Hyaline Opportunists

Question 0

What is the name for aseptate, hyaline fungi?

Answer 0

Mucorales, formerly Zygomycetes

Question 1

Do healthy people get opportunistic infections?

Answer 1

NO

Question 2

What 4 organisms are agents of mucormycoses?

Answer 2

Rhizopus, Mucor, Rhizomucor, and Lichtheimia (formerly Absidia)

Question 3

What is the most common agent of mucormycoses and is difficult to treat?

Answer 3

Rhizopus

Question 4

Where is Mucorales commonly found?

Answer 4

in nature, soil

Question 5

How is Mucorales commonly obtained by the body?

Answer 5

inhalation

Question 6

In what case are you more likely to develop Mucorales?

Answer 6

Type I Diabetics (poorly controlled or in ketoacidosis)

Question 7

What is the most common clinical presentation of Mucorales?

Answer 7

Rhinocerebral; nasal sinus infection that spreads to orbits or the brain

Question 8

What is the second most common clinical presentation of Mucorales?

Answer 8

pulmonary and systemic infections (especially in Bone Marrow transplant patients)

Question 9

What is commonly seen in direct examination of Mucorales aspiration or biopsy?

Answer 9

Necrotic or dead tissue, aseptate hyphae with 90* branching and broad ribbon like shape

Question 10

What do Mucorales look like on culture plates?

Answer 10

rapid, profuse growth (lid lifters); aseptate hyphae; sporangium, sac-like structures containing conidia; may have rhizoids or root-like structures

Question 11

Does Mucor have rhizoids?

Answer 11

NO

Question 12

What is the most common Mucorales causing disease?

Answer 12

Rhizopus

Question 13

Does Rhizopus have rhizoids?

Answer 13

YES, distinct rhizoids at the base of the sporangiophore; sporangia can also collapse creating umbrelllas

Question 14

This Mucorales has delicate rhizoids at points between the sporangiophores (intermodal).

Answer 14

Lichtheimia (Absidia)

Question 15

Where is septate, hyaline fungi often found?

Answer 15

granulocytopenia (neutropenia)

Question 16

What is the most commonly found organism in patients with neutropenia?

Answer 16

Aspergillus

Question 17

Aspergillus found as an overgrowth in an old cavity in the lung is called what? It does not grow in living tissue (not invasive)

Answer 17

Fungus Ball

Question 18

What is the single most predictive factor of aspergillosis with a very high mortality (even with treatment)?

Answer 18

Neutropenia

Question 19

What can cause neutropenia?

Answer 19

cancer (leukemia), transplant

Question 20

When looking at a sputum or tissue biopsy, what do Aspergillus look like?

Answer 20

septate hyphae with parallel sides which usually branch at acute 45* angels and may invade into blood vessels.

Question 21

What enzyme does Aspergillus produce?

Answer 21

elastase

Question 22

Where does vascular invasion of Aspergillus take place and what causes death?

Answer 22

Especially in the lung and death due to loss of blood supply.

Question 23

What is the most common species of Aspergillus?

Answer 23

Aspergillus fumigatus (followed by A. flavus, A. niger, and A. terreus)

Question 24

What color does Aspergillus fumigatus appear?

Answer 24

blue-gray/blue-greenish colonies

Question 25

Describe the microscopic characteristics of A. fumigatus.

Answer 25

conidia cover only half of the vesicle (looks like hair standing straight up)

Question 26

Describe plate colony color of Aspergillus flavus.

Answer 26

Yellow/brown colonies

Question 27

Describe the microscopic view of A. flavus.

Answer 27

conidia cover most of the vesicle and have rough (spiny) conidiophores (spiny dots)

Question 28

What does a plate colony of Aspergillus terreus look like?

Answer 28

Cinnamon colored colonies

Question 29

Describe the microscopic view of A. terreus.

Answer 29

cover upper half of the vesicle and usually fan outward (do not have spiny dots)

Question 30

Describe the plate color appearance of Aspergillus niger.

Answer 30

colonies are black dots on white (peppered)

Question 31

Describe the colony appearance of A. niger.

Answer 31

black color, phialides cover the entire vesicle

Question 32

These colonies appear greenish or yelow on plates and have a brush like appearance with NO vesicle (look like fingerlike projections)

Answer 32

Penicillium

Question 33

This organism appears as long, tapered phialides, with oval conidia; very delicate.

Answer 33

Paecilomyces

Question 34

This organism appears as a long string of light bulb conidia.

Answer 34

Scopulariopsis

Question 35

These appear as oval conidia that group up in clusters.

Answer 35

Acremonium

Question 36

This organism appears as spiny/rough macroconidia and resemble Histoplasma capsulatum but are not pathogenic (can also appear as cigar-shaped microconidia).

Answer 36

Sepedonium

Question 37

These organisms appear as single conidia on ends or conidiophores, look like lollipops.

Answer 37

Pseudallescheria boydii and Scedosporium boydii

Question 38

This organism is a plant pathogen, found in grains, hospitals, and potted plants.

Answer 38

Fusarium

Question 39

In what two medical conditions is Fusarium found?

Answer 39

Transplant patients (100% mortality) and keratitis (contact lens' and solution)

Question 40

What is the typical microscopic appearance of Fusarium?

Answer 40

sickle or canoe shaped

Question 41

Describe the mortality rate in disseminated aspergillosis in immunocompromised patients.

Answer 41

Breaks apart fungus ball and has a very high mortality