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Mycology Flashcards

1
Q

Lactophenol Cotton Blue Wet Mount

A
  • Most widely used method of staining and observing fungi
  • Lactic acid and Glycerol preserves structures
  • Slides can be made permanent
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2
Q

ASPERGILLUS FUMIGATUS

A
  • Starts with white growth becoming blue-green and eventually grayish-green with age.
  • Columnar symmetry
  • Uniserate phialides cover only 2/3 of the vesicle
  • Thermophilic. Grows well at 45°C, sometimes higher.
  • Causative agent of “Fungus Ball” or Aspergilloma and a type of pulmonary infection termed “Farmer’s Lung.”
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3
Q

ASPERGILLUS NIGER

A
  • Very large compared to many of the other Aspergillus sp.
  • Dark brown/ Black in color.
  • Biserate - Metulae and Phialides present.
  • Radiate Symmetry - arrangement of the metulae and phialides covers the entire vesicle.
  • Colonial appearance often begins as white, turning yellow and becoming black with age.
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4
Q

ASPERGILLUS CLAVATUS

A
  • Huge club-shaped vesicle (~ 200 x 40 um)
  • Phialides are same size as those of other Aspergillus species, appears so small due to enormous size of vesicle
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5
Q

ASPERGILLUS NIDULANS

A
  • Typically smaller than most of the other Aspergillus sp. Due to its short conidiophore.
  • Colonial Morphology is Dark green/olive buff with a purple or olive reverse.
  • Columnar symmetry, biserate with a pale brown conidiophore.
  • Round hülle cells produced
  • Cleistothecia with RED ascospores
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6
Q

ASPERGILLUS FLAVUS

A
  • Common food-borne fungus
  • Many strains produce aflatoxins
  • Colony: yellowish-green (lime color) surface
  • Microscopic: rough, spiny neck develops with age
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7
Q

ASPERGILLUS TERREUS

A

Macroscopic: Cinnamon brown color

Microscopic: Columnar fruiting structure

Biseriate phialides

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8
Q

ASPERGILLUS VERSICOLOR

A

Macroscopic: Colony mostly green or tan with spots of various colors

Microscopic: Biseriate phialides, loosely radiate, cover most of vesicle

Small conidial head resembling Penicillium

Hülle cells produced

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9
Q

ASPERGILLUS GLAUCUS GROUP

A
  • Macroscopic: Colony mostly green or tan with spots of various colors
  • Microscopic: uniseriate phialides,
  • Cleistothecia on sexual state (Eurotium herbariorum) release ascospores
  • Grows best with 20% sucrose added to medium
  • Seldom encountered clinically
  • Worldwide in nature; prefers dry environment
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10
Q

CANDIDA ALBICANS

A
  • SAB DEX = Cream-colored, pasty, smooth
  • CHOM AGAR = Green
  • Microscopic Morphology
    • SAB DEX
      • Round to oval cells
    • Cornmeal tween 80/ DALMAU PLATE
      • Formation of pseudohyphae
      • clusters of blastoconidia
      • formation of clamydoconidia
      • 25 degrees
    • Positive germ tube
    • growth at 42 degrees
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11
Q

CANDIDA DUBLINIENSIS

A
  • Pathogenicity
    • oral candidiasis
    • immunocompromised
    • Fluconazole Resistantnce
  • Growth rate
    • 3 days
  • Colony Morphology
    • Sab Dex
      • Cream colored, pasty, smooth
    • Chrom agar
      • Green
  • Microscopic Morphology
    • Sab Dex
      • Round to oval cells
    • Cornmeal tween 80/Dalmau Plate
      • formation of pseudohyphae or hyphae
      • clusters of blastocondia
      • formation of chlamydoconidia/chlamydospores(pairs or clusters)
    • Positive Germ tube test
    • No growth at 42 degrees
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12
Q

CANDIDA GLABRATA (tropulopsis glabrata)

