1. Mycology Vignettes
2008

2. (1) Lymphocutaneous sporotrichosis Sporothrix schenckii
Scratched hand while working in garden center, infection spreading up arm
Conidiospore formation on tip of slender conidiophores
Dimorphism
Grows faster at 30C
Infection at wound site, lesion spread along draining lymphatics (sporotrichoid pattern)
Dx: anti-Sporothrix Ab, PCR (if available)
Tx: Itraconazole, amphotericin B if severe

3. (2) Tinea Versicolor Malassezia furfur
Nonpainful lesions lack pigmentation, no inflammation
Not leprosy b/c has normal pain sensation
Normal skin flora, obligate lipophilic
Yeast grows in clusters of near-spherical yeasts and some filamentous forms
Dx: Wood’s light (near u.v.) fluoresce green-yellow, KOH stain

4. (3) Itchy Wresting Jock Tinea corporis, Tinea pedis, Erythrasma
Wrestler has ring of inflamed skin on arm, flaking between toes, infection inside thigh
Arm: Tinea corporis Foot: Tinea pedis Thigh: Erythrasma
Tx: Itraconazole or terbinafine
Arm near-spherical microconidia, zoophilic species
Foot somewhat elongate miroconidia, Trichophyton rubrum
Thigh fluoresce coral-red under Wood’s light, probably Corynebac-terium minutissimum

5. (4) Blastomycosis Blastomyces dermatitidis
Vacation in MN
Non-healing lesions on nose, arm, leg for 6 mo
Pulmonary infiltrates
Dx: Ab to “WI-1” or “A antigen”
Bimorphic, near-spherical yeast which have a broad base to the bud
Grows best at 30C
Tx: Amphotericin B, Itraconazole, Fluconazole (if CNS)

6. (5) Coccidioidomycosis Coccidioides immitis/posadasii
20 yo M in hospital with pneumonia, meningitis with skin lesions on face
Infected in the lung from disturbed soil
Dx: nucleic acid probes specific for rRNA sequences
Spherules mature in tissue and are packed with endospores
Mold produces arthro-spores separated by empty cells
Progressive disease are DTH skin test negative and high complement-fixing titers (IgG)

7. (6) Cryptococcosis Cryptococcus neoformans
HIV+ home remodeler
Poor mental status
Lesions on forearm/butt
Infected in the lungs
Dx: Latex test for Cryptococcus capsular carbohydrate
Pigeon droppings (C. gattii associated with eucalyptus trees, Vancouver)
Budding yeast (india ink), brown colonies on bird seed agar
Affects T-cell mediated immunodeficient

8. (7) Erythema nodosum/multiforme Coccidioides immitis
Traveled in AZ, NV, exposed to dust
Develop painful red bumps, warm, tender
No evidence of infection when scraped on KOH mount
Passenger developed rash
Hypersensitivity rxn
Multiple possible causes, location suggests C. immitis
Adult women susceptible
Tx: steroids (for stress-induced hives)

9. (8) Histoplasmosis Histoplasma capsulatum
Recently emigrated bulder with influenza-like illness, lesions on finger/tongue
Pulmonary infiltrates, severe lung disease
Good prognosis: strong DTH, low CF Ab titer
Two spore forms (large rough, small)
Dimorphic, mycelium produces rough macroconidia and microconidia
Blackbird feces and bat guano in soil and attics

10. (9) Aspergillosis/Zygomycosis
18 yo M treated for leukemia deveops pulmonary disease
Likely infected by air, needs neutropenia
Voriconazole is effective for aspergillis, but not zygomycetes
Patient dies
Not contagious
Aspergillis: septate hyphae with 45⁰ branchs, characteristic conidiophores and conidia
Zygomyces: irregular hyphae, few/no septa, mold grows sporangia

11. (10) Candidiasis Candida albicans
25 yo F with rash, soreness of thighs, vagina, mouth
Dx: Yeasts with germ tubes, chlamydospores, pseudohyphae
Associated with diabetes, AIDS, immunosuppression, poorly-fitting dentures
Invasive disease associated with neutropenia

12. (11) Pneumonia, Meningitis, Catheter Inf
(11) Pneumonia, Meningitis, Catheter Inf. Pneumocystis, Cryptococcus, Candida
22 yo F with SOB, confused, difficulty walking, oral thrush, severe pneumonia, nuchal rigidity, IV catheter infection
Tx broad spectrum ATB and fluconazole (should add TMP-SMX)
Probably HIV positive
P. jiroveci are clumps of cysts in alveoli
C. neoformans caused the meningitis, stains with india ink
Candida species caused the catheter infection, pseudohyphae, budding yeast w/o germ tube