Agents of Superficial Mycoses

Question 1

What specific part of the epidermis do superficial mycoses affect?

Answer 1

stratum corneum

Question 2

True or False.

Superficial mycoses induce an inflammatory reaction in the host.

Answer 2

False.

(Patients who suffer from superficial fungal infections do not show any overt symptoms because the fungal agents do not activate any tissue response or inflammatory reaction)

Question 3

Identify the causative agent.

Tinea versicolor
Pityriasis versicolor

Answer 3

Malassezia furfur

Question 4

Identify the causative agent.

Black piedra

Answer 4

Piedraia hortae

Question 5

Identify the causative agent.

White piedra

Answer 5

Trichosporon spp.

Question 6

Identify the causative agent.

Tinea Nigra

Answer 6

Hortaea werneckii

Question 7

Identify the causative agent.

dandruff

Answer 7

Malassezia furfur

Question 8

Identify the disease.

• pale patchy, scaling lesions
• “dandruff”
• more evident during warm months

Answer 8

Tinea versicolor / Pityriasis versicolor

Question 9

Identify the disease.

• on hairs of the scalp
• hard, dark brown to black gritty nodules that are firmly attached to the hair shaft.

Answer 9

Black piedra

Question 10

Identify the disease.

• on the hair shaft, face, and pubic region
• soft mycelial mat
• infect immunocompromised patients’ blood, CSF, and organs
• Endemic in tropical areas (South America, Africa, and parts of Asia)

Answer 10

White piedra

Question 11

Identify the disease.

• brown to black nonscaly macules
• on palms of hands and soles of feet

Answer 11

Tinea nigra

Question 12

What is the growth requirement for M. furfur?

Answer 12

lipids

Question 13

Specimen of choice for M. furfur

Answer 13

skin scrapings

Question 14

Identify the agent.

▪ 4-8 um budding yeats
▪ septate, branched hyphae
▪ “Spaghetti and Meatballs” fungus

Answer 14

Malassezia furfur

Question 15

Culture media for M. furfur

Answer 15

Fungal Culture Media + Olive Oil

Question 16

Describe the colonies of M. furfur

Answer 16

cream-colored, moist, and smooth

Question 17

What is the method of identification used for M. furfur that observes yellow fluorescence?

Answer 17

Wood’s lamp

Question 18

What is inside the hard, dark brown to black gritty nodules of a black piedra disease?

Answer 18

asci with 8 ascospores

Question 19

Laboratory diagnosis preparation for Malassezia furfur.

Answer 19

KOH preparation

Question 20

Identify the agent.

Thick-walled rhomboid cells containing ascospores

Answer 20

Piedraia hortae

Question 21

Culture media for Piedraia hortae

Answer 21

Sabouraud dextrose agar (SDA)

Question 22

Describe the colonies of Piedraia hortae.

Answer 22

brown, restricted colonies

Question 23

What has been described as an extremely variable human pathogen?

Answer 23

Trichosporon beigelii

Question 24

How many species are included in the Trichosporon spp.?

Answer 24

19

Question 25

What is the most important species of Trichosporon spp.?

Answer 25

Trichosporon asahaii

Question 26

What Trichosporon spp. causes systemic disease and is recovered frequently from the cerebrospinal fluid (CSF) as a cause of meningitis.

Answer 26

Trichosporon mucoides

Question 27

What species resembles the colonies of Trichosporon spp.?

Answer 27

Cryptococcus neoformans

Question 28

Enumerate the microscopic elements that can be seen on Trichosporon spp.

Answer 28

arthroconidia
hyphae
blastoconidia

Question 29

Identify the agent.

• Carbohydrate (-) Non-Fermenter
• Potassium Nitrate (+) Utilizer
• Urease (+)

Answer 29

Trichosporon spp.

Question 30

Laboratory diagnosis preparation for Hortaea werneckii.

Answer 30

10% to 20% KOH

Question 31

Identify the agent.

▪ septate hyphal elements
▪ Younger: budding cells (blastoconidia)
▪ Older: hyphae with blastoconidia in clusters
▪ Annelloconidia are seen in older hyphal colonies

Answer 31

Hortaea werneckii

Question 32

Describe the colonies of Hortaea werneckii.

Answer 32

shiny, moist, yeastlike colonies