MYCO & VIROLOGY L3 (Midterms- Opportunistic and Systemic) Flashcards

1
Q

Seen in immunocompromised patients.
Commonly encountered as saprobes

A

Opportunistic mycoses

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2
Q

One of the most commonly encountered fungi in the lab (common in peanuts)

A

Aspergillus spp.

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3
Q
  • Second most isolated fungus after Candida spp.
  • Widespread in the environment
  • Conidia are easily dispersed in the environment
A

Aspergillus spp.

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4
Q

Aspergillus spp. are transmitted by?

A

Inhalation

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5
Q

Aspergillus spp. septate hyphae branches out at _____ degrees?

A

45

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6
Q

In the _________, conidia of aspergillus spp. germinate and invade the tissue

A

lung air spaces

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7
Q

IDENTIFY based on clinical manifestations:

  • Pulmonary or sinus fungus balls
  • Allergic bronchopulmonary aspergillosis
  • External otomycosis (auditory canal)
  • Mycotic keratitis
  • Onychomycosis (nail and surrounding tissues)
  • Sinusitis
  • Endocarditis
A

Aspergillus spp.

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8
Q

In terms of structure, aspergillus has a _______
hyphae and conidiophore. And if you look closely, they have a vesicle at the end of the condiophore, these vesicles have ________ attached to them

A

septated; mutulae

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9
Q

Its other characteristics include an erect conidiophore arising from a foot cell within the vegetative hyphae

A

Aspergillus spp.

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9
Q

A supporting structure where the phialides attached.

A

Metulae

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9
Q

Conidia of aspergillus spp. are produced from the?

A

phialides

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10
Q

What makes this unique is that it has a metula/metulae before the phialide

A

Aspergillus spp.

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10
Q

Laboratory dx for aspergillus spp.

A
  • Antigen-protein based assays
  • Nucleic Acid Amplification Assay
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11
Q

What is the downside of Antigen-protein based assays?

A

not true to all species of Aspergillus because it can have cross reactions

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11
Q

This organism has a fungus ball

A

Aspergillus spp.

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12
Q

This assay is used for monitoring patients who are at high risk ofdeveloping invasive fungal infections

A

Antigen-protein based assays

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13
Q

What is the downside of Nucleic Acid Amplification Assay?

A

not readily available for fungi in general

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14
Q

Enumerate the different species of aspergillus

A
  • A. fumigatus
  • A. flavus
  • A. niger
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15
Q

When cultured it rapidly grows (1-5 days) and manifests a yellow-green colony

A

Aspergillus flavus

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16
Q

Microscopically, its phialides give rise to short chains of yellow orange elliptical or spherical conidia

A

A. flavus

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17
Q

Produced directly from the vesicle

A

Uniseriate

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18
Q

Produced from a primary row of cells called metulae

A

Biseriate

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19
Q

Macroscopically, it produces darkly pigmented, roughened spores

A

A. niger

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20
Q

Microscopically, its hyphae are hyaline and septate

A

A. niger

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21
Q

Aspergillus niger’s colony mature within?

A

2-6 days

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22
Q

Young colony of A. niger appears?

A

yellow

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23
Q

Its appears black dotted surface due to conidia

A

Old colony of A. niger

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24
Q

Remains buff or cream colored

A

reverse colony of A. niger

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25
Q

IDENTIFY based on structure:
- Septate hyphae
- Long condiophores
- Large metulae
- Smaller phialides (biseriate)

A

A. niger

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26
Q

These can also be commonly seen in clinical laboratory but its association with the clinical disease that it can cause is still unclear.

A

A. niger

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26
Q

A. niger is known to cause?

A

fungus ball and
otitis externa

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26
Q

It is a rapid grower (2-6 days), has blue-green appearance and is thermotolerant at 45C

A

A. fumigatus

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27
Q

IDENTIFY based on microscopic characteristics:
- Septate hyphae
- “foot cell” at base -L or T-shaped

A

A. fumigatus

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28
Q

Differentiate the different species of Aspergillus based on their rate of growth.

