Agents of Yeast Infections Flashcards

1
Q

These are the three major of agents:

A

 Candida
 Cryptococcus
 Pneumocystis

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2
Q

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.

A

Candida albicans

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3
Q

Yeast fungi can be classified into two groups:

A

Yeast

Yeastlike

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4
Q

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

A

yeasts

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5
Q

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

A

yeastlike fungi

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6
Q

Macroscopic characteristics:.
Color:
Texture:

A

 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

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7
Q

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

A

phaeoid yeasts,

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8
Q

 most notorious agents of yeast infection

 Clinical disease ranges from superficial skin infections to disseminated disease

A

Candida

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9
Q
  • 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.
A

C. albicans

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10
Q

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.

A

thrush

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11
Q
  • 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.
A

C. glabrata

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12
Q
  • 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.
A

C. auris

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13
Q

Other notable species of Candida include______, _______

A

C. krusei and C. tropicalis.

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14
Q

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.

A

C. parapsilosis

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15
Q

 important causes of meningitis, pulmonary disease, and septicemia

A

Cryptococcus

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16
Q

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

A

C. neoformans

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17
Q

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

A

Cryptococcus

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18
Q

 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

A

C. gattii

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19
Q

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

A

India ink or nigrosine

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20
Q

 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.

A

cryptococcal antigen tests

21
Q

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

A

C. neoformans and C. gattii

22
Q

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

A

cryptococcus

23
Q

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

A

positive

24
Q

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

A

phenol oxidase

25
Q

 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.

A

glycine

26
Q

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

A

Canavanine glycine bromothymol blue agar

27
Q

 noted for their bright salmon pink color.

 They resemble the cryptococci because they bear a capsule and are urease positive

A

Rhodotula

28
Q

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

A

Rhodotula

28
Q

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

A

Rhodotula

29
Q

 inhabit the lungs of many mammals

A

Pneumocystis

30
Q

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

A

Pneumocystis carinii

31
Q

 _________is the species most commonly found in rats,

A

P. carinii

32
Q

 is the species most often recovered from humans.

A

P. jirovecii

33
Q

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

A

2 to 4 years of age.

34
Q

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

A

pneumocystis

35
Q

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

A

pneumocystis

36
Q

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

A

Pneumocystis

37
Q

nonfilamentous fungus.

A

pneumocystis

38
Q

The life cycle (3) three stages:

A

 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)

39
Q

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.

A

intracystic bodies

40
Q

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

A

True

41
Q

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

A
o	bronchoalveolar lavage (BAL) fluid 
o	transbronchial biopsy 
o	tracheal aspirate
o	pleural fluid
o	induced sputum – least productive specimen
42
Q

 Lavage and sputum specimens are often prepared using a _______

A

cytocentrifuge

43
Q

 Histologic stains, such as ____ and ________

A

Giemsa and Gomori methenamine silver stains

44
Q

 With the ______, the cyst wall stains black.

A

methenamine silver stain

45
Q

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

A

cyst

46
Q

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

A

Giemsa stain

47
Q

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

A

Calcofluor white

48
Q

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

A

blue-white