A
  • Pathogenicity
    • Bloodstream
    • UTI
    • Reduced fluconazole Susc.
    • found in healthy individuals
  • Growth rate
    • 3-5 days
    • Cholesterol may enhance or depend on
  • Colony Morphology
    • Sab Dex
      • Small, partly smooth
      • White to cream-colored
    • Chromagar
      • Pink with darker center
      • Smooth
  • Microscopic Morphology
    • Sab Dex
      • oval cells
    • Cornmeal Tween 80
      • Small oval cells
      • single terminal budding
      • no Pseudohyphae
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13
Q

CANDIDA KEFYR (Pseudotropicalis)

A
  • Pathogenicity
    • Infections in susceptible individuals
  • Growth rate
    • 3 days
  • Colony Morphology
    • Sab Dex
      • Smooth
      • White to cream-colored
    • Chromagar
      • Pink to Lavender
  • Microscopic Morphology
    • Sab Dex
      • Round to oval cells
    • Cornmeal Tween 80
      • pseudohyphae with elongated blastoconidia that line up in parallel (logs in a stream)
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14
Q

CANDIDA KRUSEI

A
  • Pathogenicity
    • susceptible individuals 2%
    • Resistant to fluconazole
  • Growth rate
    • 3 days
  • Colony Morphology
    • Sab Dex
      • cream colored, flat, dull, dry
      • develop mycelial edge
    • Chrom Agar
      • Rough
      • Pink centered and white border
  • Microscopic Morphology
    • Sab Dex
      • Round oval or elongated cells
    • Cornmeal Tween 80
      • Pseudohyphae with elongate blastoconidia (matchsticks or trees)
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15
Q

CANDIDA PARAPSILOSIS GROUP

A
  • Pathogenicity
    • infections in susceptible individuals 6%
    • 2nd most common agent of fungal endocarditis
    • Responsible for invasive infections in neonates
  • Growth rate
    • 3 days
  • Colony Morphology
    • Sab Dex
      • Creamy, sometimes lacy appearance
    • Chrom Agar
      • White to pink
  • Microscopic Morphology
    • Sab Dex
      • Ovoid Cells
    • Cornmeal Tween 80
      • Blastoconidia(single or small clusters) along pseudohyphae
      • Pseudohyphae appear curved
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16
Q

CANDIDA TROPICALIS

A
  • Pathogenicity
    • Known to cause infection in immunocomprimised patients 7%
    • Virulent in combination with leukemia
    • Found in patients without evidence of disease
  • Growth rate
    • 3 days
  • Colony Morphology
    • Sab Dex
      • Creamy, may be wrinkled
    • Chrom Agar
      • Blue
  • Microscopic Morphology
    • Sab Dex
      • Round to oval cells
    • Cornmeal tween 80
      • Forms blastoconidia singly or in groups along pseudohyphae
      • True hyphae may be present
      • Few teardrop chlamydospores rarely produced
    • Negative germ test
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17
Q

GEOTRICHUM CANDIDUM

A
  • Pathogenicity
    • role is uncertain
    • normal flora
    • pulmonary disease in immunocompromised
  • Growth rate
    • 4 days
  • Colony Morphology
    • 25 degrees
      • early stages
        • white, moist
        • easily picked off media
      • later stages
        • submerged hyphae (ground glass)
        • may develop short, white colony ariel mycelium
    • 37 degrees
      • most strains will not grow
      • some strains will have minimal surface growth and extensive subsurface growth
  • Microscopic Morphology
    • Course true hyphae ( No Pseudo)
    • rectangular arthroconidia that germinate from one corner
      • may become rounded
    • no blastoconidia
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18
Q

MALASSEZIA SPECIES

A
  • Pathogenicity
    • part of normal skin flora
    • M. globosa, M. Sympodhalis
    • agents of pityriasis (tinea) Versicolor, folliculitis, seborrheic dermatitis, catheter-associated sepsis
  • Growth rate
    • 5 days 30-35 degrees
    • poor growth at 25 degrees
    • growth requirements
      • Cycloheximide
      • Long-chain fatty acids (Olive oil)
  • Colony Morphology
    • Smooth, cream to yellowish brown
    • often becomes dry, dull, brittle and wrinkled with age
  • Microscopic Morphology
    • yeast-like cells are phialides with collarettes
    • cells are round at one end and blunt at another
      • budlike structures form single at blunt end
    • Hyphae are usually bent
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19
Q