A

A. fumigatus: rapid grower; 2-6 days

A. flavus: rapid grower; 1-5 days

A. niger: rapid grower; 2-6 days

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29
Q

Common environmental isolates associated with soil and plants

A

Mucorales

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30
Q

They contaminate grains, breads, and fruits and are most often associated with infections of the sinuses, lungs, and skin of immunocompromised patients

A

Mucorales

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31
Q

IDENTIFY based on general microscopic characteristics:

  • Saclike fruiting structures (sporangia)
  • Sporangium is formed at tip of sporangiophore
  • Septate hyphae
  • Rootlike structure
A

Mucorales

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32
Q

What do you call the septate hyphae of mucorales?

A

stolon

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33
Q

The rootlike structure of mucorales is called?

A

rhizoids

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34
Q

Agents of Mucorales

A
  • Cunninghamella
  • Lichtheimia
  • Mucor
  • Rhizopus
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35
Q

Central axis of the sporangia
(multispored structure)

A

columella (singular)

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36
Q

Swelling of the sporangiophore below the columellae (plural)

A

Apophysis

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37
Q

Some species (of mucorales) also produce _____ that hold the sporangiophore within the soil or growth substrate. Which are then connected to a branching root, or ______

A

rhizoids; stolon

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38
Q

These attach at contact points where rootlike structures (rhizoids) may appear and anchor the organism to the agar surface

A

Stolons

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39
Q

Marked propensity for vascular invasion. Rapidly produce thrombosis and necrosis of tissue

A

Mucormycosis

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40
Q

Common presentation of mucomycosis

A

Rhinocerebral form

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41
Q

Potential means of retroorbital spread (i.e., invasion into the brain)

A

Perineural invasion

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42
Q

Specimens used for Mucorales testing/identification

A
  • Deep tissue or lesion sample
  • Nasal discharge or scrapings
  • Respiratory samples
42
Q

Specimens tested for mucorales should be transported within how many hours upon collection?

A

2 hours

43
Q

TRUE OR FALSE: Mucorales are not sensitive to environmental changes

A

FALSE. Mucorales are sensitive

43
Q

Blood cultures are not ideal for this type of fungi

A

Mucorales

44
Q

Stains used for dectecting/testing for presence of mucorales

A

Calcoflour white and KOH

45
Q

Molecular methods used for dectecting/testing for presence of mucorales

A
  • Nucleic acid testing
  • Polymerase chain reaction (PCR) Amplificat
46
Q

Agars used for cultivating mucorales

A
  • Potato dextrose
  • 2% Malt
  • Cherry decoction (acidic) agar
47
Q

These contain high concentrations of carbohydrates that inhibits the production of asexual fruiting bodies that are required for the proper identification of the Mucorales species

A

Growth media

48
Q

IDENTIFY based on morphological colonial characteristics:

  • fluffy, white to gray or brown
  • Hyphae diffusely covers the surface of the agar within 24 to 96 hours
  • Rapid grower of hyphae
  • “lid lifter”
A

Mucorales

48
Q

Reproduction characteristics of Mucorales

A

sexually: zygospores
asexually: sporangiospores

49
Q

IDENTIFY based on microscopic apperance:

  • Erect sporangiophores
  • Few septate
  • Internodal rhizoids (short, thin projections that anchor the growing cells)
A

Lichtheimia

49
Q

IDENTIFY:
-Can be recovered from the sinuses
- Sporangiophores
- Erect
- branching into several vesicles that bear
sporangioles
- White to gray cottony colony

A

Cunninghamela

50
Q

IDENTIFY:
- Agent for rhinocerebral mucormycosis
- found in patients with diabetes and ketoacidosis

A

Lichtheimia

51
Q

Its hyphae are broad and ribbon-like

A

Lichtheimia

52
Q

Agent of disseminated disease

A

Mucor

53
Q

Rhizoids are absent. Its sporangia remain intact

A

Mucor

54
Q

Colony characteristics of Mucorales

A

Dirty white-mousy brown colonies

55
Q

IDENTIFY:

