Infectious Agents - SRS Flashcards

1
Q

What infectious agents are visible at the E.M. level?

A

Prions

Viruses

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2
Q

What infectious agents are visible at the Micro level?

A

Bacteria

Fungi

Parasites

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3
Q

What infectious agents are visible at gross level?

A

Fungi

Parasites

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4
Q

How do prions replicate?

A

Misfolded protein causes misfolding of neighboring proteins

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5
Q

How do viruses replicate?

A

Nucleic acid replication using host mechanisms

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6
Q

How do bacteria reproduce?

A

Binary fission

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7
Q

How do fungi reproduce?

A

Asexual budding’

Sexual mating (spores)

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8
Q

How do parasites reproduce?

A

Sexual

Asexual

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9
Q

What kind of cell wall do viruses have?

What do some viruses have?

A

Protein capsid

Host cell envelope

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10
Q

What are some components of the fungi cell wall?

A

Chitin

Ergesterol

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11
Q

Gram + bacteria have an inner membrane and…

A

thick peptidoglycan

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12
Q

Gram (-) bacteria has inner and outer cell membranes and…

A

Middle thin peptidoglycan layer

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13
Q

What viruses are obligate intracellular?

A

All

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14
Q

What are some examples of obligate intracellular bacteria?

(6 were bolded in the chart)

A
  1. Clamydia,
  2. rickettsia,
  3. coxiella,
  4. erlichiae,
  5. anaplasma
    1. some mycobacteria (M. leprae)
      2.
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15
Q

What is an example of an obligate intracellular fungi?

A

Pneumocystis

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16
Q

What are some examples of obligate intracellular parasites?

A

Plasmodia,

T. gondii,

C. parvum,

leishmania,

T. cruzi

(not bolded)

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17
Q

What domain do the following fall under?

Prions

Viruses

Bacteria

Fungi

Parasites

A

Prions - non-cellular

Viruses - non-cellular

Bacteria - bacteria

Fungi - eukaryota

Parasites - Eukaryota

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18
Q

Prions are not organisms but spread like an infectious agent, the misfolded protein causes misfolding of neighboring proteins. What isiform converts what normal protien into the infectious isoform?

A

PrPSc converts normal PrPC proteins into infectious isoform

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19
Q

When PrPSc converts normal PrPC proteins into infectious isoform, how do the abnormal proteins aggregate?

A

β-pleated sheet (amyloid)

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20
Q

Prions cause subacute (transmissable) spongioform encephalopathies. What are some example of this?

(4 bolded, 6 total)

A
  1. Kuru
  2. Creutzfeldt–Jakob disease
  3. Bovine spongioform encephalopathy - (variant Creutzfeldt–Jakob disease (vCJD))
  4. Scrapie
  5. Fatal familial insomnia
  6. Gerstmann-Straussler-Scheinker syndrome
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21
Q

How does one acquire Kuru?

A

Papua New Guinea via funerary cannibalism

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22
Q

How does one acquire Creutzfeldt–Jakob disease?

A

•human to human transmission via blood or tissue or inherited

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23
Q

What is variant Creutzfeldt–Jakob disease (vCJD)?

A

Bovine spongioform encephalopathy in humans

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24
Q

Where does Scrapie occur?

A

Prototype that occurs in sheep and goats

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25
Q

What are some normal flora of the skin?

A
  1. S. epidermides,
  2. S. aureus,
  3. corynebacteria,
  4. streptococci,
  5. propionobacteria,
  6. gram negative bacteria.
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26
Q

Name three normal flora of the nasopharynx.

A

S. aureus,

S. epidermides,

streptococci

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27
Q

What are some examples of oral cavity normal flora?

A
  1. streptococci,,
  2. neisseria,
  3. H. influenza,
  4. anaerobes (bacteriodes,prevotella, fusobacterium, actinomyces)
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28
Q

What are 4 example of normal vaginal flora?

A
  1. lactobacillus,
  2. streptococci,
  3. gram negative bacteria,
  4. candida
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29
Q

What are some normal flora of the colon?

A
  1. gram negative bacteria (E. coli),
  2. Enterococcus faecalis,
  3. anaerobes (bacteriodes, bifinobacterium, clostridium)
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30
Q

Why is hepatitis D an incomplete virus?

A

Does not have all the genetic material it needs for replication, needs some from another virus.

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31
Q

The major defense in skin is the epidermal barrier. What are four examples of how this barrier can fail?

A
  1. Mechanical defects (punctures, burns, ulcers)
  2. Needle sticks
  3. Arthropod and animal bites
  4. Direct penetration
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32
Q

What are the pathogens that take advantage of mechanical defects in the epidermal barrier (punctures, burns, ulcers)?

(3)

A
  1. S. aureus,
  2. Candida albicans,
  3. Pseudomonas aeuginosa
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33
Q

What is this sample of a prion disease referred to?

A

Bubbly looking things in cells cause tissue to look like a sponge.

Thus called spongioform encephalopathies

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34
Q

What are two common needle stick pathogens?

A

HIV

Hepatitis Virus

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35
Q

What are some examples of infectious agents that utilize animal and arthropod bites as an invasion route?

A
  1. Yellow fever,
  2. plague,
  3. Lyme disease,
  4. malaria, rabies
36
Q

What is an example of a pathogen that directly penetrates the epidermal barrier?

A

Schistosoma

37
Q

What are the major local defenses of the GI tract?

A
  1. Epithelial barrier
  2. Acidic secretions
  3. Bile and pancreatic enzymes
  4. Normal protective flora
38
Q

What are two types of infectious agents that attach to and proliferate on the GI epithelial barrier?

A

Vibrio Cholerae

Giardia

39
Q

What are three examples of infectious agents that have the capacity to attach to and invade the epithelial barrier?