TRICHOSPORON SPECIES

A
  • Pathogenicity
    • causes invasive localized and disseminated disease
    • immunocompromised neutropenic patients susceptible
    • Some species cause white piedra
    • Normal flora of skin, nail, and mouth
  • Growth rate
    • 5 -7 days
  • Colony Morphology
    • At first,
      • cream-colored, moist, and soft
    • With age, wrinkled and powdery or crum-like
      • heaped center
      • adherence to cracking of agar
      • yellow-grey coloring
  • Microscopic Morphology
    • cornmeal tween agar
    • true and pseudohyphae formation
    • blastoconidia single or in chains
    • arthroconidia on older cultures
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20
Q

Cryptococcus neoformans Clinical Significance

A
  • Route of Infection
    • AEROSOLIZATION
    • INHALATION
  • VIRULENCE FACTORS
    • Polysaccharide Capsule
    • Ability to grow at 37 C
    • Phospholipase Enzymes
    • Phenoloxidase Enzymes
    • in dry environments,
    • yeast is
    • small enough to be inhaled into
    • alveolar space
  • Fungus can cause acute lung infection or no
  • symptoms at all
  • Reactivation in immunosuppressed persons
  • (HIV/AIDS, especially CD4 <100)
  • Meningitis is the most common presentation
  • Cryptococcal infection
  • CRYPTOCOCCOSIS
  • Primary pulmonary infection in immunocompetent persons,
  • commonly presents with fever and dry cough.
  • Immunocompromised patients:
  • Meningitis:headache,neck pain,fever, visual disturbance,confusion.
  • Disseminated infection - kidneys, prostate, bone, and skin
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21
Q

Cryptococcus neoformans ID

A
  • Direct Examination/India Ink
  • Culture and Identification
  • Cytology and Histopathology
  • Serology
  • Moist colonial morphology,
    • appears “runny”
    • Very round yeast-like cells, with a narrow “Isthmus” between
    • mother and daughter cell, almost an invisible attachment.
  • Inositol Assimilation positive
  • Urease positive
  • Polysaccharide Capsules can be seen with India Ink.
  • Melanin pigment is produced on “Birdseed”, “Caffeic Acid”,
  • “Staib” or “Niger seed” Agars
  • C. neoformans does NOT grow in the presence of Cyclohexamide.
  • Specimen
    • CSF
    • Respiratory
    • Tissue
    • Blood
  • Medias
    • 10% KOH
    • Calcofluor
    • Gram’s Stain
    • India Ink
    • Histological
    • H&E
    • Mucicarmine
    • PRIMARY ISOLATION
      • SABOURAUD DEXTROSE
      • INHIBITORY MOLD
      • BHI
    • ISOLATION FROM CULTURE
      • DIFFERENTIAL MEDIA
      • BIRD SEED AGAR
      • CAFFEIC ACID AGAR
      • GROWTH OF DARK
      • BROWN TO BLACK
      • COLONIES IN 2-5 DAYS
  • Microscopic Morphology
    • round, narrow budding yeasts with size variation
    • no true hyphae
    • pseudohyphae absent or rudimentary
    • capsule
  • Macroscopic Morphology
    • soft, glistening to dull, smooth colony, usually mucoid
    • cream, slightly pink, or yellowish-brown color
    • growth at 25oC and 37oC
  • NOTE: THIS CHARACTERISTIC SEPARATES C. NEOFORMANS FROM OTHER CRYPTOCOCCUS
  • SPECIES, HOWEVER, SOME MUTANT STRAINS MAY NOT GROW AT 37oC
    • Cryptococcus neoformans
    • Germ tube (-)
    • On Corn Meal-Tween 80
    • Pseudohyphae (-)
    • Chlamydoconidia (-)
    • Large, round blastoconidia, often well-spaced because of
    • the mucoid capsules (Looks like “frog eggs”)
  • Antigen Detection
    • Complement Fixation
    • Latex Particle Agglutination
    • Antibody Detection
    • IFA, TA
    • Enzyme immunoassay (EIA)
    • Lateral flow assay (LFA)
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22
Q

