5.46 Part A

Question 1

Fungi
characteristics (3)

Answer 1

Eukaryotes
Spore-forming
No chlorophyll

Question 2

Most fungi are —

Answer 2

aerobic

some facultative and strict anaerobes

Question 3

Cell walls usually contain —

Answer 3

chitin

Question 4

chitin

Answer 4

polysaccharide containing N-acetylglucosamine (NAG)

Question 5

Two growth forms

Answer 5

1. filamentous (molds)

2. unicellular (yeasts)

Question 6

1. filamentous (molds)

4

Answer 6

threadlike filaments =hyphae
mycelium = mass of hyphae
septate vs. coenocytic hyphae
(with and without crosswalls)
grow by extension of tip and branching

Question 7

2. unicellular (yeasts)

3

Answer 7

single cells (ovoid or spherical)
reproduce asexually by cell division (budding)
sexually by cell fusion and spore formation

Question 8

Reproduction

1. asexual (2)

Answer 8

a. cell division

b. spore formation

Question 9

cell division (2)

Answer 9

budding or transverse division

Question 10

Reproduction

2. sexual

Answer 10

involves production of “sexual spores” by meiosis of a diploid cell

Question 11

Anamorph:

Answer 11

form producing asexual spores,

often mold-like growth form

Question 12

Teleomorph:

Answer 12

form producing sexual spores,

typically a fruiting body

Question 13

dimorphism -

Answer 13

ability to grow as yeast form or mold form

Question 14

many pathogenic fungi are

Answer 14

dimorphic

yeast form more typical at human body temperature
Candida is exception to this
both forms of Candida exist inside and outside the body

Question 15

Candida actually forms (2)

Answer 15

pseudohyphae and pseudomycelia

Question 16

pseudohyphae -

Answer 16

hyphal growth is a modified budding where newly

budded cells remain attached to mother cell

Question 17

some pathogenic fungi are not dimorphic
Aspergillus -
Cryptococcus neoformans -

Answer 17

mold from only

yeast form only

Question 18

Mycoses -

Answer 18

fungal infections
Classified by affected area of body

Superficial
Cutaneous
Subcutaneous
Systemic

Question 19

Primary mechanisms for fighting fungi:

2

Answer 19

Neutrophil phagocytosis and killing

T cell-mediated immunity

Question 20

Superficial mycoses (3)

Answer 20

keratinized outer layers of skin, hair, and nails
Mild infections/minimal inflammatory response
Easy to treat or clears without treatment

Question 21

Piedras (2)

Answer 21

infections of hair shaft
Trichosporon beigelii
white piedra

Question 22

Tineas (3)

Answer 22

infections involving outer layers
of skin, nails, and hair
Malassezia furfur (skin)
Pityriasis versicolor

Question 23

most occur in —

Answer 23

tropics

Question 24

Pityriasis (tinea) versicolor (2)

Answer 24

Disease found worldwide
Pigmented macules - not elevated
but altered color

Question 25

Malassezia furfur | characteristics (2)

Answer 25

M. furfur not found in the environment | Human-to-human transmission

Question 26

Cutaneous mycoses

Answer 26

keratinized outer layers of skin, hair, and nails

Question 27

Cutaneous mycoses | Skin infections:

Answer 27

no invasion beyond stratum corneum (outermost layer of epidermis) BUT a more apparent host response is elicited (unlike superficial mycoses)

Question 28

"Dermaphytes” (4)

Answer 28

Microsporum Trichophyton Epidermophyton Keratinophilic and keratinolytic

Question 29

Cutaneous mycoses | Cause

Answer 29

tineas (”ringworm")