A

Shigella

Salmonella

campylobacter

40
Q

How do poliovirus and some other pathogenic bacteria breach the GI tract epithelium?

A

Uptake through M (microfold cells)

41
Q

How do protozoa and helminthes overcome the acidic secretions of the GI tract?

A

Acid resitant cysts and eggs

42
Q

How do hepatitis A, rotavirus and norovirus overcome the bile and pancreatic enzymes present in the GI tract?

A

Resistant microbial external coats

43
Q

How does clostridium difficile take hold and run amok?

A

Overcomes normal flora after broad spectrum antibiotic use

44
Q

What are the defenses of the respiratory tract?

A

Mucociliary clearance

Resident alveolar macrophages

45
Q

How do influenza viruses overcome the mucociliary clearance defense of the respiratory tract?

A

Attachment and local proliferation

46
Q

What mechanism do the following use to overcome mucocliliary clearance?

  • H. influenza
  • M. pneumoniae
  • Bordatella pertussis
A

Ciliary paralysis by toxins

47
Q

How does M. Tuberculosis overcome resident macrophages?

A

Resistance to killing by phagocytes. More on this later I imagine

48
Q

What are the defense mechanisms of the urogenital tract?

A

Urination

Normal vaginal flora

Intact epidermal/epithelial barrier

49
Q

How does E. Coli overcome the urination defense mechanism of the UG tract?

A

Obstruction

Microbial attachment

Local proliferation

50
Q

How does Candida albicans overcome the normal vaginal flora?

A

Antibiotic use opens the flood gates here also.

51
Q

How does N. Gonnococcu overcome the intact epidermal/epithelial barrier?

A

Microbial attachment and local proliferation

52
Q

How do herpes viruses and syphilis overcome the intact epidermal/epithelial barrier?

A

Direct infection and local invasion

53
Q

How does HPV overcome the intact epidermal/epithelial barrier?

A

Local trauma

54
Q

What are the common pathogens seen in those with B cell defects?

A

Bacteria (specifically encapsulated)

Giardia

Some viruses

55
Q

What are people who have deficiencies in C1, 2, 4 more suceptible to?

A

Encapsulated bacteria (S. Pneumo)

56
Q

What are people who are deficient in C3 susceptible to?

A

Ecapsulated bacteria

57
Q

If I had a neutrophil dysfunction what would I be predisposed to getting?

A

S. Aureus

Gram neg. Bacteria

Fungi

58
Q

What would a toll-like receptor signaling defect render you susceptible to?

A

Bacteria, viruses, fungi, parasites (all but prions)

59
Q

What does a splenectomy render someone susceptible to?

A

Encapsulated bacteria

60
Q

A phagocytosis defect renders one susceptible to?

A

Encapsulated bacteria

61
Q

What type of inflammatory response do we have to Staphylococcal pneumonia?

A

Suppurative (purulent) Infection

62
Q

What type of immune response do we have to syphillis?

A

Mononuclear and granulomatous inflammation

63
Q

What type of inflammatory response do we have to HPV and herpes virus?

A

Cytopathic-cytoproliferative reactions

64
Q

What is the inflammatory response we hace to Clostridium perfringens and hepatitis B?

A

Tissue necrosis

65
Q

What kind of inflammatory response do we see for chronic hepatitis?

A

Chronic inflammation/scarring

66
Q

What inflammatory reaction do we see to mycobacterium avium and mucormycosis?

A

No reaction

67
Q

What are some examples of testing in microbiology?

A
  • Special stains for organisms
  • Cultures (bacteria, fungi, viruses)
  • Antibiotic sensitivities
  • Direct visualization (parasites)
  • Antigen detection
  • Molecular detection
  • Serology
68
Q

What would you want to use to visualize H. Pylori?

A

Silver stain

69
Q

What else is silver stain good for?

A

Fungi

Spirochetes

Pneumocystitis

70
Q

What are the stains we use for fungi?

A

Gram

H&E

Papanicolaou

Calcofluor

Silver

PAS

71
Q

What are three generally good stains for bacteria?

A

Gram

H&E

Papanicolaou

72
Q

What stains are good for mycobacteria?

A

Acid Fast

Auromine-rhodamine

73
Q

Mucicarmine stain or India ink would be used for?

A

•cryptococcus capsule

74
Q

What are three types of antibody/antigen detection methods?

A

Enzyme immunoassays

Direct fluorescent antibody

latex agglutination

75
Q

What is Enzyme immunoassay (EIAs) good for?

A

Giardia

Cryptosporidium

76
Q

What media do we use for cultures?

A

Enriched media, cells usually.

77
Q

What is sabouraud’s dextrose agar the preferred medium for?

A

Fungi

78
Q

What is chocolate agar?

A

Medium with lysed RBCs

79
Q

What is MacConkey’s Agar used for?

A

Gram negative bacteria

80
Q

What is the minimum inhibitory concentration?

A

Lowest concentration of an antimicrobial that will inhibit the visible growth of a microorganism after overnight incubation

81
Q

What are some pathogens you should suspect if you see this?

A

•Catalase (+) staphylococci, micrococci, listeria, Corynebacterium diphtheriae, Burkholderia cepacia, nocardia, enterobacteriaceae (citrobacter, E. coli, enterobacter, klebsiella, shigella, yersinia, proteus, salmonella, serratia), pseudomonas, M. tuberculosis, aspergillus, cryptococcus, and rhodococcus

82
Q

How do we differentiate staph from strep?

A

Staph is catalase (+)

83
Q

How do we differentiate S. Aureus against S. epidermides?

A

Coagulase

84
Q

What is a hemolysis test often used for?

A

Streptococci

85
Q

What are the types of results possible for hemolysis tests?

A
  • α = partial (green)
  • β = total
  • ȣ = no hemolysis