Cryptococcus gattii VS. C. neoformans

A
  • Spherical yeast
  • Has prominent polysaccharide capsule
  • Replicates by budding
  • Causes respiratory and CNS infections in humans and animals
  • Positive for urea hydrolysis
  • Negative for growth on cycloheximide containing media
  • Produces phenol oxidase (brown on birdseed agar)
  • C. gattii
    • Nonimmunocompromised
    • Associated with tree bark
    • Causes large lesions in the lung
    • &/or brain (
    • Assimilates glycine; grows in
    • the presence of L Canavanine
  • C. neoformans
    • Immunocompromised
    • Associated with pigeons
    • Does not usually cause
    • Cryptococcomas
    • No glycine assimilation; does
    • not grow in the presence of
    • L canavanine
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23
Q

CHROMOBLASTOMYCOSIS

A
  • Chronic disease of skin and subcutaneous tissue and is caused by a group of melanoid fungi
  • In tissue, the fungal elements manifest as non budding, thick walled, pigmented, muriform cells
  • Formation of verrucoid (rough), warty, cutaneous nodules, which may be
  • raised 1 3 cm above the skin surface
  • soil inhabiting fungi : enters hand or feet after trauma
  • found primarily in the tropics or subtropics
  • dull red or violet color on skin may resemble a ringworm lesion
  • pruritus (itchiness) and papules may develop
  • fungus gets under the skin (produces bumps)
  • may spread to brain (life threatening in that case)
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24
Q

Chromoblastomycosis ID

A
  • Etiologic Agents
    • Cladophialophora carrionii
    • Phialophora verrucosa
    • Rhinocladiella aquaspersa
    • Fonsecaea compacta
    • Fonsecaea pedrosoi
  • Culture:
    • Sabouraud’s dextrose agar.
    • Interpretation: clinical history and direct microscopic evidence are considered significant.
    • Culture identification is the only reliable means of distinguishing these fungi.
    • Identification:
      • Culture characteristics and microscopic morphology especially conidial
      • morphology, the arrangement of conidia on the conidiogenous cell and the
      • morphology of the conidiogenous cell.
        *
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25
Q

Cladophialophora carrionii

26
Q

Phialophora verrucosa

A
  • an agent of chromoblastomycosis phaeohypomycosis
  • other reported infections include endocarditis, keratitis, and osteomyelitis
  • Pigmented septate hyphae
  • Vase shaped phialides with flared, darker collarettes
  • Clusters of conidia
27
Q

Rhinocladiella aquaspersa

A
  • Sympodial conidia
  • Conidiophores straight, upright, unbranched, thick walled, and dark brown.
28
Q

Fonsecaea compacta and Fonsecaea pedrosoi

A
  • Fonsecaea pedrosoi
  • Fonsecaea compacta
  • dematiaceous (dark/brown) septate and loosely branching hyphae.
  • conidia produced are pale brown or olivaceous in color
  • In tissues, it appears as large (5 12 µm diameter), round, brownish
  • and thick-walled bodies
  • Can exhibit different morphotypes
    • Cladosporium type
    • Phialophora type
    • Rhinocladiella type
  • Conidiophores are long, septate
  • Conidia produced from tips of condiophores but also along condiophore
  • sides and directly from hyphae
29
Q

Four types of superficial infections

A
  • Tinea/Pityriasis versicolor (Malassezia sp.)
  • Tinea nigra (Hortaea werneckii)
  • Black piedra (Piedraia hortae)
  • White piedra (Trichosporon sp.)
30
Q

Malassezia furfur

A
  • Tinea/Pityriasis versicolor
  • M. furfur is a lipophilic yeast and normal skin flora
  • May cause systemic infections in patients receiving prolonged infusions of lipids through central catheters
  • Direct examination of skin scraping in 10% KOH prep
    Round to oval cells in clusters, accompanied by short, angular hyphae (spaghetti and meatball)
  • Isolation and Culture M. furfur grows poorly on regular
  • SAB
  • Produce pinpoint colonies at first
  • Grows well when overlaid with olive
  • oil (lipophilic)
31
Q 
Hortaea werneckii (Phaeoannelomyces werneckii and
Exophiala werneckii)
A
  • Superficial infection of the skin
  • Primarily found in tropical regions of Central and
  • South America and the Caribbean, and occasionally in humid regions of the US
  • Causes dark brown/black patches on skin of palms and sometimes the soles of the feet
  • Direct Microscopic Exam of Hortaea werneckii
  • Skin scraping in 10% KOH and Parker ink or calcoflour white mounts
  • Isolation and Culture of Hortaea werneckii
  • Colonies are slow growing (3 weeks), shiny, olive to greenish black yeast-like colonies
  • Two-celled cylindrical yeast-like cells that after 7 days colonies may develop a dark
  • septate hyphae with annellation.
32
Q

