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T1 - Phase 2 - Systems Modules (I) > Infectious Disease - Fungal Basics > Flashcards

Infectious Disease - Fungal Basics Flashcards

1
Q

What is mycology?

What are mycoses?

A

Study of fungi;

fungal diseases

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2
Q
A
  1. Fungi have one or more nuclei and chromosomes
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3
Q

Fungi are _____karyotes that ____ (do/do not) have membrane-bound organelles (e.g. nuclei).

A

Fungi are eukaryotes that do have membrane-bound organelles (e.g. nuclei).

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4
Q

Are fungi single or multicellular?

A

Can be either

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5
Q

Most fungi are ____robic.

A

Most fungi are aerobic.

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6
Q

What type of medication is used to treat fungal infections?

A

Antimycotics

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7
Q

Fungi are _______ (smaller/larger) and _______-growing (slower/faster) than most bacteria.

A

Fungi are larger and slower-growing than most bacteria.

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8
Q

A mass of fungal filaments (also known as ________) is called a ________.

A

A mass of fungal filaments (also known as hypha) is called a mycelium.

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9
Q

True/False.

Pathogenic fungi are always either yeasts and/or molds.

A

True.

Pathogenic fungi are always either yeasts and/or molds.

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10
Q

Describe yeast morphology.

A

Singular round-to-oval cells

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11
Q

Describe mold morphology.

A

Long multicellular filamentous structures

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12
Q

What does it mean that some fungi are dimorphic?

A

They can exist in two forms

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13
Q

Dimorphic fungi are capable of growing as either ________ or ________. What determines the difference?

A

Dimorphic fungi are capable of growing as either yeasts or molds.

Temperature

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14
Q

Dimorphic fungi are capable of growing as either yeasts or molds.

When are they yeasts?

When are they molds?

A

Yeasts at 37°C;

molds at 25°C

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15
Q

What is oral thrush?

A

Candidiasis of the buccal mucosa

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16
Q

What fungus can often result in otomycoses?

A

Aspergillus

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17
Q

Yeast undergo a _________ process in order to replicate.

The most common example yeast is _________.

_________ is a unique form in that it has a capsule.

A

Yeast undergo a budding process in order to replicate.

The most common example yeast is Candida.

Cryptococcus is a unique form in that it has a capsule.

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18
Q

True/False.

Yeast can be multicellular or single-celled.

A

False.

Yeast are single-celled.

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19
Q

Molds are composed of ________ (filamentous structures) and are ________ (_____-colored).

A common example is ________.

A

Molds are composed of hypha (filamentous structures) and are

dematiaceous (dark-colored).

A common example is Aspergillus.

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20
Q

_______ undergo a budding process in order to replicate.

The most common example _______ is Candida.

Cryptococcus is a unique form in that it has a capsule.

A

Yeast undergo a budding process in order to replicate.

The most common example yeast is Candida.

Cryptococcus is a unique form in that it has a capsule.

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21
Q

_______ are composed of hypha (filamentous structures) and are dematiaceous (dark-colored).

A common example is Aspergillus.

A

Mold are composed of hypha (filamentous structures) and are dematiaceous (dark-colored).

A common example is Aspergillus.

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22
Q
A
  1. Molds produce hyphae that may or may not be partitioned with cross-walls or septa
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23
Q

Fungi can reproduce asexually or sexually, but only the ________ are associated with human disease.

A

Fungi can reproduce asexually or sexually, but only the asexual are associated with human disease.

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24
Q

What is the name for the fungal spores found at the ends of specialized hypha?

Is this sexual or asexual reproduction?

A

Conidia;

asexual

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25
Q

Describe the process of fungal germination / sporulation.

A
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26
Q
A
  1. Ergosterol
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27
Q

Describe fungal dimorphism.

________ in natural habitats: 25°C; ____ oxygen and ____ nutrients

________ in animal hosts: 37°C; ____ oxygen and ____ nutrients

A

Describe fungal dimorphism.

Molds in natural habitats: 25°C; more oxygen and more nutrients

Yeasts in animal hosts: 37°C; less oxygen and less nutrients

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28
Q

Describe the composition of the fungal membrane/wall from in to out.

A

Membrane

Wall

Chitin

Glucans

Mannoproteins (peptidomannan)

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29
Q

Which portion of the fungal wall is thickest?

Which portion is immunogenic?

Chitin — glucans — mannoproteins

A

Glucans;

mannoproteins (peptidomannan)

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30
Q

There are approximately ____ fungi that cause disease in humans.

A

There are approximately 200 fungi that cause disease in humans.

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31
Q

True/False.

Fungi have multiple strong virulence factors.

A

False.

Fungi have multiple weak virulence factors.

E.g.

  • Adherence to cells*
  • Resistance to phagocytosis*
  • Capsule production*
  • Destructive enzymes*
  • Immunomodulating factors*
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32
Q

Most fungal diseases are either:

__________ (hypersensitivities),

__________ (toxin ingestion),

or __________ (systemic disease).

