Block 3 Micro Exam -- Mycology Lectures

Front 1

Distinguishing characteristics of fungi

Back 1

Absorptive Nutrition
LACK chlorophyll
Maintain cell wall (3 layers) throughout life cycle
ERGOSTEROL

Front 2

Yeasts vs. Moulds

Back 2

YEASTS -- unicellular, round, budding or fission
MOULDS -- multicellular, filamentous, spores or conidia

Front 3

Dimorphic growth

Back 3

Grows as BOTH mould and fungi

MOULD -- 28-30 degrees C
YEAST -- 37 degrees C
EXCEPTION -- Coccidioides (form spherules)

Front 4

Primary genus of CAPSULAR fungi

Back 4

Cryptococcus

Front 5

Superficial mycoses

Back 5

Piedras
Tinea Nigra
Pityriasis Versicolor (most common)

Front 6

Pityriasis Versicolor

Back 6

Caused by Malassezia (globosa, furfur)
Suntan lotions (organisms are LIPOphilic)
Common in adolescents and YOUNG adults

Note: Malassezia also causes folliculitis in AIDS pts.

Front 7

Microscopic appearance of M. Furfur

Back 7

Spaghetti and Meatballs

Front 8

Most common fungal disease

Back 8

Dermatophytosis (ringworm)

Front 9

Three genera of dermatophytes

Back 9

Microsporium
Trichophyton (distinguished by vitamin requirements)
Epidermophyton floccosum (does NOT cause scalp disease)

Front 10

Tinea Capitis

Back 10

Scalp, eyebrows, eyelashes
Associated with POOR HYGIENE
Microsporium and Trichophyton, NOT Epidermophyton

Ectothrix -- invasion of follicle, but NO hair penetration
Endothrix -- penetration of hair

Front 11

Tinea Corporis

Back 11

Classic ringworm
Glabrous (smooth, no hair) skin

Front 12

Tinea Cruris

Back 12

Jock itch
Epidermophyton floccosum
MUST be distinguished from Candida infection

Front 13

Tinea pedis

Back 13

Ball of feet & interdigital areas
Trichophyton and Epidermophyton
Acute form is better

Front 14

Id Reaction

Back 14

Vesicles found distant from the site of infection
Often associated with Tinea Pedis

Front 15

Tinea unguium

Back 15

Nail infection
Chronic

Front 16

Tinea barbae

Back 16

Bearded area of face
Similar to T. capitis, BUT much more inflammatory

Relieved by removal of beard

Front 17

Mycosel culture medium

Back 17

Contains cycloheximide and chloramphenicol
Inhibits bacteria

Front 18

General treatment for dermatophytosis

Back 18

Topical -- azoles, tolnaftate, salicylate

Front 19

Treatment for recalcitrant onychodermatomycosis

Back 19

Griseofulvin and Terbinafine (Lamisil)

Front 20

Sporotrichosis
("Rose-Handler's Disease")

Back 20

Sporothrix schencki

Dimorphic ("rose petal" mould, "cigar" yeasts)
ASTEROID BODY is almost pathognomonic
Found in soil, wood, moss
Can be inhaled (AIDS)

Common form is lymphocutaneous
ASCENDS up lymphatics (stops @ shoulder)

Front 21

Treatment for Sporotrichosis

Back 21

Itraconazole
Amp B for life-threatening disease
Saturated solution of KI for cutaneous disease

Front 22

Chromoblastomycosis
(Verrucous Dermatitis)

Back 22

Pigmented fungi (melanin)
Hyperplasia limited to SUBcutaneous areas
"Muriform sclerotic cells" -- COPPER PENNIES

Treatment same as Phaeohyphomycosis (surgery, amp B)

Front 23

Phaeohyphomycosis

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All other forms of what once was chromoblastomycosis
NO muriform cells (NO "copper pennies")
Disease usually in feet and legs
Some agents can infect brain

Treatment -- Surgery, Amp B, Itraconazole

Front 24

Agents of Phaeohyphomycosis that can spread to brain

Back 24

Cladophialophora BANTIANA
BIPOLARIS

Front 25

Eumycotic Mycetoma

Back 25

Soil fungi through skin
Destruction of bone and muscle

TRIAD -- tumefaction, draining sinus tracts, granules

Front 26

Candida species that does NOT form pseudohyphae

Back 26

Candidiasis Glabrata

Front 27

Diseases caused by Candida

Back 27

Vaginitis (most common)
Oral Thrush (2nd most common)
Cutaneous & systemic Candidiasis

Front 28

Candida species that is most virulent in cancer pts.