Piedraia hortae

A
  • Formation of hard black nodules on the
  • shafts of the scalp, beard, mustache and groin
  • Primarily in tropics – Central & South
  • America, SE Asia & Africa
  • Direct Microscopic Exam
  • Hairs containing one or more black nodules are placed in 10-25% KOH, shows compact
  • masses of dark, septate hyphae and round to oval asci containing ascospores
  • Isolation and Culture
    • Hair fragments implanted onto primary
    • isolation media (SAB Dex agar)
    • Colonies of Piedraia hortae are dark greenish,
    • brown to black, glabrous or covered with very short aerial hyphae
    • Closely septate hyphae, dark and thick walled, intercalary cells
33
Q

Trichosporon asahi

A
  • White Piedra
  • Fungal infection of hair shaft characterized by the presence of soft white, yellowish, beige or green nodules on hair shafts of face, axilla or genital area
  • More common in South America, Africa and Asia
  • Trichosporon ovoides- scalp hair white piedra
  • Trichosporon inkin - most cases of pubic white piedra
  • Characterized by irregular, soft, white to light brown nodules
  • Direct Microscopic Exam
    • Hair should be examined using 10% or 25%
    • KOH or calcoflour white
    • Look for irregular, soft, white or light brown
    • nodules firmly adhering to the hairs
  • Isolation and Culture
    • Grows on SGA with antibiotics without cycloheximide, since this drug is inhibitory to some of the species
    • Grows rapidly, white or yellowish to deep cream colored, smooth, wrinkled, velvety with a mycelial fringe
    • Microscopic: True hyphae and pseudohyphae
    • with blastoconidia singly or in short chains
34
Q

Mycetoma Clinical Significance

A
  • Cutaneous infection from introduction of pathogen from trauma often in the feet or hands
  • Sulfur granules from draining sinuses
  • inflammation and black tissue
  • India from farm workers
35
Q

Scedosporium complex (asexual) and Psuedaellescheria boydii (sexual)

A
  • Scedosporium Complex
    • annelloconidia
    • “Lolipop” like appearance
    • single stalk with conidia at the tip or base
  • Psuedaellescheria boydii
    • Cat-Fur like colony
    • Cleistothecia
36
Q

Pneumocystis jirovecii Clinical Significance

A
  • Pneumonia with cysts
  • Pneumatocysts
  • Cannot be cultured
  • Diagnosis of cysts
37
Q

Blastomycosis

A
  • chronic granulomatous and suppurative disease having a primary pulmonary stage
    • frequently followed by dissemination to other body sites chiefly, the bone and skin
  • Synonymns
    • Gilchrist’s Disease
    • Chicago Disease
    • North American Blastomycosis
  • Blastomyces dermatitidis
  • Endemic Worldwide
    • Most cases are seen in North America-North American Blastomycosis.
    • Not Cali
  • Not subclinical- Not opportunistic
  • Manifestations
    • Primary pulmonary (–> acute pulm.)
    • Chronic cutaneous
    • Extrapulmonary
    • Systemic
  • Dimorphic
38
Q

Blastomyces dermatitidis ID

A
  • one-celled, smooth-walled conidia borne on short lateral to terminal hyphal branches
  • Diagnosis
    • Direct Exam
      • See characteristic yeast form in tissues
    • Fungal culture
      • recovery of dimorphic fungus Blastomyces dermatitidis
    • Exoantigen test
    • DNA probe
  • Cycloheximide in selective fungal media inhibits the yeast form of Blastomyces dermatitidis
  • Definitive ID
    • Conversion from mold phase to the yeast phase
      • subculture mold form to a blood agar plate and incubate at 37 C –look for characteristic yeast forms (2-4 weeks !!!)
39
Q

