Systemic/Cutaneous Mycoses, Opportunistic Fungi

Question 1

Systemic Mycoses

List the 5 types of Systemic dimorphic fungi

Answer 1

1. Blastomyces dermatitidis
2. Coccidioides immitis
3. Histoplasma capsulatum
4. Paracoccidiodes brasiliensis
5. Talaromyces marneffei

Pneumocystis jirovecci is in the Systemic Mycoses slideshow too and is considered dimorphic. I don’t know why it’s not in this list in the PPT

Question 2

Systemic Mycoses

Which diseases do the 5 systemic dimorphic fungi cause?

Answer 2

1. Blastomycosis
2. Coccidiodomycosis
3. Histoplasmosis
4. Paracoccidiodomycosis
5. Talaromycosis

Question 3

Describe Blastomyces dermatitidis characteristics

Answer 3

• Fungus lives in moist soil and decomposing matter (saprophytic)
• In USA, lives in Ohio and Mississippi River Valleys, Great Lakes, and the Saint Lawrence River
• Not spread from person to person
• Infection caused by breathing in fungal spores
• People who smoke, have lung disease, or are immunocompromised are more likely to get sick

Question 4

Systemic Mycoses

Describe Coccidioides spp. traits

Answer 4

• BSL-3 organism
• Risk to hospital personnel
• Known as Valley Fever
• Found in San Joaquin Valley + Sonoran Desert
• Lives in dust and soil of desert regions
• Infection due to breathing in fungal spores
• Exists as mold with septate hyphae that fragment into arthroconidia

Question 5

Describe Histoplasma capsulatum traits

Answer 5

• Found in chicken coops and bat caves
• Exists as mold with aerial hyphae, which produce macroconidia and microconidia
• Infection due to breathing in fungal spores
• Inside body, warmer host temp signals fungus to transofsrm in to yeast, which get phagocytosed by immune cells

Question 6

Systemic Mycoses

Describe Talaromyces marneffei traits

Answer 6

• Only affects people who live in Southeast Asia, southern China, or eastern India
• Makes people sick week to years after primary contact with the fungus
• Mostly affects immunocompromised patients (e.g., HIV/AIDS)

Question 7

Systemic Mycoses

Describe Paracoccidiodes brasiliensis traits

Answer 7

• Mariner’s wheel
• Found in Central and South America
• Lives in moist soil
• Infection due to breathing in spores from air
• Mostly affects men who work outdoors

Question 8

Systemic Mycoses

Describe Pneumocystis jirovecii traits

Answer 8

• Formally considered protozoan, now considered fungus
• Pneumocystis pneumonia (PCP
• PCR test or microscopic exam
• Respiratory specimens (BAL: bronchioalveolar lavage or biopsy)

Question 9

Yeasts

List clinically significant yeast

Answer 9

1. Candida albicans
2. Candida auris
3. Other Candida spp.
4. Cryptococcus neoformans/gatii
5. Trichosporon beigelii
6. Rhodotorula
7. Geotrichum candidum
8. Malassezia spp.

Question 10

Yeasts

Why is Candida auris a public health concern?

Answer 10

• Multidrug resistant
• Difficult to ID in lab
• Has caused outbreaks in clinical settings

Question 11

Yeasts

Describe Candida spp. traits

Answer 11

• Normally lives on skin and inside the body, such as the mouth, throat, gut, and vagina, without causing problems
• Candida can cause infections if it grows out of control or if it enters deep into the body
• Can infect mouth, throat, esophagus, and vagina

Question 12

Yeasts

List other Candida spp.

Answer 12

1. C. glabrata
2. C. tropicalis
3. C. krusei
4. C. parapsilosis
5. C. auris

Question 13

Yeasts

Describe Cryptococcus neoformans traits

Answer 13

• Produces phenoloxidase (produces melanin)
• Infection due to inhalation of spores , which lodge into alveoli and disseminate into CNS
• Spores found in bird excreta, such as pigeons
• Tests: urease and bird seed agar
• Antigen detection: CSF or serum detects early, asymptomatic infection in HIV-infected patients

Question 14

Yeasts

Describe Cryptococcus gattii traits

Answer 14

• Lives in the environment in primarily tropical and sub-tropical areas of the world but also in some temperate regions such as British Columbia and some parts of the United States.
• Rare infection that people can get after breathing in the microscopic fungus
• Can affect the lungs, central nervous system, or other parts of the body.

Question 15

Yeasts

What is the procedure for C. neoformans ID?

