Intro to Mycology

Question 0

What composes the cell wall of bacteria?

Answer 0

peptidoglycan

Question 1

What composes the cell wall of fungi?

Answer 1

Glucan and chitin (glucosamine), and ergosterol

Question 2

What makes treatment difficult for fungi?

Answer 2

they resemble human cells, eukaryotes

Question 3

What is a single cell yeast?

Answer 3

conidium (conidia)

Question 4

What is a bud from asexual reproduction?

Answer 4

blastoconidia

Question 5

What are products of sexual reproduction (less common)?

Answer 5

ascospores

Question 6

These form from elongation of blastoconidia (constrictions).

Answer 6

pseudohyphae

Question 7

These are the beginning of true hyphae (no constrictions) .

Answer 7

germ tubes

Question 8

If molds look fuzzy or wooly macroscopically and have entertwined hyphae this is also known as what?

Answer 8

Mass of mycelia

Question 9

These are crosswalls that are present in hyphae.

Answer 9

septate

Question 10

This means crosswalls are absent (or sparse), aka coenocytic

Answer 10

aseptate

Question 11

This means hyphae growth within the surface of the medium (agar).

Answer 11

vegetative

Question 12

These hyphae filaments extend above the agar surface (on top).

Answer 12

aerial

Question 13

These hyphae are nonpigmented or slightly pigmented.

Answer 13

hyaline

Question 14

These hyphae are dark or black (melanin) on the reverse side of the colony.

Answer 14

dematiaceous

Question 15

These hyphae break or fragment; look like floating logs in a river

Answer 15

Arthroconidia

Question 16

These are round and thick-walled conidia that form directly within or at the ends of hyphae; example includes Candida albicans

Answer 16

chlamydoconidia

Question 17

This is a specialized part of the hyphal filament that gives rise to conidia.

Answer 17

conidiophore

Question 18

What stains hair, skin, and nails and also breaks down keratin leaving an outline of the hyphae?

Answer 18

KOH

Question 19

What stains patient specimens, chitin, using a fluorescent dye?

Answer 19

Calcofluor White

Question 20

What stains the capsule of Cryptococcus in patient specimens?

Answer 20

India Ink

Question 21

In this patient specimen stain, yeast stains blue.

Answer 21

Giemsa stain

Question 22

All yeasts and hyphae turn brown-black with this patient specimen stain.

Answer 22

GMS (Gomori’s Methenamine Silver)

Question 23

What is the best way to culture blood and bone marrow?

Answer 23

Isolator (lysis centrifugation)

Question 24

What is the best way to culture hair, skin, and nails (dermatophyte infections)?

Answer 24

scrape outer edge of skin lesion and use 10-20% KOH

Question 25

What two types of fungal isolation media do we use most commonly?

Answer 25

sabouraud dextrose agar (SDA or SAB) and potato dextrose (PDA) or Potato Flake (PFA)

Question 26

What are the incubation requirements for molds and yeast?

Answer 26

mold: 22-25'C yeast: 37'C

Question 27

Describe what molds look like macroscopically?

Answer 27

fluffy and fuzzy (aerial mycelia)

Question 28

Describe what yeast looks like macroscopically?

Answer 28

usually creamy (sometimes dry)

Question 29

What is the best method to view molds?

Answer 29

slide cultures with LPCB (lactophenol cotton blue)

Question 30

why do we see more recent cases of mycoses?

Answer 30

the host has changed, not the fungi

Question 31

How do people get mycoses?

Answer 31

inhalation of mold condida most common way of mold infections

Question 32

Describe fungal treatment, including common azole.

Answer 32

many agents are toxic to patients because cell wall structure so similar; common cause of renal toxicity= Amphotericin B

Question 33

What is the most common antimicrobial susceptibility test of fungi?

Answer 33

broth dilution (standard method)

Question 34

Most yeast like fungi stain gram ______.

Answer 34

Positive

Question 35

Why do we use a class II safety hood when handling these organisms?

Answer 35

airborne conidia can cause infections with inhalation

Question 36

What is CSAB (SAB with antimicrobials) used in lab?

Answer 36

Cyclohexamide inhibits bacteria and environmental fungi

Question 37

What agar is used to examine yeast phase of dimorphics?

Answer 37

BHI with blood

Question 38

What two other methods, besides slide culture, can you use to observe molds microscopically?

Answer 38

Tease mount in LPCB and cellophane tape preparation with LPCB