Intro to Fungi - Ryan

Question 1

Are fungi prokaryotic or eukaryotic?

Answer 1

eukaryotic

Question 2

What are Conidia?

Answer 2

asexual reproductive elements of fungi

Question 3

What are spores?

Answer 3

sexual reproductive elements of fungi

Question 4

What are superficial infections?

Answer 4

fungal infections just on outer surface of skin. Can be removed by simple soap and scrubbing. cause discolorations. Often from poor hygeine

Question 5

What are cutaneous infections?

Answer 5

ringworm, athlete’s foot, etc. Infections of the skin that can.

Question 6

What are subcutaneous infections?

Answer 6

OFten from wound to the skin. Can involve lymphatics

Question 7

What are systemic infections?

Answer 7

can cause infections in a immuno-competent person. Usually from inhalation. Most infectious and tend to be most severe. Can cause chronic infections resembling tuberculosis.

Question 8

What are opportunistic infections?

Answer 8

Attack when the patient is immunocompromised and often have the highest mortality rates (not because they are themselves so infectious, but because the patients immune system can’t retaliate).
Severe infections that do not respond to antibiotics

Question 9

How do fungi differ from animal cells?

Answer 9

1. fungi contain a rigid cell wall containing chitin that can be visualized after 10% KOH treatment
2. instead of cholesterol, fungal membranes contain ergosterol which is a target for several anti-fungal drugs

Question 10

What is ergosterol?

Answer 10

a structural component of fungal membranes. often a target of anti-fungal drugs

Question 11

What are yeasts?

Answer 11

single cell fungi

Question 12

What are molds?

Answer 12

multi-cellular fungi

Question 13

How are fungal infections diagnosed?

Answer 13

clinical appearance, take biopsy and treat with 10% KOH to dissolve all except fungal cell walls then look in microscope, look for hyphe, or culture

Question 14

What extra measures must be taken when culturing fungi?

Answer 14

Sabourdaud’s medium. High glucose and low pH medium. This inhibits bacterial growth and allows fungal growth, which grow very slowly. Can also use antibiotics

Question 15

What are hyphae?

Answer 15

tube-like extensions developed by molds

Question 16

Are there more antibacterials or antifungals?

Answer 16

far more antibacterials than antifungals

Question 17

Why are fungal infections very hard to completely eradicate?

Answer 17

fungi grow very slowly and a lot of times they infect stable structures such as nailbeds

Question 18

What are the three major targets of anti-fungals?

Answer 18

1. cell membrane ergosterol or related proteins
2. cell wall
3. genome replication

Question 19

What is a mycelium?

Answer 19

intertwined mass of hyphae

Question 20

What are dipmorphic fungi?

Answer 20

fungi that have the ability to switch between yeast and mold.

Question 21

Under what conditions would you expect a dimorophic fungi to form yeast?

Answer 21

in tissues and at temperatures at 37C in culture

Question 22

Under what conditions would you expect dimporphic fungi to form molds?

Answer 22

in culture at room temperatures

Question 23

What are disseminated fungal infections usually treated with?

Answer 23

amphotericin B and/or azoles

Question 24

What are the three problems fungi generally cause?

Answer 24

1. allergies
2. mycotoxicoses (eg, mushroom poisoning)
3. mycoses (true infections)

Question 25

What is Tinea Capitis?

Answer 25

Tinea = ringworm
Capitis = scalp

Question 26

What are the four phyla of human fungal pathogens?

Answer 26

1. zygomycetes
2. ascomycetes
3. basidiomycetes
4. deuteromycetes (fungi imperfecta)
   a. lacks a sexual stage

Question 27

What is Sporotrichosis?

Answer 27

caused by sprothrix schenckii (dimorphic fungus). Found on plants and leaves. Grows particularly well on roses. Two forms of it: fixed form and lymphocutaneous form. Lymphocutaneous form is more dangerous because it will spread through lymph.

Question 28

How is sporotrichosis diagnosed?

Answer 28

look for rosette-shaped conidia

Question 29

What is histoplasmosis?

Answer 29

systemic fungal infection that usually starts out as pulmonary infection that is inhaled. Almost 80% of memphis residents have been infected by it.

Question 30

What cell type is very effective against opportunistic fungi?

Answer 30

neutrophils.

T cells are also of primary importance

Question 31

What is candidiasis?

Answer 31

yeast infections. They are really overgrowths because they are almsot always present.

Question 32

What is thrush?

Answer 32

oral yeast infection of candidiasis.