Microbio Week 8 - Other Mycoses (Mini Exam)

Question 1

The greater the degree of immunocompromise, the more…

Answer 1

Invasive

Question 2

What are the 3 hyphal molds?

Answer 2

Aspergillus
Mucor
Dermatophytes

Question 3

What are the 3 dimorphic fungi?

Answer 3

Histoplasma
Blastomyces
Coccidioides

Question 4

What is the 1 yeast?

Answer 4

Cryptococcus

Question 5

Where do most fungi grow? How are they acquired?

Answer 5

Environment

Airborne dust containing spores

Question 6

What is the morphology of Aspergillus?

Answer 6

Filamentous mold
Septate hyphae (has cross walls)
Branching at 45 degree angle

Question 7

How does Aspergillus and Mucor reproduce?

Answer 7

Release spores from hyphae into air (airborne)

Question 8

Where can Aspergillus and Mucor grow?

Answer 8

Outside = on living & decaying organic matter
Inside = on damp, wet surfaces

Question 9

What are Aspergillus infections caused by?

Answer 9

Inhaling spores

Question 10

What is one of the most common causes of invasive fungal infections?

Answer 10

Aspergillus

Question 11

Which is more invasive: Aspergillus or Mucor?

Answer 11

Mucor

Question 12

How do you diagnose Aspergillus and Mucor infections?

Answer 12

Direct microscopic exam - 10% KOH or silver stain

Question 13

What are you looking for when doing a direct microscopic exam for Aspergillus infection?

Answer 13

Septate hyphae w/ 45 degree branching

Question 14

What are you looking for when doing a direct microscopic exam for Mucor infection?

Answer 14

Aseptate hyphae w/ 90 degree branching

Question 15

What is the response to treatment for Aspergillus dependent on?

Answer 15

of neutrophils

Competence of immune system
Number of neutrophils

Question 16

What is the key treatment of Aspergillus?

Answer 16

Voriconazole

(must be 100% sure its Aspergillus before treating with Voriconazole)

Question 17

What is infection by Mucor called?

Answer 17

Mucormycosis

Question 18

What does Mucor invade?

Answer 18

Major blood vessels (angioinvasion)

(Aspergillus does this as well, but to a less extent. Mucor is the main angioinvasive mold)

Question 19

What does Mucor angioinvasion lead to?

Answer 19

Black pus + black necrotic tissue

Question 20

What is the most common pathogen of the Mucor group? (ON EXAM)

Answer 20

Rhizopus

Question 21

What is the morphology of Mucor?

Answer 21

Filamentous mold
Large diameter, aspetate hyphae
90 degree branching

Question 22

What are the 2 things that can cause Mucor infections?

Answer 22

Inhaling spores
Spore implantation into tissue

Question 23

What patients are at high risk for Mucor infection?

Answer 23

Uncontrolled diabetes + ketoacidosis
Cancer (especially those w/ low neutrophils)

Question 24

What mucor infection can have oral manifestations such as black necrotic lesions on hard palate?

Answer 24

Rhinocerebral mucormycosis

Question 25

What is the key treatment for Mucor infection?

Answer 25

Aggressive surgical methods

Question 26

What enhances the virulence of Mucor?

Answer 26

Voriconazole (this is why its so important to make sure it is Aspergillus before treating with Voriconazole!!!)

Question 27

Where do Histo, Blasto, and Coccidio infect?

Answer 27

Respiratory tract

Question 28

T/F: Oral manifestations of Histo, Blasto, and Coccidio are very common

Answer 28

FALSE, oral manifestations are rare, but may be seen in immunocompromised

Question 29

What are the diseases caused by Histo, Blasto, and Coccidio restricted to?

Answer 29

Defined geographical areas

Question 30

Histo, Blasto, and Coccidio are all ___________ dimorphic

Answer 30

thermally

Question 31

Where are Histo, Blasto, and Coccidio seen as filamentous mold?

Answer 31

Soil

Question 32

Where are Histo, Blasto, and Coccidio seen as yeast with budding?

