Fungi II Flashcards

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1
Q

Primary infections by these systemic mycoses causing organisms are usually in the

A

Lung

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2
Q

Most primary infections are inapparent and self-limiting, recognized only by immune response or

A

X-ray

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3
Q

Organisms are dimorphic, grow as yeast in tissue and mycelia in culture under usual conditions

A

Systemic mycoces organisms

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4
Q

The organisms that cause systemic mycoses can be converted to yeast form by culture on

A

Blood agar

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5
Q

Cultures of mold forms are identified by reaction of soluble antigens with specific antisera. This is called the

A

Exoantigen test

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6
Q

This is an Oucherlony double-diffusion test; a line of identity is considered

A

Diagnostically significant

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7
Q

A dimorphic fungus; in tissue Cryptococcus grows as a heavily

A

Encapsulated yeast

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8
Q

A dimorphic fungus; in tissue Cryptococcus grows as a heavily encapsulated yeast. It is the imperfect stage of a

A

Basidiomycete Filobasidiella

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9
Q

Like S. pneumoniae, H. influenzae, and N. meningitidis, it is a heavilyencapsulated pathogen that initially infects the respiratory tract and can spread from there to the brain and/or meninges

A

Cryptococcus

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10
Q

Straddles the boundary between ‘pathogen’ and ‘opportunist’

A

Candida

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11
Q

In clinical material, can appear as yeast, hyphae, or pseudophyphae

A

C. albicans

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12
Q

A diagnostic feature which separates C. albicans from other Candida is formation of

A

“Germ tubes” when yeast are placed in serum

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13
Q

Buds which in serum elongate to form the beginnings of hyphae

A

Germ tubes

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14
Q

Chronic mucocutaneous candidiasis is a hallmark of defects in

A

Cell-mediated immunity

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15
Q

Ubiquitous; important pathogens of AIDS patients, transplant recipients, and patients receiving anticancer therapy

A

Opportunistic fungal pathogens

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16
Q

What are three examples of opportunistic fungal pathogens?

A

Aspergillus, zygomyces, and pneumocystis carinii

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17
Q

A large genus, ubiquitous in soil and plant material.

-The most frequent pathogen is A. fumigatus although other species are common causes of disease

A

Aspergillus

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18
Q

The most frequent pathogen of aspergillus is

A

A. fumigatus

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19
Q

Most aspergillus infections are

A

Pulmonary

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20
Q

Most aspergillus infections are pulmonary. Infection can be local and non-invasive [‘Aspergilloma’] or invasive and

A

Necrotizing

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21
Q

Can cause thrombosis, infarction, necrosis, and hemorrhage if they penetrate the walls of a blood vessel, and can also disseminate the infection to other sites

A

Hyphae

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22
Q

A potent allergen and can cause severe bronchopulmonary reactions in atopic individuals and those heavily [occupationally] exposed

A

Aspergillus

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23
Q

We can treat aspergillus infections with

A

Amphotericin/fluorocytosine or one of the newer azoles

24
Q

Even with treatment, mortality from aspergillus infection is

A

50-90%

25
Q

Cause upper or lower respiratory tract disease in immunodeficient patients

A

Zygomyces [Mucor, Rhizopus]

26
Q

Tissue hyphae from zygomycetes can be distinguished from those of other fungi by their breadth, sparse/absent septae, tendency to branch at

A

Right angles

27
Q

Other fungi tend to branch at

A

Acute angles

28
Q

A ubiquitous organism, to which virtually 100% of the U.S. population develops antibodies in childhood

A

Pneumocystis carinii

29
Q

Prior to widespread prophylaxis, many AIDS patients developed

A

Pneumocystis carinii pneumonia [PCP]

30
Q

Diagnosis is usually made by staining broncho-alveolar lavage fluid

A

Pneumocystis carinii infection

31
Q

What are the three genera of opportunists that infect humans?

A

Encephalitozoon, Enterocytozoon, and Nosemia

32
Q

Transmission is via contaminated food or water. Life cycle is similar to that of Apicomplexa

A

Opportunists

33
Q

The infectious form of the opportunist is the

A

Spore

34
Q

Inside the spore wall the cytosol of the microsporidian is continuous with the lumen of a long coiled

A

Polar filament

35
Q

When a spore contacts a host cell the filament everts and pierces the host-cell

A

Plasma membrane

36
Q

Osmotic flow of water into the spore forces the cytoplasm of the parasite through the polar filament and into the cytosol of the host cell, where it becomes surrounded by

A

Membrane

37
Q

Once inside a host cell, a spore develops into a trophozoite and then a

A

Schizont

38
Q

After further mitotic and meiotic divisions and formation of zygotes, infectious spores are formed and released by

A

Host-cell lysis

39
Q

Have the smallest genomes of any eukaryotes

  • 2 mb, smaller than many bacteria
A

Microsporidia

40
Q

Mostly intestinal, eye, or systemic infections, although any tissue can become infected

A

Microsporidia opportunists

41
Q

An infected expectant mother can infect her fetus transplacentally if the infectio is from

A

Microsporidia

42
Q

Used to treat intestinal microsporidia infections

A

Albendazole

43
Q

Have been used successfully to treat microsporidial eye infections

A

Azoles

44
Q

The “Rose Gardener’s” disease

A

Sporotrichosis (caused by S. Shcenkii)

45
Q

Macro life with an Amphipathic ring structure

A

Amphotericin B

46
Q

The non-polar side binds tightly to ergosterol in fungal cell membranes and the polar side forms pores for leak from cells

A

Amphotericin

47
Q

The crucial link between amphotericin and ergosterol

A

Mycosamine sugar unit

48
Q

Drug of choice for almost all life-threatening systemic fungal infections

A

Amphotericin B

49
Q

Flucytosine is removed by the kidney in

A

3-6 Hours

50
Q

Unlike amphotericin B which binds directly to ergosterol, these drugs target the 3rd step in the biosynthesis of ergosterol

A

Azoles

51
Q

Cause accumulation of toxic methylsterols that inhibit membrane enzymes

A

Azoles

52
Q

Binds less efficiently to mammalian p450s,offering some specificity toward fungal cells

A

Azoles

53
Q

The most potent azole

  • wide spectrum
  • used orally
A

Itraconazole

54
Q

Triazole that least affects the liver enzymes?

A

Fluconazole

55
Q

Newest anti-fungal agents

-cell wall disrupters

A

Echinocandins

56
Q

Water-soluble semi-synthetic lipopeptide derivative of pneumocandin B

A

Echinocandins