Flashcards on Final Exam
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| Types of Fungal Infections (5) |
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| Superficial Mycoses Dermatophyte Infections Subcutaneous Infections Opportunistic Fungal Infections Systemic Mycoses |
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| Superficial Mycoses |
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| Affect only the stratum corneum; do not cause any tissue response or inflammatory reaction; cosmetic disease |
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| Types of Superficial Mycoses (4) |
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| Tinea versicolor (pityriasis versicolor) White piedra Black piedra Tinea nigra |
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| Keratinophilic |
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| hair,nails, skin |
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| Dermatophytoses |
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| Involve restricted region of the host: tinea X causes lesions that enlarge over time with inflammation occurring at growing edge can be systemic disease in immunocompromised |
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| Dermatophytoses in hair shaft |
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| Gray patch ringworm and Black-dot |
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| Gray patch ringworm caused by |
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| Ectothrix or Macrosporum audouinii, M. ferrugineum |
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| Black-dot caused by |
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| Endothrix or Tichophyton tonsurans, T. violaceum |
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| Dermatophytoses of hair follices |
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| Tinea favosa (Trichophyton schoenlenii) |
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| Dermatophytoses of Nail & nail bed |
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| Tinea unguium (onychomycosis) |
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| Tinea unguium (onychomycosis) characteristics |
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| Difficult to treat; long term therapy |
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| Tinea unguium (onychomycosis) caused by |
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| Trichophyton species, Microsporum species, Epidermopphyton floccosum |
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| Dermatophytoses of the skin (ringworm) |
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| Tinea pedis (athlete’s foot) Tinea corporis (body) Tinea manuum (hand) |
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| Dermatophytoses of the skin (ringworm) caused by |
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| Trichophyton species, Microsporum species, E. floccosum |
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| Phaeohyphomycosis |
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| Cutaneous, subcutaneous or systemic mycoses |
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| Phaeohyphomycosis tissue presentation |
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| dark, yeast-like cells, pseudophyphae-like elements or combination |
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| Chromoblastomycosis |
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| Localized cutaneous & subcutaneous |
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| Chromoblastomycosis tissue presentation |
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| rounded sclerotic bodies (copper pennies) |
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| Mycetoma |
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| Chronic infection characterized by swollen tumor-like lesions that yield granular pus through draining sinuses usually on hands and feet, the granules contain masses of mycelia |
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| Systemic Mycoses |
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| Primary infection (respiratory) followed by dissemination to any organ with predisposition to dissemination |
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| Systemic Mycoses caused by |
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| dimorphic species |
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| How to ID Moulds Macroscopically |
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| Growth rate Texture Color |
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| How to ID Moulds Microscopically |
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| Septate vs nonseptate hyphae Hyaline or dematiaceous hyphae Types, size, shape & arrangement of conidia |
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| How to examine moulds microscopically |
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| Prepare in biologic safety cabinet Lactophenol cotton blue (LPCB) Examine at 10X & 40X |
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| Methods for microscopic examination |
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| Tease mounts Cellophane tape preparations Slide cultures |
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| List of the Dimorphic moulds (6) |
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| Blastomyces dermatitidis Coccidioides immitis Histoplasma capsulatum Paracoccidiodes brasiliensis Sporothrix schenckii Penicillium marneffei |
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| List the Dermatophyte fungi |
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| Microsporum, Trichophyton, and Epidermophyton |
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| Black piedra etiologic agent |
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| dematiacious fungus Piedrais hortae |
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| Black piedra disease state |
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| fungal infection of the hair of the scalp |
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| tinea vesicolor etiologic agent |
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| Malassezia globosa |
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| tinea vesicolor disease state |
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| superficial mycoses, affects only stratum corneum, does not cause tissue response or inflammatory reaction, cosmetic disease |
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| sporotrichosis etiologic agent |
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| Sporothrix schenckii |
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| sporotrichosis disease state |
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| rose thorn trauma, chronic nodule and ulcerative lesions along the lymph channels that drain primary site, rarely disseminated |
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| paracoccidioidomycosis etiologic agent |
