Medically important yeast

Question 1

Yeasts produce asexually by ______

Answer 1

Budding (blastoconidia formation)

Question 2

Yeasts produce sexually by _____

Answer 2

ascopores / basidiospores

Question 3

An outpouching of cell wall that becomes tubular and with no constriction

Answer 3

Germ tube

Question 4

Elongate, resemble links of sausage and with cell wall constrictions

Answer 4

Pseudohyphae

Question 5

Best way to identify yeast

Answer 5

Matrix-assisted laser desorption ionization time of flight mass spectrometry (MALDI-TOF MS)

Question 6

Most commonly encountered opportunistic fungi

Answer 6

Candida spp.

Question 7

Candida spp. may be recovered from?

Answer 7

Oropharynx
GI tract
Genitourinary tract
Skin

Question 8

It is considered part of the normal oropharyngeal microbiota

Answer 8

Candida spp.

Question 9

Candida infection that surrounds the toe/finger nail

Answer 9

Paronychia

Question 10

Fungal infection of nail and nail bed

Answer 10

Onychomycosis

Question 11

Candida infection in the area where two skin touch/rub

Answer 11

Intertriginous candidiasis

Question 12

Yeast in blood

Answer 12

Fungemia / Candidemia

Question 13

Non-albicans candida that is more common in adults

Answer 13

C. glabrata

Question 14

Common in patients w/ hematologic malignancies

Answer 14

C. tropicalis

Question 15

Primary cause of fungemia and the 2nd most common Candida isolate

Answer 15

C. parapsilosis

Question 16

(True or False): Candida spp. are strongly gram negative

Answer 16

False (positive)

Question 17

Colonies appear starlike or possess feet-like projections

Answer 17

C. albicans

Question 18

C. glabrata ferments and assimilates ______ & ______

Answer 18

Glucose & Trehalose

Question 19

C. tropicalis ferments and assimilates _____ & _____

Answer 19

Sucrose & Maltose

Question 20

It is well recognized in patients w/ AIDS

Answer 20

Cryptococcal Meningitis

Question 21

The capsule that helps C. neoformans survive passage thru pigeon gut

Answer 21

Polysaccharide capsule

Question 22

(True or False): The degree of infection depends on the variant from the yeast

Answer 22

False (depends on host immune status)

Question 23

It acts as a virulence factor by making the organism resistant to leukocyte attack

Answer 23

Phenoloxidase

Question 24

The most widely used method for the rapid detection of C. neoformans

Answer 24

India ink preparation

Question 25

6 medically important yeasts

Answer 25

``` Candida spp. Cryptococcus spp. Malassezia sp. Rhodotorula spp. Saccharomyces cerevisiae Trichosporon spp. ```

Question 26

How many days does C. neoformans appear on culture media?

Answer 26

1-5 days

Question 27

C. neoformans appears what color on niger seed agar

Answer 27

Brown

Question 28

C. neoformans appears what color on inhibitory mold agar

Answer 28

Golden yellow

Question 29

A skin infection characterized by superficial, brownish scaly areas

Answer 29

Tinea versicolor

Question 30

It causes tinea versicolor

Answer 30

Malassezia furfur

Question 31

The morphology of M. furfur is commonly described as?

Answer 31

Spaghetti and meatballs

Question 32

It is recognized as oval or bottle-shaped cells that exhibit monopolar budding

Answer 32

Malassezia furfur

Question 33

Agar medium for the cultivation of Malassezia furfur is overlaid with a long fatty chain acid or ____

Answer 33

Olive oil

Question 34

A normal resident microbiota of human skin

Answer 34

Rhodotorula spp.

Question 35

Rhodotorula spp. resembles what opportunistic fungi

Answer 35

Cryptococcus spp.

Question 36

Typically recovered from moist environmental sources

Answer 36

Rhodotorula spp.

Question 37

Color of Rhodotorula spp. colonies on SDA

Answer 37

Orange/red

Question 38

Common yeast used in baking and a variety of food products

Answer 38

Saccharomyces cerevisiae

Question 39

Trichosporon organisms are recovered occasionally from?

Answer 39

Respiratory tract secretion Skin Oropharynx Stool

Question 40

It is characterized by soft, yellow or pale brown aggregations around hair shafts

Answer 40

White piedra

Question 41

It causes white piedra

Answer 41

Trichosporon spp.

Question 42

It is the most commonly accepted and economical method used to identify yeast

Answer 42

Germ tube test

Question 43

Pseudohyphae / hyphae is rarely seen on what yeast?

Answer 43

Cryptococcus spp.

Question 44

A Chlamydoconidia is present on the hyphae of what yeast?

Answer 44

Candida albicans

Question 45

A Rudimentary hyphae is sometimes present on what yeast?

Answer 45

Saccharomyces spp.

Question 46

(True or False): 1-5 days of incubation is required for Rapid urease test

Answer 46

False (1-2 days)

Question 47

Useful in screening urease producing yeast

Answer 47

Rapid urease test

Question 48

Used as presumptive identification of C. glabrata

Answer 48

Rapid trehalose test

Question 49

Used a presumptive identification of C. neoformans

Answer 49

Rapid selective urease test

Question 50

3 methods used before final identification of C. neoformans

Answer 50

Cornmeal agar morphology Carbohydrate utilization Phenoloxidase detection (using Niger seed agar)

Question 51

(True or False): C. neoformans readily produce phenoloxidase

Answer 51

True

Question 52

Most common used conventional method for definitive identification of yeasts

Answer 52

Carbohydrate utilization