Coccidioidomycosis Clinical Significance

A
  • Valley Fever or cocci
  • Infection resulting from a soil-dwelling fungus (Coccidioides spp.)
    • C. immitis, C. posadasii
  • Disturbed arthroconidia become airborne and inhaled
    • Infects lungs
    • Incubation period: 1-3 weeks
  • Not transmitted from person-to-person
  • Epicenter: San Joaquin valley
  • Fungus grows in soil in summer and is dispersed in air in late summer and fall
  • Southwestern U.S.
  • Sample Types
    • Sputum (early morning)
    • Tissue Specimens (skin, lung biopsy, bone)
    • Body Fluids (blood, urine)
    • Conidia are highly infectious
    • Slants are preferred to plates
  • Inhaled arthroconidia germinate, produce sporangia
    • “Spherules”, divide internally into “endospores”
  • Acute Pulmonary
    • Malaise
    • Cough
    • Chest pain
    • Fever
    • Arthralgia
    • Weight loss
    • Night sweats
    • Anorexia
40
Q

Coccidioides immitis ID

A
  • Dimorphic
    • Causing systemic mycoses
  • Possess two phases
    • 25° C
      • Filamentous
    • 37° C
      • Budding yeast form or spherules
  • Direct microscopy
    • Wet preparation of fresh clinical specimens
    • Preparations of fixed specimens
  • Isolation and characterization
    • Primary isolation
      • Growth is moderately rapid
      • Texture is wooly to glabrous
      • Surface Color is white but can be beige, pink, yellow or brown
      • Reverse color is pale to dark brown
  • Hyaline, septate hyphae
  • Conidiophores are absent
  • Arthroconidia are barrel shaped alternating with empty cells called disjunctors
  • In infected tissue, spherules containing endospores 10-80um
  • Microscopic morphology:
    • Barrel-shaped arthroconidia
  • Exoantigen test:
    • “F” antigen, “HS” antigen
  • Nucleic Acid probe:
    • Ribosomal RNA:DNA hybrid
    • “Accuprobe”, Gen-probe
  • Direct Smear
    • Sputum, CSF sediment
      • KOH + Calcofluor – spherules w/endospores
    • Biopsy, stain with H&E, PAS, GMS
  • Rapid growth at 25C on Sabouraud medium
    • SCC (Sab + cycloheximide + chloramphenicol)
    • Buff, fluffy, yellow, tan
    • Many airborne arthroconidia.
  • At 25° C and 37° C Growth
  • Moderately rapid
  • Texture
  • Woolly to glabrous
  • Color
  • Surface
    • White, beige, pink, cinnamon, yellow or brown
  • Reverse
    • Pale, orange, or pale to dark brown
41
Q

Histoplasmas Clinical Significance

A
  • Histoplasmosis is an infectious disease caused by inhalation of spores produced by Histoplasma capsulatum
  • Endemic areas
    • Central and eastern United States, around the Ohio and Mississippi River Valleys, as well as parts of Central and South America, Africa, Asia, and Australia.
  • Infectious particles-
    • microconidia, inhaled in dusts of contaminated soil.
    • Converts to yeast form in lungs
  • Influenza-like: fever, cough,
    headache, myalgias
    • Acute or chronic pneumonia
    • Extrapulmonary dissemination in
    immunosuppressed patients (
    I.e. AIDS)
  • *
42
Q

*Histoplasma capsulatum var.
capsulatum ID*

A
  • Microscopic morphology:
    • “ tuberculate” macroconidia
  • Exoantigen test:
    • “h” antigen, “m” antigen
  • Nucleic Acid probe:
    • Ribosomal RNA:DNA hybrid “Accuprobe”, Gen-probe
  • Culture: can be performed on tissue, blood, and other body fluids, but may take up to 6 weeks to become positive; most useful in the diagnosis of the severe forms of histoplasmosis. A commercially available DNA probe (AccuProbe, GenProbe Inc.) can be used to confirm.
  • Microscopy: for detection of budding yeast in tissue or body fluids, low sensitivity, but can provide a quick proven diagnosis if positive.
  • Direct Smear
    • Sputum
    • Wright’s stain, Gomori metheamine silver (GMS)
    • Biopsy, stained with H&E, PAS,
  • Culture
    • Slow growth at 25C on Sabouraud medium
    • –SCC (Sab + cycloheximide + chloramphenicol)
    • Buff, fluffy, yellow, tan
  • Tuburculate Macroconidia
43
Q

