E2- Fungal Infections

Question 1

What are the two types of cutaneous fungi?

Answer 1

Malassezia furfur

Hortaea weneckii

Question 2

What do dermatophytes require for growth?

Answer 2

Keratin (hair, nails, skin; do not infect mucosal surfaces)

Question 3

Which fungi genuses have sexual spores?

Answer 3

Microsporum

Trichophyton

Question 4

What is the infective stage of fungal disease?

Answer 4

Arthroconidium

Question 5

What can be used to visualize arthroconidium microscopically?

Answer 5

10% KOH wet mount

Question 6

What is trichophytin

Answer 6

Galactomannan peptide
Crude antigen of dermatophytes
CHO component immediate response
Peptide component delayed response

Question 7

What kind of medium allows for early detection of a dermatophyte infection?

Answer 7

Dermatophyte test medium

Selective and differential

Question 8

What color will dermatophytes appear on DTM media?

Answer 8

Red color change
Dermatophytes utilize nitrogenous compounds over carbohydrates 
Change pH (alkaline)

Question 9

What class of dermatophytes have animal pathogens that can be transmitted to people?

Answer 9

Zoophilic

Question 10

What class of dermatophytes spread through human transmission?

Answer 10

Antrophophilic

Question 11

What class of dermatophytes are transmitted through soil to people and usually invade non-viable keratinized tissue?

Answer 11

Geophilic

Question 12

What area of the body do dermatophytes usually inhabit?

Answer 12

Moist areas

Question 13

What are some risk factors for dermatophyte infections?

Answer 13

Communal bathing facilities, immunocompromised status, Cushing’s syndrome, contact sports

Question 14

Disseminated dermatophyte disease is possible in what type of patients?

Answer 14

HIV

Question 15

What is an allergic dermal reaction to fungal antigens occurring in areas devoid of organisms?

Answer 15

Dermatophytid reaction

Question 16

What is the most common Dermatophytid infection?

Answer 16

Tinea pedis

Question 17

Are Dermatophytid spores generally susceptible or resistant to common disinfectants, chlorine, bleach, and detergents?

Answer 17

Susceptible

Question 18

What 3 Trichophyton species are most common?

Answer 18

Trichophyton tonsurans
Trichophyton rubrum
Trichophyton mentagrophytes

Question 19

Are Trichophyton species typically fluorescent or non fluorescent?

Answer 19

Non fluorescent

Question 20

What Dermatophytid species all make pencil-shaped macroconidia with thin walls?

Answer 20

Trichophyton species

Question 21

What do Trichophyton species produce?

Answer 21

Hyphae (Spindle-shaped)
Microconidia
Macroconidia

Question 22

What are species are the most common cause of tinea capitis?

Answer 22

Microsporum species

Microsporum canis

Question 23

Are Microsporum species typically fluorescent or non fluorescent?

Answer 23

Fluorescent

Question 24

What do Microsporum species produce?

Answer 24

Hyphae
Microconidia
Macroconidia (large, spindle-shaped, multicellular, thick walled)

Question 25

What is infected in tinea barbae?

Answer 25

Beard

Question 26

What is infected in tinea manus?

Answer 26

Hand

Question 27

What is infected in tinea ungium?

Answer 27

Nails (onychomycosis)

Question 28

What is most common causative agent of tinea capitis?

Answer 28

Microsporum canis

Question 29

What are the two varieties of tinea capitis?What species cause each?

Answer 29

Endothrix- Trichophyton | Ectothrix- Microsporum

Question 30

How does black dot tinea capitis occur?

Answer 30

Occurs when infected hair breaks off leading to alopecia

Question 31

Can tinea capitis be zoonotic?

Answer 31

Yes

Question 32

What are the most common causative agents of tinea pedis?

Answer 32

Epidermophyton floccosum Trichophyton mentagrophytes Trichophyton rubrum

Question 33

What are the most common causative agents of tinea corporis and tinea cruris?

Answer 33

Microsporum canis Epidermophyton floccosum Trichophyton mentgrophytes Trichophyton rubrum

Question 34

What are some predisposing factors for tinea corporis and tinea cruris?

Answer 34

Diebetes Obesity Excessive persiration

Question 35

How is tinea corporis and tinea cruris transmitted?

Answer 35

Direct and indirect contact | towels, clothing, bed linens

Question 36

What are the most common causative agents of tinea unguium?

Answer 36

Epidermophyton floccosum Trichophyton mentagrophytes Trichophyton rubrum

Question 37

What is the most commonly encountered opprtunistic mycoses (fungal/yeast infection) worldwide?

Answer 37

Candidiases

Question 38

Does Candida albicans have many virulence factors?

Answer 38

No

Question 39

What form Candida albicans is more adhesive than the parental yeast cells?

Answer 39

Germ tube

Question 40

How is Candida albicans dx?

Answer 40

Direct microscopic examination

Question 41

Candida are polymorphic fungus that can grow as what?

Answer 41

Budding yeast Pseudohyphae Germ tube True hyphae

Question 42

What type of agar used to dx Candida infections?

Answer 42

Chromagar

Question 43

What can be used to determine the species of a Candida infection?

Answer 43

Serology to detect presence/absence of germ tubes

Question 44

What two Candida species have germ tubes?

Answer 44

Candida albicans | Candida dubliniensis

Question 45

What is the causative agent of tinea verisolor?

Answer 45

Malassezia furfur

Question 46

What does Malassezia furfur look like under microscopy?

Answer 46

Short unbranched hyphae and spherical cells | "Spaghetti and meatballs"

Question 47

Which pathogen has a lipophilic growth factor? What does this mean?

Answer 47

Malassezia furfur | Requires fat to grow (commonly sebaceous glands)

Question 48

How is tinea versicolor dx?

Answer 48

KOH prep and microscopy

Question 49

What is the causative agent of Tinea nigra?

Answer 49

Hortaea weneckii

Question 50

Is Tinea nigra caused by yeast or mold?

Answer 50

Dimorphic species that can grow as yeast and/or mold

Question 51

What type of conditions can Hortaea weneckii grow in?

Answer 51

Saturated salt solutions | Extremely halotolerant

Question 52

What is the clinical presentation of Tinea nigra?

Answer 52

Brownish lesions | Fungus produces melanin

Question 53

How is Tinea nigra dx?

Answer 53

KOH prep and microscopy

Question 54

What is a structure unique to dermatophytes?

Answer 54

Trichophytin