Mycology

Question 1

Types of fungi?

Answer 1

Mold: filamentous form of fungi
Yeast: oval-shaped, single-celled form of fungi
Dimorphic fungi: fungi that can grow both as a mold and as a yeast
Dematiaceous fungi: black or brown pigmented fungi
Phaeohyphomycosis – infections caused by dematiaceous fungi

Question 2

Hyphae and main examples

Answer 2

filaments or tubular structures of molds
* Septated (cross walls) - Aspergillus
* Non-septated (no cross walls or bundles) - Mucor
* Pseudohyphae (incomplete budding) - Candida Albicans

Question 3

Conidia

Answer 3

Spores extending (Aspergillus)

Question 4

Sporangiospores

Answer 4

Spores enclosed (Mucormycetes)

Question 5

Blastoconidia

Answer 5

Budding yeast cell (Blastomyces dermatitidis)

Question 6

Microconidia & macroconidia

Answer 6

1 or more conidia (differentiate Dermatophytes)

Question 7

Agar used for dermatophytes vs Agar for Candida

Answer 7

Sabouraud’s agar = Dermatophytes… low pH

CHROMagar = candida… different species are diff colors

Question 8

KOH stain

Answer 8

Used for skin scaping

Question 9

Gomori’s methenamine silver

Answer 9

Aseptated hyphae

Question 10

List Superficial & cutaneous fungi

Answer 10

• Dermatophytosis
• Candidiasis
• Tinea versicolor
• Tinea nigra
• Piedra

Question 11

Subcutaneous

Answer 11

• Sporotrichosis
• Chromoblastomycosis
• Mycetoma

Question 12

Systemic/Endemic

Answer 12

• Coccidioidomycosis
• Histoplasmosis
• Blastomycosis
• Paracoccidioidomycosis

Question 13

Systemic/
Opportunistic

Answer 13

• Cryptococcosis
• Candidiasis
• Aspergillosis
• Mucormycosis
• Pneumocystis

Question 14

Malassezia furfur aka ( Tinea Versicolor)

Answer 14

Still called Pityriasis
* Normal flora on Oily parts of skin, Lipophilic
* Dimorphic (Spaghetti & Meatballs)
*Light (hypopigmented) or coppery brown lesions
* Dandruff - flaky, white to yellowish scales

Question 15

Dermatophytes

Answer 15

Causes types of ringworm
* Identified by macro/micro conidia
* Some transmitted person to person
* Microsporum show up under UV lught

Question 16

Sporotrichosis aka. ( Sporothrix schenkii)

Answer 16

• Sub-cutaneous
• Dimorphic found in soil
• Disease of gardners
• Painless papule that spread along lymph

Question 17

Endemic characteristics:

Answer 17

Dimorphic
Transmission by inhalation
Histo Capsulatum and Blasto dermatitidis can resemble TB

Question 18

Blastomyces dermatitidis

Answer 18

*Dimorphic, but grows as extracellular yeast in tissue
* Can disseminate to skin forming ulcers
* Found in woods near lakes and rivers - middle to east U.S.

Question 19

Histoplasma capsulatum

Answer 19

In soil of bird or BAT droppings
Intracellular yeast
No capsule and proliferates in macrophages
Middle/eastern U.S.

Question 20

Paracoccidioides brasiliensis

Answer 20

Grows in sub-tropical rainforests
* Blastoconidia (like blastomyces)
* Budding forms a pilot’s wheel

Question 21

Coccidioides immitis & posadasii

Answer 21

AKA Valley Fever
* Likes dry, semi arid regions
South US to central america
* Transmission by inhaling Arthroconidia

Question 22

Candida sp.

Answer 22

Candida albicans most common species
* Pseudohyphae
* Germ tubes used to determine C. Albicans
* C. Auris shows drug resistance
* Causes white thrush in mouth, esoph, vagina and skin

Question 23

Cryptococcosis (neformans/gatti)

Answer 23

*Encapsulated yeast
* Pigeon droppings
* Disseminates to CNS (AIDs defining illness)
* Prep is India ink

Question 24

Asperigillosis

Answer 24

Ubiquitous mold
* Example of Septated hyphae w/ chains of conidia on a conidiophore
* Respiratory as well as blood and catheter sites

Question 25

Mucormycosis

Answer 25

Ubiquitous mold
* Inhaled from spoiled bread/foods
Rhinocerebral disease (in acidotic diabetics)
Pulmonary disease in immunocompromised