Question 30

Tinea pedis =

Answer 30

athlete's foot

Question 31

Tinea cruris =

Answer 31

jock itch

Question 32

tineas | Characterized by

Answer 32

inflammation | ring of inflammatory scaling

Question 33

Cutaneous mycoses | transmission

Answer 33

Person-to person transmission Some are soil organisms Others are zoonoses

Question 34

Cutaneous mycoses | Diagnosis by

Answer 34

microscopy of samples

Question 35

Subcutaneous mycoses | 3

Answer 35

dermis and subcutaneous tissue Do not respond well to antifungal chemotherapy Need to excise

Question 36

Subcutaneous mycoses Sporotrichosis (3)

Answer 36

Sporothrix schenkii Thorns and splinters Responds to oral potassium iodide

Question 37

Systemic mycoses:

Answer 37

invade internal organs

Question 38

Systemic mycoses: | caused by

Answer 38

endemic dimorphic fungal pathogens

Question 39

saprobe -

Answer 39

organism living on dead or decaying matter

Question 40

Histoplasma capsulatum

Answer 40

Histoplasmosis

Question 41

Blastomyces dermatitidis

Answer 41

Blastomycosis

Question 42

Coccidioides immitis

Answer 42

Coccidioidomycosis

Question 43

Spherule

Answer 43

(100s of endospores)

Question 44

Histoplasma capsulatum | 2

Answer 44

Bird or bat droppings (high nitrogen content) | Acquire fungus by inhalation of conidia

Question 45

Histoplasma capsulatum | Organism remains viable within

Answer 45

macrophages

Question 46

Histoplasma capsulatum | modulate pH of

Answer 46

phagolysosome

Question 47

Histoplasma capsulatum Antibody plays no role in --- (2) are important for immunity

Answer 47

resolution Cell-mediated immune system of CD4 T lymphocytes and activated macrophages

Question 48

Histoplasma capsulatum | Primary infections most often ---

Answer 48

asymptomatic

Question 49

Histoplasma capsulatum | Granulomas develop in lung with

Answer 49

caseous necrosis (plus calcification) reactivation infection can occur years later

Question 50

Histoplasma capsulatum | tx

Answer 50

3-12 months of antifungal agent

Question 51

Blastomyces dermatiditis Found in --- Acquire fungus by ---

Answer 51

``` decaying matter (e.g leave litter) inhalation of conidia ```

Question 52

Blastomyces dermatiditis (2) are important for immunity

Answer 52

Cell-mediated immune system of CD4 T | lymphocytes and activated macrophages

Question 53

Blastomyces dermatiditis Primary infections symptomatic in <--% of patients

Answer 53

50

Question 54

Blastomyces dermatiditis | Granulomas develop with

Answer 54

caseous necrosis (plus calcification) reactivation infection can occur years later

Question 55

Blastomyces dermatiditis | --- lesions are a hallmark of disease

Answer 55

Cutaneous heaped up borders and small, central microabscesses

Question 56

Blastomyces dermatiditis | Diagnosis

Answer 56

``` histopathological examination (thick-walled yeasts with single broad-based bud) ```

Question 57

Blastomyces dermatiditis | tx

Answer 57

6-12 months of antifungal agent

Question 58

Coccidioides immitis | characterizations (2)

Answer 58

Southwestern USA = lower Sonoran life zone | Huge “blooms”

Question 59

Coccidioides immitis --- is primary target but the fungus spreads through the --- and infects many organs

Answer 59

Lung | circulatory system

Question 60

Coccidioides immitis | symptoms

Answer 60

Usually no symptoms | - cell-mediated immunity

Question 61

Coccidioides immitis Sometimes (3)

Answer 61

acute pulmonary infection arthralgias and skin lesions Disseminated coccidioidomycosis

Question 62

arthralgias and skin lesions

Answer 62

“desert rheumatism” or “valley fever"

Question 63

Disseminated coccidioidomycosis

Answer 63

chronic meningitis -fatal if not treated (lifelong)

Question 64

Coccidioides immitis | histopathology -

Answer 64

presence of spherules

Question 65

Coccidioides immitis | tx

Answer 65

12-24 months