  • Most common Mucorales causing human disease
  • May be recovered from almost any source
  • Rhizoids appear opposite of stolon
  • Rapid grower
  • erect sporangiophores terminating in dark sporangia and sporangiospores
A

Rhizopus

56
Q

Slide culture preparations shows “umbrella-shaped”

A

Rhizopus

57
Q

Enumerate the different species of Mucorales

A
  • Cunninghamella
  • Lichtheimia
  • Mucor
  • Rhizopus
58
Q

Pulmonary disease in immunocompromised
patients

A

Geotrichum

59
Q

Microscopically, its arthroconidia formed from vegetative hyphae and occur singly or may be branched

A

Geotrichum

60
Q

Colonies appear white to cream and yeastlike and can be confused with Trichosporon spp. Septate and hyaline saprophyte

A

Geotrichum

61
Q

IDENTIFY:
- Inhibited at 37°C
- rarely cause infections
- disease involve chronic fungal sinusitis
- Septate and hyaline saprophytes

A

Pencillium

62
Q

Microscopically, its conidiophores are erect, sometimes branched, and metulae bearing one or several phialides on which oval to ovoid conidia are produced in long, loose chains

A

Pencillium

63
Q

Its a rapid grower, with colonies usually in shades of green or blue-green

A

Pencillium

64
Q

IDENTIFY:
- share several characteristics with opportunistic fungi
- Any opportunistics fungal agent has the capacity to disseminate to sites
- Generally shows dimorphism
22C - fungi
35-37C -Yeast

A

Systemic mycoses

65
Q

Most prevalent in middle-aged men as are other systemic mycoses, presumably because occupational and recreational exposure to soil is often greater among men

A

Blastomyces dermatitidis

66
Q

May exhibit flulike symptoms but most often are asymptomatic

A

Blastomyces dermatitidis

67
Q

Also known as Gilchrist disease, North American blastomycosis, and Chicago disease. It occurs primarily in North America and parts of Africa.

A

Blastomyces dermatitidis

68
Q

What are the two species of Blastomyces?

A
  • Blastomyces dermatitis and Blastomyces gilchristii
69
Q

Macroscopically, it shows slow to moderate growth. White to dark tan, Young colonies is tenacious, older colonies glabrous to woolly

A

Blastomyces
dermatitidis at
22C (mold form)

70
Q

Culture media & temperature for Blastomyces
dermatitidis (yeast form)

A

Blood agar 37C

71
Q

Microscopically, it appears oval, pyriform to globose smooth conidia borne on short, lateral hyphalike conidiophores

A

Blastomyces dermatitidis at 22C (mold form)

72
Q

Large yeast (8-12 um). Blastoconidia attached
by broad base

A

Blastomyces dermatitidis (yeast form)

73
Q

Acquired by the inhalation of the microconidia

A

Histoplasma capsulatum

74
Q

IDENTIFY:
- Microconidia are phagocytized by macrophages in the pulmonary parenchyma
- Usually asymptomatic in intact immune defenses
- Calcification may appear in the lungs, liver, and spleen

A

Histoplasma capsulatum

75
Q

Associated with reticuloendothelial cytomycosis, “cave disease”, spelunker’s disease, and Darling disease

A

Histoplasma capsulatum

76
Q

This organism resides in soil with a high nitrogen content, particularly in areas heavily contaminated with bat and bird guano

A

Histoplasma capsulatum

77
Q

Lab dx for Histoplasma capsulatum

A

Enzyme immune assay methods

78
Q

Enzyme immune assay methods can be performed on:

A
  • Serum, CSF, and Urine
79
Q

Macroscopically, it is characterized by slow growth, appears white to dark tan with age, and wholly, cottony, or granular

A

Histoplasma
capsulatum at 22C
(mold form)

80
Q

Microscopically, its microconidia are small, one- celled, round, smooth (2-5 um), its tuberculated macroconidia are large, round (7- 12 um), and has hyphalike conidiophores