Answer 32

Body tissues

Question 33

Which dimorphic fungi is an exception because it does NOT form a traditional yeast, but instead forms a structure called a spherule that contains endospores?

Answer 33

Coccidio

Question 34

Habitat for Histo

Answer 34

Bird and bat droppings

Question 35

Habitat for Blasto

Answer 35

Organic matter (rotting wood, animal droppings, plants)

Question 36

Habitat for Coccidio

Answer 36

Fine sand and silt

Question 37

Transmission for Histo and Blasto

Answer 37

Inhaling spores -> becomes yeast during infection

Question 38

Transmission for Coccidio

Answer 38

Inhaling spores -> becomes spherules during infection

Question 39

Common geographical area for Histo

Answer 39

Ohio and Mississippi river valleys + Louisville

Question 40

Common geographical area for Blasto

Answer 40

Ohio, Mississippi, Missouri, and Arkansas river valleys + Louisville Minnesota and Wisconsin

Question 41

Common geographical area for Coccidio

Answer 41

Hot, arid Sonora desert region of Southwestern US Cali, Arizona, New Mexico, Texas Parts of Mexico in San Joaquin valley

Question 42

What diseases of Histo, Blasto, Coccidio contribute to the oral manifestations?

Answer 42

Disseminated diseases

Question 43

How do you diagnose Histo, Blasto, Coccidio?

Answer 43

Direct microscopy exam - 10% KOH or silver stain

Question 44

What are you looking for when diagnosing Histo, Blasto, Coccidio using direct microscopy exam?

Answer 44

Histo yeast -> narrow bud Blasto yeast -> broad based bud Coccidio spherule -> sac filled with spores

Question 45

Which yeast has a capsule?

Answer 45

Cryptococcus

Question 46

How is Cryptococcus different from traditional yeast?

Answer 46

It produces a polysaccharid capsule

Question 47

How is the most common species of Cryptococcus transmitted?

Answer 47

Inhaling yeast from exposure to pigeon droppings

Question 48

When does Cryptococcus have oral manifestations particularly in the immunocompromised?

Answer 48

Disseminated forms

Question 49

How do you diagnose Cryptococcus?

Answer 49

India ink stain (allows you to see capsule)

Question 50

Do Dermatophytes have oral manifestations?

Answer 50

NO, but it may be expressed on facial surface

Question 51

Where are Dermatophyte infections found?

Answer 51

Superficial skin, hair, nails ("tinea")

Question 52

What is the major virulence factor of Dermatophytes?

Answer 52

Keratinase

Question 53

What does keratinase degrade in Dermatophyte infections?

Answer 53

Skin, hair, nails

Question 54

What are the 3 species of Dermatophytes?

Answer 54

Trichophyton Microsporum Epidermophyton

Question 55

Trichophyton morphology

Answer 55

Cigar-shaped macroconidia Many microconidia

Question 56

Microsporum morphology

Answer 56

Rough, spindle-shaped macroconidia Some microconidia

Question 57

Epidermophyton morphology

Answer 57

Smooth, club-shaped macroconidia NO microconidia

Question 58

How are Dermatophytes transmitted?

Answer 58

Direct via contact with spores (infected tissue, soil) Indirect transmission via contaminated surfaces/objects (hairbrush, comb, carpet)

Question 59

Tinea capitis lesion location

Answer 59

Scalp (hair/skin)

Question 60

Tinea faciei lesion location

Answer 60

Non-bearded parts of face

Question 61

Tinea barbae lesion location

Answer 61

Beard, mustache, neck

Question 62

Tinea corporis (ringworm) lesion location

Answer 62

Body (trunk, arms, legs)

Question 63

Tinea manuum lesion location

Answer 63

Palms, fingers

Question 64

Tinea pedis (athletes foot) lesion location

Answer 64

Soles of feet, between toes

Question 65

Tinea unguium lesion location

Answer 65

Nails (toes more common than fingers)