Answer 15

1. Observe mucoid colonies in preliminary culture
2. Urease test -> must be positive
3. Observe morphology cornmeal agar -> want absent pseudohyphae
4. Inoculate onto bird seed agar
5. Observe reddish-brown colonies

Question 16

Yeasts

Describe Malassezia furfur traits

Answer 16

• Requires olive oil in media for growth bc lipid-dependent
• ## Causes superficial skin infection called tinea versicolor

Question 17

Cutaneous Mycoses

Define superficial mycoses

Answer 17

Infections that involve the outer epithelial layers (skin, hair, and nails)

Question 18

Cutaneous Mycoses

Define cutaneous mycoses

Answer 18

Infection within the skin, hair, and nails

Question 19

Cutaneous Mycoses

Define subcutaneous mycoses

Answer 19

Infection beneath the skin. Often due to implantation

Question 20

Cutaneous Mycoses

Define dermatophyte

Answer 20

Group of fungus that causes infection of the skin, hair, and nails

Question 21

Cutaneous Mycoses

List the 4 superficial mycoses + the infections they cause

Answer 21

1. Malassezia furfur = Tinea versicolor
2. Hortaea werneckii = Tinea nigra
3. Piedra hortaaea = Black Piedra
4. Trichosporon = White Piedra

Question 22

Cutaneous Mycoses

List the 3 dermatophytes and where they infect

Answer 22

1. Trychophyton = skin, hair, and nails
2. Epidermophyton = Skin and nails
3. Microsporum = Hair and skin

Question 23

Cutaneous Mycoses

List the dermatophytes that cause tinea pedis (athlete’s foot)

Answer 23

1. Epidermophyton
2. Trichophyton

Question 24

Cutaneous Mycoses

List the dermatophytes that cause tinea corporis (ringworm)

Answer 24

1. Microsporum
2. Trichophyton

Question 25

# Cutaneous Mycoses List the dermatophytes that cause **tinea unguium or onchomycosis** (Nail infection)

Answer 25

1. *Epidermophyton* 2. *Trichophyton*

Question 26

# Cuteaneous Mycoses List the dermatophytes that cause **tinea capitis** (scalp infection)

Answer 26

1. *Microsporum* 2. *Trichyphyton*

Question 27

# Cutaneous Mycoses *Microsporum audouinii* almost always infects which demographic group?

Answer 27

Children

Question 28

# Cutaneous Mycoses What are two important *Trichophyton* species?

Answer 28

1. *rubrum* (hair perforation test negative) 2. *tonsurans*

Question 29

# Cutaneous Mycoses Name dermatophyte ID/differentiation tests

Answer 29

1. Hair perforation test to see if fungi penetrates hair 2. Urease test (pink means positive) 3. Thiamine test (test if thiamine is present or not)

Question 30

# Cutaneous mycoses Causative fungi of subcutaneous mycoses?

Answer 30

Soil saprophytes

Question 31

# Cutaneous Mycoses What are **dematiaceous molds**?

Answer 31

Dark brown/black pigmented colonies (produce melanin)

Question 32

# Cutaneous Mycoses What are **hyaline molds**?

Answer 32

Colorless hyphae with mainly filamentous form. Colonies may be brightly colored or colorless (this sentence is weird but it's on the slide)

Question 33

# Cutaneous Mycoses Sporotrichosis is also known as which disesase? Caused by which organism?

Answer 33

- Rose Gardener's disease - *Sporothrix schenkii* ## Footnote Forms lollipop flower structures Have melanin

Question 34

# Cutaneous Mycoses Describe Chromoblastomycosis and causative agent(s)

Answer 34

- Tropical disease that penetrates skin, grows deep, then resurfaces - Causative agents: *Fonsecaea pedrosi*, *Phialophora spp.*, *Cladophialophora spp..*, *Phaeohyphomycosis*

Question 35

# Cutaneous Mycoses What is the key trait to ID *Alternaria spp.*?

Answer 35

Cross-linking segments in conidiospores

Question 36

# Cutaneous Mycoses Describe *Bipolaris spp.* traits

Answer 36

- Melanin mold - Fewer segments (3-6 per spore) - Some melanin molds cause sinusitis

Question 37

# Cutaneous Mycoses Describe *Curvularia spp.* traits

Answer 37

- Spores have few segments and NO cross-linking - Causes sinusitis

Question 38

# Cutaneous Mycoses Define **Mycetoma**

Answer 38

a clinical syndrome of localized, tumorous lesions in cutaneous and subcutaneous tissues due to infections, often a foot, with actinomycetes or fungi (Pseudoallscheria boydii)

Question 39

# Opportunistic Mycoses Describe traits of opportunistic mycoses

Answer 39

- Infections generally through inhalation of conidia (asexual) - Most are saprophytic - Do NOT normally cause infections in healthy people but do cause disease in immunocompromised people

Question 40

# Opportunistic Mycoses List the most common opportunistic infections

Answer 40

- Candidiasis - Aspergillosis - Cryptococcosis - Zygomycosis

Question 41

# Opportunistic Mycoses Describe traits of *Aspergillus spp.*

Answer 41

- Common mold that we breathe in every day without getting sick - Antifungal resistance problem - Chronic obstructive lung disease - Allergic Aspergillous sinusitis - Cutaneous skin apsergillosis - Chronic pulmonary aspergillosis - Forms conidiospores

Question 42

# Opportunistic Mycoses List species of *Aspergillus*

Answer 42

- *fumigatus* - *niger* - *flavus*

Question 43

# Opportunistic Mycoses List Mucormycetes (aka Zygomycetes)

Answer 43

- *Cunninghamella spp.* - *Lichtheimia* - *Mucor spp.* - *Rhizomucor spp.* - *Rhizopus spp.* - *Syncephalastrum spp.*

Question 44

# Opportunistic Mycoses Which disease does *Fusarium spp.* cause?

Answer 44

Keratinitis (infects eyes)