Intro to Clinical Mycology

Question 1

What are three ways fungi can affect humans?

Answer 1

1) allergens
2) toxin producers (mycotoxins)
3) infectious agents (colonization)

Question 2

What are saprophytes?

Answer 2

fungi that live on dead or decaying matter

Question 3

Can fungi live symbiotically with humans (beneficial for both)?

Answer 3

yes

Question 4

Is colonization required for allergens to infect humans?

Answer 4

no

Question 5

What are peanuts constantly tested for?

Answer 5

aflatoxin that is toxic to humans

Question 6

What are two important differences between fungal and human cells?

Answer 6

1) cell wall

2) membrane sterol composition

Question 7

What sterol composition do fungal cell membrane have?

Answer 7

ergosterol

Question 8

Why is it important to target fungal cell walls?

Answer 8

human cells do not have cell walls

Question 9

What’s the function of fungal cell wall (4)?

Answer 9

1) shape
2) rigidity
3) strength
4) protection from osmotic shock

Question 10

About 90% of a fungal cell mass is…

Answer 10

cell wall

Question 11

What are the two fungal structures and classification?

Answer 11

1) yeast

2) mold

Question 12

Is yeast unicellular or multicellular?

Answer 12

unicellular

Question 13

Some fungi can grow as both yeast and molds, what is this called?

Answer 13

dimorphic

Question 14

By what process do yeast reproduce in?

Answer 14

budding

Question 15

What shape do yeast have?

Answer 15

spherical or ellipsoid shape

Question 16

Fungal cell wall is primarily composed of all of the following polysaccharides except:

1) chitin
2) cellulose
3) chitosan
4) mannan
5) galactomannan

Answer 16

galactomannan

Question 17

Molds grow through the development of ____

Answer 17

hyphae

Question 18

What shapes do hyphae have?/

Answer 18

tube or ribbon shaped

Question 19

Hyphae of most fungi have cross-walls which divide into segments called ____

Answer 19

septa

Question 20

Under proper conditions some yeast form structures known as ____

Answer 20

pseudohyphae

Question 21

Candida albicans (yeast) produces a structure known as a ____

Answer 21

germ tube

Question 22

A mass of intertwined hyphae is called ____

Answer 22

mycelium

Question 23

How do molds reproduce?

Answer 23

sexually or asexually

Question 24

What type of mold reproduction produces conidia?

Answer 24

asexual

Question 25

What type of mold reproduction produces spores?

Answer 25

sexual

Question 26

Will you be able to tell the difference between bacteria and yeast macroscopically on an agar?

Answer 26

No, but definitely microscopically

Question 27

What are the different types of fungal infections?

Answer 27

1) superficial mycoses 2) cutaneous mycoses 3) subcutaneous mycoses 4) systemic mycoses 5) opportunistic mycoses

Question 28

Which type of fungal infection involves outermost layers of skin and hair?

Answer 28

superficial mycoses

Question 29

Which type of fungal infection extends deep into the epidermis as well as invasive hair and nail infections?

Answer 29

cutaneous mycoses

Question 30

Which type of fungal infections involve the dermis, subcutaneous tissues, muscle and fascia?

Answer 30

subcutaneous mycoses

Question 31

Which type of fungal infections originate primarily in the lung but may spread to any organ in the body?

Answer 31

systemic mycoses

Question 32

Which type of fungal infections associate primarily with immunosuppressed individuals?

Answer 32

opportunistic myscoses

Question 33

Which immunity in healthy individuals is generally sufficient in preventing fungal infections?

Answer 33

innate

Question 34

What are some things that innate immunity can provide in preventing fungal infections?

Answer 34

1) intact skin 2) pH 3) competition with normal bacterial flora 4) epithelial turnover rate 5) desiccated nature of the stratum corneum 6) mucous membranes - antimicrobial peptides, ciliated cells

Question 35

What's another way fungi can gain access to host tissues?

Answer 35

traumatic implantation or inhalation

Question 36

Does adaptive immunity play a role in controlling and eliminating fungal infections?

Answer 36

cell mediated immunity is essential and most evidence supports that humoral immunity provides little support

Question 37

The severity of fungal disease depends on what factors?

Answer 37

1) size of inoculum 2) magnitude of tissue destruction 3) ability of fungi to multiply in tissues 4) immunologic status of host

Question 38

What are two types of therapy for antifungal drugs?

Answer 38

1) topical | 2) systemic

Question 39

Topical therapy is used to treat which type of fungal infections?

Answer 39

superficial and most cutaneous

Question 40

Systemic therapy is used to treat which type of fungal infections?

Answer 40

subcutaneous and systemic infections and some cutaneous as well

Question 41

The antifungal agents Azole, Allylamines, Thiocarbamates and Morpholines all target what in fungi?

Answer 41

inhibiting the synthesis of ergosterol

Question 42

What specific polyene binds to ergosterol in fungal membranes?

Answer 42

Amphotericin B

Question 43

How does Amphotericin B work?

Answer 43

disrupts fungal membrane by forming channels that lead to osmotic lysis

Question 44

Echinocandins are what type of antifungal drugs?

Answer 44

inhibitors of beta-glucan synthesis

Question 45

Echinocandins is mostly used to treat which fungal diseases?

Answer 45

Candida and Aspergillus

Question 46

How are fungal infections frequently diagnosed?

Answer 46

direct visualization of fungal elements in infected tissues

Question 47

Following cultivation, what are some ways to identify fungi?

Answer 47

colony morphology | hyphal and spore structures

Question 48

Briefly describe how KOH prep work

Answer 48

KOH dissolves the skin, nail, or whatever human specimen and the leftover is fungi (human cells dissolves at a much greater rate than chitinous cell walls found in fungi)

Question 49

Do fungi stain Gram (+) or (-)?

Answer 49

ALL fungi stain Gram (+)!!

Question 50

What fungal organism should come to mind upon the mention of India Ink stain? Why?

Answer 50

Cryptococcus neoformans | It is a specific stain for their capsules!!

Question 51

Germ tube test?

Answer 51

Candida albicans

Question 52

How long does it take to culture fungi routinely?

Answer 52

3-4 weeks (very slowwww)