Fungal Infections

Question 1

What is fungal cell membrane made of?

Answer 1

Ergosterol

Question 2

What are the two morphological forms of fungi?

Answer 2

Unicellular - yeasts; Multicellular filamentous - mold

Question 3

What are the two forms in which fungi are found?

Answer 3

Normal human flora - yeasts; Environment - Molds

Question 4

What is the primary mechanisms for containing fungal infections?

Answer 4

Neutrophil phagocytosis

Question 5

What is mycoses/.

Answer 5

Fungal infection

Question 6

What are the two types of mycoses?

Answer 6

1. Endemic infection - caused by geographically confined true pathogens;
2. Opportunistic infection - caused by fungi that are not true pathogens

Question 7

What is acute disseminated histoplasmosis?

Answer 7

Usually occurs in immunocompromised patients

Question 8

What is chronic disseminated histoplasmosis?

Answer 8

Observed in older adults with no obvious immune deficiency

Question 9

What are the symptoms of Blastomyces?

Answer 9

causes pneumonia. Skin lesions develop as a result of hematogenous dissemination

Question 10

What important structures do Coccidiodes form?

Answer 10

Spherules that contain hundreds of endospores. (Dimorphism is NOT temperature dependent)

Question 11

What is the most frequent opportunistic fungal pathogen?

Answer 11

Candida albicans

Question 12

What is Thrush?

Answer 12

Thick, white lesions of the oropharyngeal and vaginal mucosa

Question 13

What is intertriginous candidiasis?

Answer 13

Proliferation in warm, moist areas of skin (diaper rash)

Question 14

What does cryptococcus neoformans form?

Answer 14

A CAPSULE in tissues, but not in the environment. Results in meningitis.

Question 15

What does candida end up affecting?

Answer 15

The liver

Question 16

What does melanin do?

Answer 16

Increases strength of cell wall increasing resistance to enzyme degradation and free radicals

Question 17

What are the two types of Major pathogenic species of Aspergillus and what is special about them?

Answer 17

A. fumigatus and A. flavus. They DO NOT GROUW IN NORMAL TISSUE (must invade profoundly immunocompromised patients)

Question 18

What is “angioinvasive”

Answer 18

Hyphae invade through blood vessel walls causing tissue infarction, hemorrhage, and necrosis.

Question 19

Mucormycoses are similar to Aspergillus in what respect?

Answer 19

Both are angioinvasive

Question 20

What are the two forms of Mucormycoses?

Answer 20

Rhinocerebral form - unique to diabetics; Disseminated zygomycosis - lesions of pulmonary system

Question 21

What is special about pneumocystis?

Answer 21

1. Has never been grown in vitro.

2. Was the sentinel infection in AIDS, malnourished children, and immunocompromised individuals

Question 22

What is the most common fungal infection in humans?

Answer 22

Dermatophyte

Question 23

What is the most common pathogenic fungal infection in humans?

Answer 23

Candidia

Question 24

What are the three etiological genera associated with dermatophyte skin infections?

Answer 24

Microsporum, trichophyton, epidermophyton

Question 25

How do dermatophytes enter the skin?

Answer 25

Must have some sort of skin trauma (continuous moist conditions)

Question 26

What type of Mycoses result in infections caused by fungal pathogens that are geographically restricted?

Answer 26

Endemic Mycoses

Question 27

What type of Mycoses causes systemic infections only in immunocompromised patients?

Answer 27

Opportunistic mycoses

Question 28

What type of mycoses result in infections caused by fungi that are not true pathogens?

Answer 28

Opportunistic mycoses

Question 29

What type of mycoses are considered "true pathogens" that typically result in systemic infections in healthy individuals?

Answer 29

Endemic infections

Question 30

Describe how Polyenes (amphotericin B) are effective in treating coccidodiomycosis

Answer 30

Polyenes bind to the cell wall ergosterol of the coccidodio- and form channels

Question 31

Describe why Azoles (itraconazole) is effective in treating coccidiodiomycosis

Answer 31

Azoles interfere with the ergosterol synthesis in the coccidodio-

Question 32

What is the most frequent opportunistic fungal pathogen?

Answer 32

Candida albicans

Question 33

How/when does Candida albicans cause disease in humans?

Answer 33

Usually endogenous to humans, therefore only causes disease if the normal flora is disrupted

Question 34

What is different about infection by candida albicans (what kind of exception is it?)

Answer 34

Dimorphism exception - Mycelial form (not yeast form) causes disease in humans.

Question 35

Where is cryptococcus neoformans found?

Answer 35

It is yeast found in soil (best at 37 degrees) that is contaminated with bird (pigeon) excreta

Question 36

Describe what is important about the capsule associated with cryptococcus neoformans

Answer 36

Large polysaccharide capsule that is in the tissue, but not in the environment (only makes when needed due to body temp)

Question 37

What fungal outbreak is commonly associate with construction, demolition, or renovation activities in or near hospital wards accomodating immunocompromised patients?

Answer 37

Nosocomial outbreaks of invasive aspergillosis

Question 38

What 3 conditions are required for growth of fungal infections on humans?

Answer 38

1. Trauma 2. Wetness 3. Warmth