MYCO & VIROLOGY L4 (Midterms- Yeast)

Question 1

Incidence of Yeast infection has escalated due to the increasing?

Answer 1

Immunosuppression among patients

Question 2

TRUE OR FALSE: Cutaneous infections may be extremely aggressive and difficult to treat

Answer 2

**FALSE. Should be Yeast infection

Question 3

Coined term for those not capable of sexual reproduction

Answer 3

Yeast-like

Question 4

Able to reproduce sexually

Answer 4

Yeast

Question 4

Often part of microbiota

Answer 4

Agents Yeast Infection

Question 5

Generally, yeast reproduce asexually which is through the ____________ but they can also reproduce sexually through ___________

Answer 5

blastoconidia; ascospores and basidiospores

Question 6

Enumerate at least three general characteristics of a Yeast

Answer 6

• Eukaryotic
• Unicellular organism
• Round to oval
• Size: 2-60 um
• Reproduce asexually by budding (blastoconidia)

Question 7

Enumerate the characteristics for differentiation of yeasts

Answer 7

• Cell size
• Presence and absence of capsule
• Budding base (broad, narrow)

Question 8

TRUE OR FALSE: Differentiation of yeasts in direct microscopic and histopathologic examination of clinical specimen is often impossible.

Answer 8

TRUE

Question 9

An outpouching of the cell wall that becomes tubular and does not have a constriction at its base

Answer 9

Germ Tube

Question 9

Buds elongate, fail to dissociate, and form subsequent buds; resemble links of sausage

Answer 9

Pseudohyphae

Question 10

Have cell wall constrictions rather than true intracellular septation delineating the fungal cell border

Answer 10

Pseudohyphae

Question 11

It represents the initial stage of true hyphae formation

Answer 11

Germ Tube

Question 12

Macroscopically, it appears moist, creamy, may have bright pigments, and is either hyaline/melanized

Answer 12

Yeasts

Question 13

Yeasts may produce a capsule resulting in a ______ or ________ colonial appearance

Answer 13

shiny; mucoid

Question 14

Responsible for the most commonly encountered opportunistic fungal infections

Answer 14

Candida spp.

Question 15

Fourth most common cause of hospital acquired bloodstream infections (BSI)

Answer 15

Candida spp.

Question 16

Mortality rate of Candida spp. is as high as?

Answer 16

50%

Question 17

The most commonly isolated yeast

Answer 17

C. albicans

Question 18

An infection of the mucous membranes in the mouth, is considered a localized infection

Answer 18

Thrush (caused by Candida spp.)

Question 19

Thrush can be seen in?

Answer 19

newborns and patients with HIV

Question 20

These are once believed to not cause a disease

Answer 20

Non-Albicans Candida

Question 21

Common urinary isolate, resistant to antifungal drugs, infections include endocarditis and meningitis, and is higher in older adults than in young adults and children

Answer 21

C. glabrata

Question 22

C. glabrata can be differentiated from C. albicans through?

Answer 22

sugar (trehalose) assimilation

Question 23

Seen in **neonates** and the **second common cause of positive blood culture**

Answer 23

C. parapsilosis

Question 24

This organism is **positive (+)** for **Germ tube**

Answer 24

C. albicans

Question 25

***Microscopically***, it reveals **budding yeast cells**, **2-4 um** in diamater

Answer 25

Non-Albicans Candida

Question 26

This shows **regular points** of **constrictions**

Answer 26

Pseudohyphae

Question 26

This candida spp. has ***true* septate hyphae**

Answer 26

C. albicans

Question 27

Which candida has a **smaller blastoconidia** at **1-4 um**?

Answer 27

C. glabrata

Question 28

Cause **meningitis**, pulmonary disease and septicemia. **Major cause** of opportunistic infections w/ AIDS

Answer 28

Cryptococcus spp.

Question 28

Causes **paronychia**, onychomycosis, vulvovaginitis (**fish-eye**), and **thrush**

Answer 28

Candida spp.

Question 29

Commonly found in **soil** contaminated with **pigeon droppings**

Answer 29

Cryptococcus spp.

Question 30

Cryptococcus spp. is **acquired** through?

