disease: epidemic form of tinea capitis (mainly children)
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Microsporum audouinii - disease, ID, unique colony, unique micro
- disease: tinea capitis among schoolchildren (spread by infected hair)
- ID: infected hair shafts fluroesce yellow-green
- salmon-pink
- micro: Antler and racquet hyphae
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Microsporum canis - disease, ID, unique colony, unique micro
- disease: ringworm in dogs/cats (and humans who come in contact with them)
- ID: infected hair shafts fluoresce yellow-green
- colony: fluffy white/buff w/ yellow fringe
- bright yellow-orange reverse
- micro: microconidia varies, but macroconidia are plentiful
- macroconidia are large 'spindle-shaped' (pea pod) w/ spiny projections
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Epidermophyton floccosum - disease, unique colony, unique micro
- disease: infection in skin and nails (not hair)
- colony: yellow/khaki w/ orange/brown reverse
- lumpy and sparse, radially grooved
- micro: no microconidia
- numerous club-shaped macroconidia that transform into chlamydoconidia
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Aspergillis general - type of infections, classification
- infections: opportunistic mycoses
- disseminated infections, sinus fungus ball, otomycosis, onychomycosis
- class: either Ascomycota OR Deuteromycota (fungi imperfecti)
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Aspergillus fumigatus - unique colony, unique micro
- colony: fluffly, white to blue-green
- micro: branching of hyphae, conidiophores w/ a foot cell at base (macroscopic)
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Aspergillus niger - unique colony, unique micro
- colony: yellow colonies that turn black, appear "peppery"
- micro: darkly pigmented spores (macroscopic)
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Penicillium general - unique colony, unique micro
- colony: green to blue-green colonies w/ velvety surface
- micro: brushlike conidiophores
- hyaline (clear) septate hyphae
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Fusarium general - disease, unique colony, unique micro
- disease: necrotic skin lesions, wound infection
- colony: cottony, fluffy w/ varying colors (pink shown)
- micro: canoe shaped macroconidia
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What causes most systemic mycoses? How are most detected?
- Dimoprhic fungi (yeast and mold form)
- Immunocmp at greater risk
- most detected via serological testing or biopsy
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Blastomyces dermatitidis - disease, habitat, transmission, specimen, unique colony, unique micro
- disease: blastomycosis
- starts in lungs and disseminates
- acute or chronic suppurative and granulomatous infections anywhere in body
- habitat: central and southeastern US
- transmission: airborne spores from contam soil
- specimen: bronchial, blood
- colony: 25C on SDA = yeast like then prickly, then cottony
- 37C on BHI = large, thick-walled, round yeasts
- micro: 25C on SDA = round conidia on apex of conidiophore (lollipop like)
- 37C on BHI = yeast-like cells that bud on broad base
- *definitive ID through culture conversion, Ag testing, or PCR
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Coccoides immitis - unique, disease, habitat, transmission, considerations, unique colony, unique micro
- unique: dimporphism not dependent on temperature
- spherule NOT yeast
- disease: valley fever (coccidiomycosis)
- self-limiting lung infections
- severe infections (chronic pneumonia) require treatment
- MAY DISSEMINATE
- habitat: endemic in dry desert-like areas (CA)
- transmission: inhalation of arthrospores from infected soil, dust
- considerations: easily transmissible (BSC, no slide cultures, etc)
- "selected agent"
= many steps to transport - colony: moist, white, "ice-rink" to cottony w/ age
- *can induce spherule formation
- micro: thick-walled barrel-shaped arthroconidia that alernate w/ empty cells
- Spherule phase are circular and contain endospores (multiple stains appear differently)
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Histoplasma capsulatum - disease, habitat, transmission, specimen, unique colony, unique micro
- disease: histoplasmosis
- chronic, granulomatous infection of reticuloendothelial system (can be fatal)
- habitat: meidwest and SE US
- transmission: inhalation of aerosolized conidia
- associated with birds (chicken houses) and bats (caver's disease)
- specimen: respiratory, bone marrow
- colony: 25C = fine and dense white-brown
- 37C = yeast-like colonies (inhibit by cyclohexamide)
- micro: 25C = tuberculate macroconidia (diagnostic)
- 37C = small round oval-budding cells
- *thermal conversion not always achieveable
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Sporothrix schenckii - disease, transmission, specimen, unique colony, unique micro
- disease: Rose gardener's disease (sporotrichosis)
- minor skin wound -> lymphatic -> subcutaneous infection (rarely leaves lymph system)
- Pulmonary disease if inhaled
- transmission: trauma (thorns)
- specimen: aspirate from subcutaneous nodules
- colony: small white w/ no aerial hyphae -> moist wrinkled leathery
- 37C -> yeast round oval budding cells (require several generations for good morph)
- micro: microconidia as flowerets attached to conidiophore by denticle
- 37C -> single or multiple spherical to cigar-shaped yeast cells
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Paracoccidioides brasiliensis - disease, unique colony, unique micro
- disease: South American blastomycosis
- chronic granulomatous disease
- lungs -> mucous membranes nose/mouth -> skin, lymph nodes, organs
- colony: 25C = white folded compact colony
- 37C = heaped, cream-tan, moist/soft
- micro: 25-30C= only septate hyphae, some terminal chlamydospores
- 35-37C = large round thick-walled cells
- buddings attached by narrow connections
- mariner's wheel
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Penicillium mameffei - disease, unique colony, unique micro
- disease: emerging pathogen (mostly immunocomp)
- occasionally SE Asian travelers or indiginous
- colony: 25C SDA = white w/ yellow conidial head that produce a diffusible wine red pigment
- 37C = rough, glabrous, tan-colored, yeast-like
- *conversion best in BHI broth on shaker
- micro: 25C = general Penicillium
- 37C = single celled oval arthroconidia
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