Agents of Yeast Infections

Question 1

These are the three major of agents:

Answer 1

 Candida
 Cryptococcus
 Pneumocystis

Question 2

It is considered as the fourth most common cause of blood borne infection in United States and accounting 10% - 15% of hospital-acquired septicemia cases.

Answer 2

Candida albicans

Question 3

Yeast fungi can be classified into two groups:

Answer 3

Yeast

Yeastlike

Question 4

Isolates that reproduce sexually, by forming either ascospores or basidiospores, are truly ___

Answer 4

yeasts

Question 5

isolates that are not capable of sexual reproduction or whose sexual state has not yet been discovered

Answer 5

yeastlike fungi

Question 6

Macroscopic characteristics:.
Color:
Texture:

Answer 6

 Color – white to cream or tan, with a few species forming pink- to salmon-colored colonies.
 Texture – mucoid (Cryptococcus spp.), butter-like, velvety to wrinkled

Question 7

Some yeast isolates, referred to as _____ are darkly pigmented because of melanin in their cell walls

Answer 7

phaeoid yeasts,

Question 8

 most notorious agents of yeast infection

 Clinical disease ranges from superficial skin infections to disseminated disease

Answer 8

Candida

Question 9

• the premier cause of yeast infection in the world.
• recovered as normal biota from a variety of sites, including skin, the oral mucosa, the digestive tract, and the vagina.

Answer 9

C. albicans

Question 10

One of the most widely recognized manifestations of C. albicans infection is _____ (oropharyngeal candidiasis), an infection of the oral mucosa and recognized as an indicator of immunosuppression.

Answer 10

thrush

Question 11

• common Candida species that causes disease and may account for 21% of all urinary yeast isolates.
• Infections associated with this tend to be aggressive in patients with multiple comorbidities and may be difficult to treat with traditional antifungal therapy.

Answer 11

C. glabrata

Question 12

• multidrug-resistant yeast linked to high mortality rates associated with hospital-acquired infections worldwide.
• likely transmitted from patient to patient in health care settings and has caused several outbreaks in
  numerous countries.

Answer 12

C. auris

Question 13

Other notable species of Candida include______, _______

Answer 13

C. krusei and C. tropicalis.

Question 14

It has become a major cause of outbreaks of nosocomial infections. These isolates are identified by the differences in their carbohydrate assimilation patterns and other secondary testing procedures.

Answer 14

C. parapsilosis

Question 15

 important causes of meningitis, pulmonary disease, and septicemia

Answer 15

Cryptococcus

Question 16

 it is the most notable pathogen in this Cryptococcus genus, is a major cause of opportunistic infection in patients with AIDS.

Answer 16

C. neoformans

Question 17

 commonly found in soil contaminated with pigeon droppings and is most likely acquired by inhalation

Answer 17

Cryptococcus

Question 18

 It is an emerging pathogen, particularly in the Pacific Northwest of the United States, similar to those caused by C. neoformans, targeting primarily immunocompromised patients. It an also cause disease in immunocompetent hosts

Answer 18

C. gattii

Question 19

used primarily to examine cerebrospinal fluid for the presence of the encapsulated yeast Cryptococcus neoformans

Answer 19

India ink or nigrosine

Question 20

 The use of India ink preparation is being replaced by use of _________because of the former’s low sensitivity and an easy-to-use lateral-flow assay, are recommended for routine use in clinical microbiology laboratories.

Answer 20

cryptococcal antigen tests

Question 21

 The cryptococcal antigen assays detect ___ and ____ in CSF and serum

Answer 21

C. neoformans and C. gattii

Question 22

are noted for producing blastoconidia only, without producing true hyphae or pseudohyphae on cornmeal agar

Answer 22

cryptococcus

Question 23

 All species of the Cryptococcus genus are urease ____, and the nitrate reaction differs

Answer 23

positive

Question 24

 Production of _____ is a feature differentiating C. neoformans from many other Cryptococcus spp.

Answer 24

phenol oxidase

Question 25

 A key laboratory characteristic is that C. gattii uses ___ as a sole carbon and nitrogen source in the presence of canavanine, whereas C. neoformans does not.

Answer 25

glycine

Question 26

 ________ is commercially available and can be used to differentiate between C. neoformans and C. gattii.

Answer 26

Canavanine glycine bromothymol blue agar

Question 27

 noted for their bright salmon pink color.  They resemble the cryptococci because they bear a capsule and are urease positive

Answer 27

Rhodotula

Question 28

 They resemble the cryptococci because they bear a capsule and are urease positive. And some species are nitrate positive

Answer 28

Rhodotula

Question 28

 They are not common agents of disease but have been known to cause opportunistic infections.

Answer 28

Rhodotula

Question 29

 inhabit the lungs of many mammals

Answer 29

Pneumocystis

Question 30

 _______was originally classified with the protozoa, but nucleic acid sequencing showed conclusively that the organism is a fungus.

Answer 30

Pneumocystis carinii

Question 31

 _________is the species most commonly found in rats,

Answer 31

P. carinii

Question 32

 is the species most often recovered from humans.

Answer 32

P. jirovecii

Question 33

 acquired early in life; serologic studies have shown that most humans have antibodies or antigens by ____

Answer 33

2 to 4 years of age.

Question 34

 it was initially identified as the causative agent in interstitial plasma cell pneumonia seen in malnourished or premature infants.

Answer 34

pneumocystis

Question 35

 Since the early 1980s, it has remained one of the primary opportunistic infections found in patients with AIDS

Answer 35

pneumocystis

Question 36

 Patients infected with ______ may have nonproductive cough, difficulty breathing, and a low-grade fever

Answer 36

Pneumocystis

Question 37

nonfilamentous fungus.

Answer 37

pneumocystis

Question 38

The life cycle (3) three stages:

Answer 38

 Trophozoite – 1 to 5 µm in size and is irregularly shaped  Pre-cyst – 5 to 8 µm  Cyst – thick-walled sphere of about 8 µm containing up to eight intracystic bodies.  MOT: respiratory route – cyst (infective stage)

Question 39

The spores or _____ are released from the cyst in the lung, and these trophic forms multiply asexually by binary fission on the surface of the epithelial cells (pneumocyte) lining the lung.

Answer 39

intracystic bodies

Question 40

Sexual reproduction by trophozoites also occurs, first producing a precyst and then the cyst containing spores or intracystic bodies.

Answer 40

True

Question 41

Diagnosis was made by finding the cyst or trophozoite in tissue obtained through open lung biopsy. Specimens:

Answer 41

``` o bronchoalveolar lavage (BAL) fluid o transbronchial biopsy o tracheal aspirate o pleural fluid o induced sputum – least productive specimen ```

Question 42

 Lavage and sputum specimens are often prepared using a _______

Answer 42

cytocentrifuge

Question 43

 Histologic stains, such as ____ and ________

Answer 43

Giemsa and Gomori methenamine silver stains

Question 44

 With the ______, the cyst wall stains black.

Answer 44

methenamine silver stain

Question 45

often have a punched-out ping-pong ball appearance.

Answer 45

cyst

Question 46

 With the _____, the organism appears round, and the cyst wall is barely visible.

Answer 46

Giemsa stain

Question 47

 _____ can be used to screen specimens for Pneumocystis and other fungi. This stain detects any organism that contains chitin in its cell wall.

Answer 47

Calcofluor white

Question 48

 Fungi, yeasts, and Pneumocystisspp. will fluoresce with a _______color when stained and viewed microscopically with ultraviolet light.

Answer 48

blue-white