Answer 30

inhalation

Question 31

**Most notable pathogen** of the Cryptococcus spp.

Answer 31

C. neoformans

Question 32

**Exhibit polysaccharide capsules** that protect it from dry conditions

Answer 32

Cryptococcus spp.

Question 33

**Most common sample** for Cryptococcus spp.

Answer 33

CSF

Question 34

**Less sensitive** and is able to **delineates** the **large capsule** due to the **inability** of the ink to penetrate the capsule

Answer 34

India Ink

Question 34

**Most widely used method** in testing for ***Cryptococcus spp.***

Answer 34

India Ink

Question 35

Aside from India ink, what is the other test utilized to test for Cryptococcus spp.

Answer 35

Cryptococcal Antigen Detection (CAD)

Question 36

**Opportunistic**, **atypical** fungus and ***acquired in early life***

Answer 36

Pneumocystis

Question 36

***Microscopically***, it appears as spherical, single or **multiple-budding**. Thick walled, 2-15 um diameter, and has a **polysaccharide capsule**

Answer 36

C. neoformans

Question 37

**Asymptomatic** in ***immunocompetent*** individuals.

Answer 37

Pneumocystis

Question 38

**First considered** as ***protozoan*** (parasite)

Answer 38

Pneumocystis

Question 39

What are the **two agents** of Pneumocystis?

Answer 39

P. carinii & P. jirovecii

Question 40

**Previously classified** as **protozoa** and is ***commonly founds in rats***

Answer 40

P.carinii

Question 41

Often **recovered** from **humans**

Answer 41

P.jirovecii

Question 42

**Sugar fermentation test** (turbidity, change in color). This identifies **which carbohydrates** a ***yeast*** can use **aerobically as a sole carbon source**.

Answer 42

Carbohydrate Assimilation

Question 43

***Presumptively identify*** C.albicans, C.tropicalis, and about 10 other species

Answer 43

Chromogenic Substrates (CHROMagar Candida)

Question 43

Identification using CHROMagar, is based on **different colony colors**, depending on the breakdown of ____________ by the different species

Answer 43

chromogenic substrates

Question 43

**Differential media**; morphologic characteristic is possible

Answer 43

Chromogenic Substrates

Question 44

**Allows identification** of morphology of yeasts such as: - Blastoconidia - Chlamydoconidia - Pseudohyphae - Arthroconidia

Answer 44

Cornmeal Agar

Question 45

The **characteristic budding yeast** forms usually seen on **direct mounts of yeasts**.

Answer 45

Blastoconidia

Question 46

These are produced when the **blastoconidia germinate** to form a **filamentous mat**

Answer 46

Pseudohyphae

Question 46

The ________ **help determine** whether the structures are **true hyphae or pseudohyphae**

Answer 46

cross-walls

Question 47

Its cross-walls are **constricted** and ***not true septations***

Answer 47

Pseudohyphae

Question 48

________ remain **parallel** at cross- walls, with ***no indentation***

Answer 48

True hyphae

Question 49

Begin as **true hyphae** but **break apart at the cross walls with maturity**

Answer 49

Arthroconidia

Question 50

Determine the **ability of yeasts to use nitrate** as the **sole source of nitrogen**

Answer 50

Potassium Nitrate Assimilation (KNO3)

Question 51

This organism is the **+Control** in Potassium Nitrate Assimilation (KNO3)

Answer 51

Cryptococcus albidus

Question 52

This organism is the **-Control** in Potassium Nitrate Assimilation (KNO3)

Answer 52

C. albicans

Question 52

Detection of isolates **producing the enzyme urease** is through?

Answer 52

Christensen urea agar

Question 53

In this test, clinically significant ***Candida* spp. are negative**, while most ***Cryptococcus* are positive**

Answer 53

Urease

Question 54

Produces **chlamydoconidia** **along with hyphae**

Answer 54

C. albicans

Question 55

Causes candidiasis in which skin folds are involved

Answer 55

Intertriginous candidiasis

Question 56

Affects tissues surrounding the nails

Answer 56

Paronychia

Question 57

Affects nails and nail beds

Answer 57

Onchomycosis

Question 58

Causes fish eye

Answer 58

Vulvovaginitis