Sporotrichosis Clinical Significance

A
  • Causative agent = Sporothrix schenckii
  • characterized by nodular lesions of the cutaneous or subcutaneous tissues and adjacent lymphatics that suppurate, ulcerate and drain
  • Gardeners’ disease –infection often occurs after thorn prick while gardening
  • The organism is ubiquitous in soil
  • The infection often follows a traumatic injury in which the wound is highly contaminated with soil
  • Pulmonary– inhaling the infectious conidia found in soil
  • Lymphocutaneous (most common)
  • Mucocutaneous (rare) following dissemination
  • Extracutaneous and Disseminated (rare)
    • bone, joint, eye, sinuses, CNS, systemic (multi-organ involvement)
44
Q

Sporothrix schenckii

A
  • Thermally dimorphic fungus
  • Mold form (at 25 C)
  • Macroscopic –light colored (“dirty white”), moist, glaborous and yeast-like at first becoming fuzzier and darker (dark gray-brown mycelium)
  • Microscopic
  • Hyaline septate hyphae with rosettes and birds-on-a-wire conida
  • Yeast form (at 37 C)
    characteristic “cigar-shaped” yeasts
45
Q

Paracoccidioidomycosis Clinical Significance

A
  • Paracoccidiodes brasiliensis
  • Paracoccidioidomycosis is a chronic granulomatous disease that begins as an inapparant pulmonary disease which disseminates to mucocutaneous or mucosal sites
  • Endemic to humid, mountain forests of South America – “South American Blastomycosis”
  • Associated with soil in “coffee-growing regions” (Not endemic to rain forest regions)
  • Primary pulmonary – often subclinical
  • Progressive pulmonary – TB-like
  • Disseminated disease
  • – mucocutaneous (most common)
  • – extracutaneous w/ single organ involvement
  • (rare) (adrenal gland most common – Addisons disease)
  • Generalized disease (rare) – many organs involved
  • Mucocutaneous (mostcommon)
  • Results from dissemination from the primary pulmonary infection
  • granulmonatous disease of buccal, nasal and less commonly GI mucosa
  • Regional lymph nodes are often involved and may form sinus tracts to the skinsurface
46
Q

Paracoccidiodes brasiliensis

A
  • Thermally dimorphic fungus
  • Direct Exam
  • Fungal Culture
  • Direct Exam of clinical material
    • Sputum
    • Biopsy material
    • lymph node drainage
  • Look for characteristic yeast having multiple buds resembling a “mariners wheel”
  • use selective fungal media with
    • chloramphenicol and cycloheximide
  • P. brasiliensis grows very slowly
    • (15 - 25 days @ 25 oC)
47
Q

Phaeohyphomycosis

A
  • traumatic implantation of dark fungi into subcutaneous tissue
  • SUPERFICIAL INFECTIONS:
    • Exophiala spp., Phialophora spp.
  • SYSTEMIC: brain abscess, severe disseminated infection
  • Pulmonary: lung mass
    • Cladophialophora bantiana (brain)
    • Cladosporium
    • Exophiala dermatitidis
    • Exophiala jeanselmei
    • Exophiala spinifera
    • *Phialophora verrucosa
    • Exserohilum spp.
    • Rhinocladiella* mackenziei
    • *Fonsacaea
    • Alternaria alternata
    • Bipolaris australiensis
    • Curvularia lunata
    • Chaetomium, Phoma
48
Q

Black Molds Dematiaceous fungi

A
  • Black colonies
  • Brown hyphae and spores
  • Numerous species
  • Difficult to identify
  • All have one of four types of sporulation
    • Rhinocladiella-like
    • Cladosporium-like
    • Phialophora-like
    • Acrotheca-like
49
Q