A

Histoplasma
capsulatum at
22C
(mold form)

81
Q

IDENTIFY: Small, oval, yeast (2-5 um)

A

Yeast form of Histoplasma
capsulatum

82
Q

Culture media and temperature utilized for cultivating Histoplasma capsulatum (yeast form)

A

Pines medium, glucose-cysteine blood, or BHI agar-blood, 37C

83
Q

IDENTIFY:
- Primary route is pulmonary
- Formation of ulcerative granulomatous lesions of the buccal, nasal, and occasionally gastrointestinal mucosa
- narrow range of temperature tolerance

A

Paracoccidiodes brasilensis

84
Q

This organism often likes cooler areas of the body

A

Paracoccidiodes brasilensis

85
Q

Disease associated with Paracoccidiodes brasilensis

A

Paracoccidioidomycosis
and Lutz-Splendore-Almeida disease

86
Q

Colonies frequently only produce sterile
hyphae

A

Paracoccidiodes brasilensis

87
Q

Fresh isolates may produce conidia similar to those of B dermatitidis

A

Paracoccidiodes brasilensis

88
Q

Macroscopically, it is characterized by slow growth.
White to beige, and colony is glabrous,leathery, flat to wrinkled, and folded or velvety

A

Paracoccidiodes brasilensis

89
Q

IDENTIFY:
Multiple blastoconidia budding from single, large yeast (15-30 um)

A

Paracoccidiodes brasilensis (yeast form)

89
Q

Paracoccidiodes brasilensis (yeast form) culture media & temperature

A

BHI agar-blood, 37

90
Q

Most virulent of all human mycotic agents

A

Coccidioides spp.

90
Q

Inhalation of only a few arthroconidia produces
_______________ (pulmonary disease)

A

primary coccidioidomycosis

91
Q

Symptom may present as allergic manifestations such as:
- Toxic erythema
- Erythema nodosum
(desert bumps)
- Erythema multiforme (valley fever)
- Arthritis (desert rheumatism).

A

Coccidioides spp.

92
Q

Filipinos and blacks run the highest risk of
dissemination

A

Coccidioides spp.

92
Q

Fever, respiratory distress, cough, anorexia, headache, malaise, and myalgia. can be present for 6 weeks or longer

A

Respiratory symptoms of Coccidioides spp.

93
Q

Include nodules, cavitary lung disease, and/or progressive pulmonary disease

A

Secondary coccidioidomycosis

94
Q

Macroscopically, it is characterized by rapid growth, white to tan to dark gray

A

C. immitis and C. posadasii at 22C

95
Q

Macroscopically, its young colonies
are tenacious, older colonies are cottony, and tend to grow in concentric rings

A

C. immitis and C. posadasii at 22C

96
Q

Microscopically, C. immitis and C. posadasii have alternating one- celled ________ arthroconidia with disjunction cell

A

“barrel- shaped”

96
Q

_________ can be converted to the _________ in modified converse medium at 40C in 5% to 10% carbon dioxide

A

Coccidioides immitis; spherule phase

96
Q

IDENTIFY:
- Usually seen in endemic region of Southeast Asia
- Infections are usually disseminated, with multiple organ involvement
- Appears as cutaneous lesions
- Can be typically fatal

A

Talaromyces marneffei

97
Q

Only true pathogen of Talaromyces spp.

A

Talaromyces marneffei

98
Q

This organism is seen in Wright stained smears

A

Talaromyces marneffei yeast form

98
Q

Specimen used for Talaromyces marneffei

A
  1. Skin lesions
  2. Biopsy specimens
99
Q

When cultured, it appears sparse green arial hyphae, reddish-brown vegetative hyphae, and produces red diffusible pigment

A

T. marneffei mold form

99
Q

May resemble H. capsulatum. Oval to cylindric measuring 3-6 um long

A

Biopsy specimen of T. marneffei

100
Q

Also known as desert bumps

A

Erythema nodosum

101
Q

Erythema multiforme is also called

A

Valley fever

101
Q

Also known as desert rheumatism

A

Arthritis