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| Paracoccidiodes brasiliensis |
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| paracoccidioidomycosis disease state |
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| aka S. American blastomycosis, asymptomatic disease but can disseminate to ulcerative granulomatous lesions of buccal, nasal and GI mucosa |
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| coccidioidomycosis etiologic agent |
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| Coccidioides immitis |
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| coccidioidomycosis disease state |
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| valley fever, primary disease is aymptomatic sometimes has erythema nodosum, erythema multiforme or arthritis, secondary disease is a progressive pulmonary disease, can be single or multisystem and can lead to dissemination |
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| blastomycosis etiologic agent |
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| Blastomyces dermatitidis |
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| blastomycosis disease state |
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| Mississippi, Ohio, and Missouri river valleys, inhale the conidia and causes flu-like symptoms, pulmonary disease and invasive disease of skin, bone and multiple organs |
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| histoplasmosis etiologic agent |
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| Histoplasma capsulatum |
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| histoplasmosis disease state |
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| darlings/spelunker’s disease, in a person with an intact immune system the disease is asymptomatic but heavy exposure can cause acute pulmonary disease, immunocomprimised people have a progressive pulmonary disease to fatal disseminated disease |
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| aspergillosis etiologic agent |
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| aspergillus spp. |
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| aspergillosis disease state |
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| disseminated infection, pulmonary or sinus fungus ball, allergic bronchopulmonary disease, external otomcycosis, mycotic keratitis, onychomycosis, sinutitis, endocarditis, and CNS infections |
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| white piedra etiologic agent |
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| Trichosporon spp. |
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| white piedra disease state |
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| mycosis of the hair, soft nodules composed of yeast cells and arthroconidis that emcompass hair shaft |
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| List the common opportunistic saprobes associated with infections in immuno-compromised hosts. |
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| Aspergillus, Fusarium, Rhizopus and Mucor, dematiacious fungi, yeasts, and zygomycetes |
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| Blastomyces dermatitidis location |
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| Mississippi, Ohio & Missouri River valleys |
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| Direct examination of Blastomyces dermatitidis |
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| thick walled yeast cells 8-15µm with single broad based bud |
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| Blastomyces dermatitidis growth rate |
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| mature within 14 days |
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| Blastomyces dermatitidis colony morphology at 25-30 C (SDA) |
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| 1st yeast-like, then prickly, & finally cottony; white turning tan-brown with age; reverse: tan |
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| Blastomyces dermatitidis colony morphology at 35-37 C (BHI) |
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| cream-tan, heaped or wrinkled & waxy; yeast form inhibited by cyclohexamide |
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| Blastomyces dermatitidis microscopic morphology at 25-30 C (SDA) |
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| septate hyphae with round-pear-shaped conidia attached to conidiophores or directly on hyphae |
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| Blastomyces dermatitidis microscopic morphology at 35-37 C (BHI) |
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| yeast-like cells 8-15 µm, thick walled & appearing double contoured with single broad based buds |
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| Exoantigen of Blastomyces dermatitidis |
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| nucleic acid probe |
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| Coccidioides immitis location |
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| San Joaquin Valley in California, Arizonia, southwest Texas |
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| Direct examination of Coccidioides immitis |
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| non-budding, thick walled spherule, 20-200µm, containing non-budding endospores |
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| Coccidioides immitis growth rate |
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| Moderate, mature 10 days |
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| Coccidioides immitis colony morphology at 25-30 C (SDA) |
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| 1st moist, grayish; soon white cottony; becomes gray-tan-brown with age; reverse white to gray |
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| Coccidioides immitis colony morphology at 35-37 C specilized media |
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| spherule formation |
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| Coccidioides immitis microscopic morphology at 25-30 C (SDA) |
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| septate, branched hyphae that produce thick-walled, barrel-shaped arthroconidia that alternate with empty cells |
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| Coccidioides immitis confirmatory tests |
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| Specific DNA probe Immunodiffusion for exoantigen Demonstration of spherules with special media Demonstration of spherules by animal inoculation |
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| Histoplasma capsulatum location |
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| Worldwide, but highest in Ohio, Missouri & Mississippi River valleys |
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| Direct examination of Histoplasma capsulatum |
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| hard to detect; small yeast in bone marrow |
