Bacterial Pathogenesis (Exam 1) Flashcards

1
Q

_______ is secreted by living bacteria with a specific activity against hos tissues.

A

exotoxin

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2
Q

_______ is inside a bacterial cell envelope and is released when it disintegrates or dies.

A

endotoxin

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3
Q

What are “superantigens”?

A

surface-acting exotoxins

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4
Q

Superantigens bypass normal antigen presentation binding _______ to stimulate _______.

A

MHC
T cells

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5
Q

Superantigens stimulate T cells which produces what major effect?

A

cytokine storm (excess IL-2 production)

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6
Q

(T/F) Superantigens have an effect at a systemic but not a local level.

A

False - can be either

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7
Q

Locally, superantigen effects are _______, while systemically, they lead to _______.

A

flesh-eating
toxic shock

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8
Q

A-B exotoxins have A which is the ______ subunit and B which is the ______ subunit.

A

active
binding

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9
Q

Direct, “door-to-door” delivery of toxins from a bacterial cytoplasm to a eukaryotic host uses what system?

A

Type III secretion system

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10
Q

_______ is reversible variation while ________ is irreversible variation in terms of rearrangements of major surface protein genes in bacteria.

A

phase variation
mutation

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11
Q

Term for small molecule secreted by pathogens which binds a host’s iron for import into bacteria.

A

siderophores

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12
Q

Lethal pathogens have a (low/high) LD50 and ID50.

A

low

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13
Q

LD50s are (higher/lower) than ID50s.

A

higher

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14
Q

Term for adherence factors of bacteria which help them stick to host ligands.

A

adhesins

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15
Q

What is an example of an adhesin on bacteria?

A

fimriae/pili

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16
Q

Term for molecule which help bacteria into a host cell.

A

invasins

17
Q

Term for molecule on bacteria that binds to a host receptor which allows bacteria to internalize into a host cell after a signaling cascade occurs.

A

internalin

18
Q

What is the name of the mechanism bacteria use to internalize into a host cell using internalin?

A

zipper mechanism

19
Q

List the 2 strategies pathogens use to evade a host’s immune system.

A
  1. form capsules, S-layers, biofilms
  2. antigen/phase variation
20
Q

Antigenic variation is a strategy used by pathogens to evade a host’s immune system which leads to (low/high) frequency mutations in (specific/random) genes.

A

high
specific

21
Q

Term for bacteria that can replicate both inside and outside a host cell.

A

facultative intracellular

22
Q

Term for bacteria that cannot replicate outside a host cell.

A

obligate intracellular

23
Q

(T/F) All intracellular bacteria replicate within the host cytoplasm.

A

False - cytoplasm or vacuoles

24
Q

List 4 ways a host defends itself against intracellular pathogens.

A
  1. ROS
  2. antimicrobial peptides
  3. apoptosis
  4. lysozyme
25
Q

What mechanism do intracellular pathogens use to evade host defenses which contain virulence factors for protection?

A

pathogenicity islands

26
Q

Two molecules hosts make that bind iron and prevent pathogens from acquiring it.

A

lactoferrin
transferrin

27
Q

Two membrane disrupting proteins pathogens have which can cause tissue damage to the host.

A

hemolysin
leukotoxin

28
Q

Hemolysin is a pore-forming toxin of _______ while leukotoxin is a pore-forming toxin of ______.

A

RBCs
WBCs