Medically Important Yeasts

Question 1

o Spherical to elongate yeast-like cells or blastoconidia that reproduce by budding
o Colony pigmentation is usually absent
o Pseudohyphae (and occasionally true hyphae) may be present

Answer 1

Candida spp

Question 2

o A primary or secondary mycotic infection caused by members of the genus Candida.
o Involvement may be localized to the mouth, throat, skin, scalp, vagina, fingers, nails, bronchi, lungs, or the gastrointestinal tract, or become systemic as in septicaemia, endocarditis and meningitis.

Answer 2

Candidiasis

Question 3

Common Candida spp. Isolated from Clinical Specimens

Answer 3

C. albicans
⮚ C. parapsilosis
⮚ C. tropicalis
⮚ C. guilliermondii (Meyerozyma guillermondii) ⮚ C. pseudotropicalis
⮚ C. krusei (Pichia kudriavzevii)
⮚ C. glabrata

Question 4

Other Candida sp.

Answer 4

C. dubliniensis
⮚ C. lusitaniae (Clavispora lusitaniae)
⮚ C. kefyr (Kluyveromyces marxianus)
⮚ C. lipolytica (Yarrowia lipolytica)

Question 5

Commensal of mucous membrane and GI tract.

Answer 5

Candida albicans

Question 6

Microscopic morphology of C. albicans

Answer 6

Roundtoellipsoidalcells

Question 7

Candida albicans, germ tube negative or positive?

Answer 7

Positive

Question 8

o Germ tube positive
o Grows on media with cycloheximide
o Light green or bluish green on CHROMAgar

Answer 8

Candida albicans

Question 9

Color of Candida albicans on Chromagar

Answer 9

Light green or bluish green

Question 10

Dalmau Plate Morphology of Candida albicans

Answer 10

Presence of 1 -2 chlamydospore

Question 11

o Occasional cause of candidemia and mucosal infection

Answer 11

Candida dubliniensis

Question 12

Candida dubliniensis is Resistant to

Answer 12

fluconazole

Question 13

Microscopic morphology of Candida dubliniensis

Answer 13

o Round to ellipsoidal cells

Question 14

o Germ tube positive
o Grows on media with
cycloheximide
o Dark green color on CHROMAgar

Answer 14

Candida dubliniensis

Question 15

Color of Candida dubliniensis on Chromagar

Answer 15

Dark green color

Question 16

Dalmau Plate Morphology of Candida dubliniensis

Answer 16

Multiple in cluster chlamydospores

Question 17

Major cause of septicemia and disseminated candidiasis.

Answer 17

Candida tropicalis

Question 18

o Germ tube negative
o Grows on media with cycloheximide o Grows at 40 C
o Produces blue color on CHROMAgar

Answer 18

Candida tropicalis

Question 19

Color of Candida tropicalis on chromagar

Answer 19

Blue

Question 20

Dalmau Plate Morphology of Candida tropicalis

Answer 20

Presence of blastoconidia in single or double

Question 21

Also known as Issatchenkia orientalis or Pichia kudriavzevii

Answer 21

Candida krusei

Question 22

Candida krusei Intrinsic resistance to

Answer 22

fluconazole

Question 23

Color of Candida krusei on CHROMAgar

Answer 23

Color pink

Question 24

Dalmau Plate Morphology of Candida krusei

Answer 24

Abundant long wavy, cross matchstick appearance

Question 25

o Recently now known as Nakaseomyces glabrata o Causes urinary tract and blood infections

Answer 25

Candida glabrata

Question 26

Candida glabrata Emerging resistance to

Answer 26

amphotericin B and fluconazole

Question 27

Color of Candida glabrata on chromagar

Answer 27

Variable pigment

Question 28

Dalmau Plate Morphology of Candida glabrata

Answer 28

No pseudohyphae, budding yeast only

Question 29

Dalmau Plate Morphology of Candida parapsilosis

Answer 29

Abundant match-branch deer antler appearance

Question 30

Formerly known as C. pseudotropicalis. Revised name is Kluyveromyces marxianus

Answer 30

Candida kefyr

Question 31

Dalmau Plate Morphology of Candida kefyr

Answer 31

Logs in the side

Question 32

Now known as Clavispora lusitaniae Candida lusitaniae

Answer 32

Candida lusitaniae

Question 33

Candida lusitaniae o Dalmau Plate Morphology:

Answer 33

Slender branch pseudohyphae or bushy short chain of blastoconidia

Question 34

Now named as Yarrowia lipolytica

Answer 34

Candida lipolytica

Question 35

Urease positive

Answer 35

Candida lipolytica

Question 36

Candida lipolytica Macroscopic morphology

Answer 36

Lacy colonies that grow rapidly at 25C

Question 37

Candda lipolytica dalmau plate method

Answer 37

No blastoconidia long pseudohyphae

Question 38

o Revised nameis Meyerozyma guilliermondii o Commonly seen on cutaneous infections.

Answer 38

Candida guilliermondiii

Question 39

Candida guilliermondiii Macroscopic morphology

Answer 39

Forms cream-colored colonies at 25C

Question 40

is an emerging multidrug-resistant yeast that causes invasive infections that was first described in 2009 in Japan and has since been reported from several countries (Lockhart et al. CID 2017; 64:134-140).

Answer 40

Candida auris

Question 41

is an emerging multidrug-resistant yeast that causes invasive infections that was first described in 2009 in Japan and has since been reported from several countries (Lockhart et al. CID 2017; 64:134-140).

Answer 41

Candida auris

Question 42

How to identify C. auris ?

Answer 42

• MALDI-TOF Bruker type FDA-approved CA system database and VITEK (MALDI- TOF) MS RUO (with Saramis Ver 4.14 database and Saccharomycetaceae update). • Molecular methods

Question 43

Fungal infection of the hair shaft with white, yellowish, beige or green nodules

Answer 43

WHITE PIEDRA

Question 44

WHITE PIEDRA Etiologic agent

Answer 44

Trichosporon spp.

Question 45

Clinically significant Trichosporon spp

Answer 45

⮚ Trichosporon asahii ⮚ Trichosporon mucoides ⮚ Trichosporon inkin ⮚ Trichosporon cutaneum ⮚ Trichosporon ovoides ⮚ Trichosporon asteroides

Question 46

LABORATORY DIAGNOSIS Trichosporon spp.

Answer 46

-Direct Microscopy KOH Arthrospores -Primary isolation medium Sabouraud’s dextrose agar White or yellowish to deep cream colored

Question 47

Barrel shape arthroconidia

Answer 47

Trichosporon spp

Question 48

⮚ India ink (+) ⮚ Urease (+) ⮚ Canavanine Glycine Bromthymol Blue (CGB) Agar (-)

Answer 48

Cryptococcus neoformans

Question 49

Cryptococcus neoformans Resistant to

Answer 49

echinocandins

Question 50

⮚ India ink (+) ⮚ Urease (+) ⮚ Canavanine Glycine Bromthymol Blue (CGB) Agar (+) ⮚ Resistant to echinocandins

Answer 50

Cryptococcus gattii

Question 51

⮚ R. mucilaginosa and R. glutinis ⮚ coral red to salmon on SDA ⮚ Urease (+) ⮚ Resistant to echinocandins and fluconazole

Answer 51

Rhodotorula spp.

Question 52

Look identical to candida used for fermentation yeast used or probiotics

Answer 52

Saccharomyces cerevisiae