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| Histoplasma capsulatum growth rate |
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| Slow; 15-20 days to 8 weeks |
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| Histoplasma capsulatum colony morphology at 25-30 C (SDA) |
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| white-brown or pinkish with a dense cottony texture; reverse: white but may be yellow or orange tan |
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| Histoplasma capsulatum colony morphology at 35-37 C (BHI) |
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| moist, white yeast-like colonies; yeast phase is inhibited by cyclohexamide |
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| Histoplasma capsulatum microscopic morphology at 25-30 C (SDA) |
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| young cultures-septate hyphae with pear-shaped smooth or spiny microconidia on short branches or directly on hyphae Older cultures: large thick-walled round to pear-shaped tuberculate macroconidia |
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| Histoplasma capsulatum microscopic morphology at 35-37 C (BHI) |
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| small round or oval budding yeast |
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| Histoplasma capsulatum confirmatory tests |
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| exoantigen, DNA probe |
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| Paracoccidiodes brasiliensis location |
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| Central & South America |
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| Paracoccidiodes brasiliensis Direct Examination |
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| Large, round-oval multiply budding yeast cells |
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| Paracoccidiodes brasiliensis Growth rate |
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| Slow, mature in 21 days |
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| Paracoccidiodes brasiliensis colony morphology at 25-30 C (SDA) |
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| white, heaped, compact, folded, & glabrous or with short white aerial mycelium that turns brown with age |
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| Paracoccidiodes brasiliensis colony morphology at 35-37 C (BHI) |
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| heaped, cream-tan, moist, often becomes waxy |
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| Paracoccidiodes brasiliensis micrscopic morphology at 25-30 C (SDA) |
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| septate, branched hyphae with intercalary & terminal chlamydospores; few microconidia along the hyphae |
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| Paracoccidiodes brasiliensis micrscopic morphology at 35-37 C (BHI) |
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| large, round, thick walled cells with single & multiple buds attached by narrow connections (ship’s wheel) |
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| Paracoccidiodes brasiliensis confirmatory tests |
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| conversion of mold form to yeast phase essential |
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| Sporothrix schenckii location |
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| worldwide |
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| Sporothrix schenckii direct examination |
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| rarely useful; small round-oval-cigar shaped yeast cells |
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| Sporothrix schenckii growth rate |
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| mature in 4 days |
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| Sporothrix schenckii colony morphology 25-30 C (SDA) |
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| 1st small white; later moist, wrinkled, leathery or velvety & often turn brown to black |
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| Sporothrix schenckii colony morphology 35-37 C (BHI) |
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| cream or tan, smooth & yeast-like |
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| Sporothrix schenckii microscopic morphology 25-30 C (SDA) |
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| thin septate & branching hyphae with slender conidiophores that bear many pear-round conidia on delicate denticles (rosettes) |
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| Sporothrix schenckii microscopic morphology 35-37 C (BHI) |
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| round, oval & fusiform budding yeasts of various sizes (cigar bodies) |
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| Sporothrix schenckii confirmatory tests |
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| Conversion of mold to yeast form |
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| Penicillium marneffei location |
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| Southeast Asia; associated with bamboo rat |
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| Penicillium marneffei disease |
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| focal cutaneous or mucocutaneous infection; progressive disseminated disease |
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| Penicillium marneffei direct examination |
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| examination:yeast-like organisms, 2-6µm; no budding; crosswalls or internal septae |
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| Penicillium marneffei growth rate |
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| rapid within 3 days; yeast forms slower; inhibited by cyclohexamide |
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| Penicillium marneffei colony morphology 25-30 C (SDA) |
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| 1st flat, powdery to velvety & tan; later becoming reddish yellow with a yellow or white edge; sometimes a bluish center; soluble reddish pigment observed after 3-7 days; reverse: brownish red |
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| Penicillium marneffei colony morphology 35-37 C (SDA, IMA, BHI) |
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| white-tan, dry, yeast-like; conversion to yeast form enhanced by shaker or blood agar |
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| Penicillium marneffei microscopic morphology 25-30 C (SDA) |
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| septate hyphae; smooth conidiophores with termial verticles of 4-5 metulae; each metula beats 4-6 philades; condia in chains, round to oval |
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| icillium marneffei microscopic morphology 35-37 C (SDA, IMA, BHI) |
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| round-oval yeastlike cells; central crosswalls (fission not budding) |