A

Most fungal diseases are either:

allergies,

mycotoxicoses,

or mycoses.

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33
Q

Mold allergies are usually a result of inhaled ______ or ______.

A

Mold allergies are usually a result of inhaled conidia or hypha.

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34
Q

What mold is typically involved in fungal allergies?

Is any fungal replication necessary?

A

Aspergillus;

no

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35
Q

True/False.

Most mycoses are either superficial, cutaneous, subcutaneous, or systemic.

A

True.

36
Q
A

C. Aflatoxin B1

37
Q

Mycotoxicoses result due to ingestion of fungal toxins. What are the two most prominent categories?

A

Ergot alkaloids (e.g. psilocybin);

aflatoxins (B1 especially)

38
Q

Aflatoxin B1 comes from what fungus?

It is known to cause what cancer?

A

Aspergillus;

hepatocellular carcinoma

39
Q

What does it mean that fungal mycoses can be either true or opportunistic?

A

True: dimorphic fungi that cause disease in virtually all hosts

Opportunistic: fungi that cause disease in compromised hosts

40
Q

Which ‘true’ pathogens cause mycoses?

A
  • Histoplasma*;
  • Blastomyces*;
  • Coccidiodes*;
  • Paracoccidiodes*
41
Q

Which ‘opportunistic’ pathogens cause mycoses?

A
  • Candida*;
  • Cryptococcus*;
  • Aspergillus*;
  • Pneumocystis*
42
Q

___% of all nosocomial infections are fungal in nature.

A

10% of all nosocomial infections are fungal in nature.

43
Q

In what geographic regions are Histoplasma infections most common?

A

Eastern U.S.;

southern U.S.;

northern South America;

mid-Africa

44
Q

In what geographic regions are Blastomyces infections most common?

A

The eastern U.S.

45
Q

In what geographic regions are Coccidiodes infections most common?

A

The western U.S.

46
Q

In what geographic regions are Paracoccidiodes infections most common?

A

Central America;

South America

47
Q

Broad-spectrum antibiotic use commonly leads to what fungal infection?

A

Vaginal candidiasis

48
Q

What pulmonary mycoses is considered a hallmark of infection in AIDS patients?

A

Pneumocystis carinii pneumonia

49
Q

What mycoses sometimes results in cerebromeningeal involvement?

A

Cryptococcus

50
Q

Does Candida cause superficial or systemic mycoses?

A

Either

51
Q

True/False.

Aspergillus can cause a variety of infectious patterns, including allergic reactions, mycotoxicoses, non-invasive mycoses, and invasive mycoses.

A

True.

52
Q

Name a few stains/preparations used for direct examination of fungal samples.

A

KOH;

India ink;

Giemsa;

Calcofluor

53
Q

A _______ lamp is a ______ lamp used to detect fluorescence in fungal samples.

A

A Wood’s lamp is a UV lamp used to detect fluorescence in fungal samples.

54
Q

What stains can be used in fungal histology?

A

PAS;

GMS (Gomori’s methenamine silver nitrate)

55
Q

True/False.

Fungi often require special medias for culturing and may need to be cultured at both 25°C and 37°C.

A

True.

56
Q

What process allows for amplification of fungal DNA for analysis?

A

PCR

57
Q

What medication interferes with microtubule activity in fungi?

A

Griseofulvin

58
Q
A
  1. (also 1. to a lesser extent)
59
Q

Types of mycoses:

_________ -infections deeper in the epidermis and its integuments (skin, hair) with host response component

_________ -infections in the dermis, subcutaneous tissues, muscle & fascia. Host response can be severe.

_________ -limited to the outermost layers of the skin and hair with no/minimal host response.

A

Types of mycoses:

Cutaneous -infections deeper in the epidermis and its integuments (skin, hair) with host response component

Subcutaneous -infections in the dermis, subcutaneous tissues, muscle & fascia. Host response can be severe.

Superficial -limited to the outermost layers of the skin and hair with no/minimal host response.

60
Q

Types of mycoses:

Superficial -limited to the outermost layers of the skin and hair. Host response: ___________.

Cutaneous -infections deeper in the epidermis and its integuments (skin, hair). Host response: ___________.

Subcutaneous -infections in the dermis, subcutaneous tissues, muscle & fascia. Host response: ___________.

A

Types of mycoses:

Superficial -limited to the outermost layers of the skin and hair. Host response: minimal or none.

Cutaneous -infections deeper in the epidermis and its integuments (skin, hair). Host response: present.

Subcutaneous -infections in the dermis, subcutaneous tissues, muscle & fascia. Host response: can be severe.

61
Q

What type(s) of mycoses is(are) limited to the epidermis?

A

Superfcial and cutaneous mycoses

62
Q

Name a few infectious agents that are causes of superficial mycoses.

A

Malassezia furfur,

  • Hortae werneckii,*
  • Piedraia hortae,*
  • Trichosporon beigelii*
63
Q

Name a few infectious agents that are causes of cutaneous mycoses.