Back 28

Candida tropicalis

Front 29

Germ tube test

Back 29

Presumptive test for Candida
Germ tube within 2 hours indicative of C. Albicans

Front 30

Defect predisposing to mucocutaneous candidiasis

Back 30

Functional PMNs, but low CD4

Front 31

Defect predisposing to systemic candidiasis

Back 31

Neutropenia

Front 32

Cryptococcosis

Back 32

Cryptococcus Neoformans

CAPSULE -- galactoxylomannan polysaccharide
Pigeon droppings (needs high N content)
Meningitis is most common complication
Can disseminate to skin and bone
Assoc. with collagen diseases
INDIA INK
Fibrotic changes -- X-ray MAY not be useful

Treatment -- Amp B & fluconazole

Front 33

Subcutaneous mycoses

Back 33

Sporotrichosis
Phaeohyphomycosis
Eumycotic Mycetoma
Chromoblastomycosis

Front 34

Yeast Infections

Back 34

Candidiasis
Cryptococcosis

Front 35

Systemic fungi

Back 35

Histoplasma
Paracoccidioides
Blastomcyes
Coccidioides

Front 36

Systemic fungus with MORE frequent calcification

Back 36

Histoplasmosis

Front 37

Fungi with which caseation is LESS common

Back 37

Paracoccidioides
Blastomycosis

Front 38

Histoplasmosis
("Spelunker's disease")

Back 38

Histoplasma capsulatum

Worldwide
In U.S.: Miss./Ohio River Valleys, Midwest, Va., Md.
Identify by micro/macroconidia (tuberculated)
Important problem in AIDS
Bird droppings (high N content)
Infections follow inhalation of spores/mycelium
Can mimic Tb
Grow INTRACELLULARLY in histiocytes
More frequent calcification -- COIN LESIONS

Treatment -- Amp B, Itraconazole

Front 39

Only true intracellular fungal pathogen

Back 39

HISTOplasmosis

Front 40

Blastomycosis

Back 40

Blastomyces Dermatitidis

East of Miss., Miss./Ohio River Valleys
Inhaled microconida (soil enriched with wood [beaver DAMS])
Disease more frequently seen in DOGS
Can disseminate to skin and bone (skin > bone)

Budded yeast with a Broad Based Bud (BBBB)

Treatment -- Amp B, Itraconazole, Ketoconazole

Front 41

Coccidioidomycosis
(San Joaquin Valley Fever)

Back 41

Coccidioides Immitis & C. Posadasii

Southwest USA, Northern Mexico, South America
RACE DEPENDENT: Filipinos > Blacks > Whites
Septated, filamentous fungus in desert soil
SPHERULES filled with ENDOSPORES
Allergic reactions -- Desert Bumps, Desert Rheumatism
Can show coin lesions, BUT X-ray may not be helpful
Disseminated -- reactivation due to steroid therapy (can cause meningitis)

Treatment -- Amp B INITIALLY, then fluconazole/itraconazole

Front 42

Paracoccidioidomycosis

Back 42

Paracoccidioides BRASILensis
Central and South America

Identify by microconidia (PILOT's WHEEL)
Causes oral lesions
Primary pulmonary disease (disseminates)

Treatment -- Amp B with sulfa drugs, Itraconazole

Front 43

Places Histoplasmosis can disseminate

Back 43

Spleen, Liver, Adrenals, BM, eye orbit, lymph nodes

Front 44

Places Paracoccidioidomycosis can disseminate

Back 44

Spleen, Intestines, Liver, Skin

Front 45

Penicillosis

Back 45

Penicillium Marneffei

Southeast Asia

Front 46

Causes of Zygomycosis

Back 46

Rhizopus
Absidia
Mucor

Front 47

Polyenes

Back 47

FungiCIDAL
Bind ergosterol, disrupting membrane (form pores)
Ex. -- Amp B, Nystatin, Natamycin (ophthalmic only)

Resistance -- lack of ergosterol in membrane

Front 48

Amphotericin B
("Amphoterrible")

Back 48

FungiCIDAL polyene that binds ergosterol

Agent of choice against systemic disease (life threatening)
I.V. (oral formulation has limited use)
SIDE EFFECTS -- nephrotoxicity

Lipid formulation decreases toxicity
-- Does NOT increase efficacy --

Front 49

Aministration routes for Nystatin

Back 49

Used topically and orally (NOT absorbed well)

Front 50

Azoles

Back 50

Generally, NOT fungicidal
Agents of choice for NON-life threatening diseases
Inhibit C-P450 dependent demethylation of lanosterol
PREVENT ergosterol synthesis
Ex. -- Fluconazole, Itraconazole, Ketoconazole

Resistance -- multiple mechanisms, upregulation of MDR pores

Front 51

Allylamines

Back 51

Cidal for some organisms
Used primarily for DERMATOPHYTOSIS

INHIBIT SQUALENE EPOXIDASE

Generate toxic accumulation of squalene
Ex. -- Naftifine, Terbinafine

Resistance -- target mod., poor penetration, overprod. of target

Front 52

Candins

Back 52

Drugs used primarily for CANDIdiasis

Inhibit synthase of cell wall
Actual targets are synthase regulatory proteins
Ex. -- Caspofungin, Micafungin

Resistance -- modified targets

NOT effective against Crypto, Zygomycetes, Fusarium

Front 53

Nucleoside Analog

Back 53

Inhibits nucleotide synthesis
Converted to 5-FLUOROURICIL in cytoplasm

Resistance -- developed rapidly

Front 54

Nikkomycins

Back 54

Anti-fungals that work against Coccidioidomycosis

Front 55

Kirby-Bauer Assay

Back 55

Agar is impregnated with antibiotics
Scale relates clearance to min. inhibitory conc. (MIC)

Front 56

Anamorph

Back 56

ASEXUAL form in fungal life cycle

Front 57

Conidia

Back 57

ASEXUAL spores of fungus

Front 58

YEAST that causes a fibrotic response
(May be X-ray transparent)

Back 58

Cryptococcus
(also can be case with Coccidioides)