Cladophialophora bantiana

A
  • Major cause of cerebral phaeohyphomycosis all over the world
  • Thermotolerant - Grows well at 42-45°C
  • Produces long, branching acropetal chains of blastic conidia with truncate and pointed ends
  • Connecting dark hila between cells inconspicuous
  • Cactus Like Conidia
50
Q

Exophiala jeanselmei

A
  • etiologic agent of eumycetoma, phaeohyphomycosis, and rarely chromoblastomycosis
  • Early growth mucoid, yeast-like (anamorph: Phaeoannellomyces)
  • Becoming velvety, olive-grey to black, producing annellated conidiogenous cells (anamorph: Exophiala)
51
Q

Exophiala dermatitidis

A
  • old name Wangiella dermatitidis
  • agent of cutaneous, deep-seated infection
  • may be found as a colonizer in the lungs of cystic fibrosis patients
  • MACRO: Black, moist, shiny, yeast-like.
  • 2-3 weeks, olive-grey & velvety
  • Microscopic:
  • Abundant, budding yeast-like cells; few brown septate hyphae with ellipsoidal conidia accumulating in groups
  • Apical phialides without a collarette produced from hyphae or on short branches; annellated pores or pegs on the sides of hyphae
52
Q

Aureobasidium pullulans

A
  • mucoid to glabrous, white to black colony
  • Yeast-like conidia (generally non-pigmented) arising in groups laterally from submerged hyphae
  • Older hyphal cells become dark melanoid
  • Rare cause of infection in immunocompromised host
53
Q

Phialophora verrucosa

54
Q

Alternaria alternata

A
  • agent of cutaneous, deep-seated infection
  • Muriform conidia in simple or branching acropetal (youngest at tip) chains
55
Q

Bipolaris australiensis

A
  • Species of Bipolaris are agents of sinusitis and rarely deep-seated infections
  • Holoblastic conidia, darkly pigmented, distoseptate (not partitioned side-to-side by septa), with non-protruding hila borne on geniculate (bent-knee) conidiophores
56
Q

Exserohilum rostratum

A
  • Cause of subcutaneous infections, sinusitis, and keratitis
  • Large, brown-pigmented, thick-walled, multi-celled conidia with disto-septa produced on geniculate conidiophores
  • ASSOCIATED WITH COMPOUNDED PHARMACEUTICAL [STEROID] PRODUCTS CONTAMINATED WITH DUST/DIRT
  • USED FOR INFECTIONS INTO LUMBAR SPINE AND KNEE JOINTS FOR PAIN MANAGEMENT
  • MENINGITIS SPINAL ABSCESS
  • SYNOVIAL INFECTIONS
57
Q

Curvularia lunata

A
  • Major etiologic agent of keratitis, sinusitis, and deep infection especially in immuno-compromised patients
  • Holoblastic conidia curved, occasionally straight, several-celled, smooth or verrucose, with protuberant hilum produced on geniculate conidiogenous cells
58
Q

Phaeoacremonium parasiticum

A

MACRO: cream-colored and velvety becomes grayish beige to olive-brown. clusters or aerial hyphae. Reverse is tan to brown

MICRO: Phialides along hyphae or on branched or unbranched conidiophores. Slightly tapering towards the apex. Basal septum and a collarette that is small and tubular or vaguely funnel shaped. Conidia are hyaline, oblong, some curved – gathered in clusters at end of phialide

59
Q

Chaetomium

A
  • Respiratory sites
  • Can cause nail and skin infection
  • Severe cases – nervous system
  • Can produce toxins
  • Dematiceous
  • Velvety texture (5 days growth), sandy in color; reverse tan or darker brown/black
  • Microscopic: brown, septate hyphae, large fruiting body – perithecium, which develops to ostiole, release ascospores
60
Q

Phoma glomerata

A
  • For subcutaneous nodules, surgery
  • Itraconazole - excellent and used the most
  • voriconazole and posaconazole
  • Duration of therapy: 6 wk to > 12 months
  • Amphotericin B is often ineffective
  • For brain abscess, include surgical resection if possible.
  • For brain abscess or disseminated infections, combination therapy (eg, with 2 or 3 drugs, at least one of which is an azole)

Microbiology (17 decks)

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