A

Trichophyton spp.,

Epidermophyton spp.,

Microsporum spp.

64
Q

Name a few infectious agents that are causes of subcutaneous mycoses.

A

Sporothrix schenckii,

  • Fonsecaea spp.,*
  • Exophiala,*
  • Fusarium*
65
Q

Name the presentations illustrated (these are examples of superficial mycoses).

A

A. Pityriasis versicolor

B. Tinea nigra

C. Black piedra

D. White piedra

66
Q

Pityriasis (tinea) versicolor is a superficial infection of the _______ layer of epidermis. Characterized by fawn to brown, or at times, achromatic, _______ patches.

A

Pityriasis (tinea) versicolor is a superficial infection of the horny layer of epidermis. Characterized by fawn to brown, or at times, achromatic, scaly patches.

67
Q

What is the etiological agent of pityriasis (tinea) versicolor?

A

Malassezia furfur

68
Q

Pytyriasis (tinea) versicolor results in what?

Multiple ______pigmented or ______pigmented macules surrounded by normal skin.

  • Can appear in ________ of the body.
  • Skin can be dry and scaly. _____ (is / is not) contagious
  • Pain____, skin may _____ where the spots appear.
  • Spots become more noticeable as the skin tans. The yeast prevents the skin from tanning.
  • In warm climates some people are continuously symptomatic
A

Pytyriasis (tinea) versicolor results in what?

Multiple hyperpigmented or hypopigmented macules surrounded by normal skin.

  • Can appear in any part of the body.
  • Skin can be dry and scaly. is not contagious
  • Painless, skin may itch where the spots appear.
  • Spots become more noticeable as the skin tans. The yeast prevents the skin from tanning.
  • In warm climates some people are continuously symptomatic
69
Q

What infectious agent causes tinea nigra?

A

Hortae werneckii

70
Q

How does tinea nigra appear grossly?

A

Asymptomatic dark lesions on palms and hands

71
Q

Where are black piedra found?

What is the etiological agent?

A

Hard, black, gritty nodules along hair shaft;

Piedraia hortae

72
Q

How are the black piedra caused by Piedraia hortae and/or the white piedra caused byTrichosporon beigelii treated?

A

Shaving affected hairs

73
Q

What is the etiological agent of white piedra?

A

Trichosporon beigelii

74
Q

Where are white piedra found?

What is the etiological agent?

A

White nodules along the hair shaft;

Trichosporon beigelii

75
Q

Which of the following describes ringworm?

Superficial mycoses

Cutaneous mycoses

Subcutaneous mycoses

A

Cutaneous mycoses

76
Q

___________, the causative agent in cases of ringworm, can penetrate and parasitize all layers of skin, hair, and nails and produce significant lesions.

What layers of skin does it affect?

A

Dermatophytes, the causative agent in cases of ringworm, can penetrate and parasitize all layers of skin, hair, and nails and produce significant lesions.

Keratinized epidermdal layers

77
Q

What are the three main dermatophytes that cause ringworm?

A
  • Trichophyton*,
  • Microsporum*,
  • Epidermophyton floccosum*
78
Q

Describe the difference between fungal macroconidia and microconidia.

A

Macroconidia:

  • Large, complex, can be multinucleated

Microconidia:

  • Smaller single, single nucleus
79
Q

True/False.

There are many different types / causative agents of ringworm.

A

True.

80
Q

Another term for athlete’s foot is?

Another term for scalp ringworm is?

Another term for jockitch is?

Another term for body ringworm is?

A

Tinea pedis;

tinea capitis;

tinea cruris;

tinea corporis

81
Q

How do chronic cutaneous mycoses (dermatocyte) present?

A

Chronic infections are associated with:

- A minimal tissue response

- High antibody titers (typically with allergic responses)

- Failure to clear the infection

82
Q

What are dermatophytid reactions?

A

Hypersensitive state, probably resulting from circulating fungal antigens (lesion does NOT have fungi)

(multiple forms: vesicles, papules, erysipelas-like plaques, erythema nodosum, or urticaria)

83
Q

What infectious agent is a cause of Tinea that is sometimes passed from kittens to humans?

A

Microsporum canis

84
Q

Name the four major causes of subcutaneous mycoses.

A

Sporotrichosis (follows trauma — rose handlers’ disease)

Eumycotic mycetoma (draining sinuses in tissues, fascia, and bone)

Chromoblastomycosis (‘cauliflower lesions’)

Phaeohyphomycosis

85
Q

What is the main thing to know regarding sporotrichosis?

A

It typically follows trauma — rose handlers’ disease

86
Q

What is the main thing to know regarding eumycotic mycetomas?

A

They present as swelling and draining sinuses in tissues, fascia, and bone

87
Q

What is the main thing to know regarding chromoblastomycosis?

A

It causes cauliflower-like lesions

T1 - Phase 2 - Systems Modules (I) (27 decks)

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