Lecture 34 - Exotoxins and endotoxins Flashcards

1
Q

spores have what characteristics

a. divide quickly
b. highly resistant
c. surround bacterium
d. mostly in gram-negative

A

b. highly resistant

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2
Q

streaming NUCLEAR material is most commonly an antimicrobial product of which innate immune cell?

A

Neutrophil

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3
Q

exotoxins

A

secreted
gram +

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4
Q

lipoteichoic acid

A

gram + cell wall

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5
Q

endotoxins

A

= lipopolysaccharide
gram -

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6
Q

what are four bacterial toxin mechanisms

A
  1. cell lysis
  2. pore formation
  3. inhibition of protein synthesis
  4. hyperactivation
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7
Q

describe clostridial diseases

A
  • gram +, spore-forming, anaerobic
  • can be enterotoxic, histotoxic, or neurotoxic
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8
Q

C. perfringens

A
  • enterotoxin
  • present intestinally in all animals, disease is due to shift in environment
  • cannot diagnose by culture, need PCR of toxin
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9
Q

what is type A enterotoxin

A

most common
hemorrhagic or necrotizing GI

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10
Q

what is type D enterotoxin

A

damage to vessels resulting in fluid loss, edema, pulpy kidney disease, etc.

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11
Q

C. difficile

A

fatal diarrheal disease following broad-spectrum antibiotic tx

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12
Q

C. piliforme

A

hepatic necrosis by stress/immunosuppression

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13
Q

C. septicum

A

malignant edema/gas gangrene

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14
Q

what is the basic pattern of activated spore clostridia

A
  1. ingestion
  2. migration to tissues
  3. trauma causes an anaerobic environment
  4. Disease!!!
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15
Q

C. chauveoi

A

Blackleg
spores from intestine

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16
Q

C. haemolyticum

A

Bacillary hemoglobinuria
ingestion to the liver

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17
Q

C. novyi

A

black disease
ingestion to the liver and vascular damage

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18
Q

Actinobacillus pleuropneumoniae

A

swine disease
cytotoxins (endotoxin) which cause neutrophil and macrophage damage

19
Q

what are A and B in terms of bacterial mechanisms

A

A = active component
B = binding component

20
Q

summarize how bacillus anthracis uses A and B

A

spore is ingested and matures to B. anthracis which will bind toxic components outside the cell for endocytosis

21
Q

what prevents the release of GABA and causes spastic paralysis

A

Tetanus

22
Q

what prevents the release of ACh and produces flaccid paralysis

A

botulism

23
Q

A-domain has what job?
B-domain has what job?

A

A = cleave proteins within the target (SFC or SNARE)
B = mediate transport

24
Q

what is the importance of SNARE proteins

A

delivers neurotransmitters within a vesicle to the cell membrane

25
Q

clostridium botulinum

A

endospores ingested and undergo hematogenous spread; botulism symptoms

26
Q

summarize Clostridium tetani

A

entrance via wound to distal processes of neurons. enters neural-neural junction and binds inhibitory interneurons to prevent the release of GABA

27
Q

a secreted bacterial toxin is called an

A

exotoxin

28
Q

which bacterium causes cell membrane lysis

A

C. perfringens

29
Q

which bacterium causes disease through the activation of spores already in tissues

A

C. chauvoei

30
Q

which bacterium uses an A-B toxin system to cause disease

A

B. anthracis

31
Q

lipopolysaccharide is associated with which group of bacteria

A

gram -

32
Q

which pattern recognition receptor recognizes LPS

A

toll-like receptor

33
Q

which is not a pro-inflammatory cytokine

a. IL-1
b. IL-10
c. IFN-y
d. TNF-a

A

d. IL-10

34
Q

what happens first in acute inflammation

A

vasodilation

35
Q

describe endotoxin activity

A

gram -
lipid A is a toxic compound
targets TLR4 on macrophages
initiates cytokine cascade

36
Q

lipoteichoic acid has similar actions as ____ through ____

A

endotoxins; TLR2

37
Q

what is unique about LPS effects

A

most are indirect
induces nonspecific resistance to infection

38
Q

what is endotoxemia? what are the 3 factors that help perpetuate it?

A

increased circulating LPS

  1. increased gram - bacteria in gut
  2. increased gut permeability
  3. other gram - infections
39
Q

what is endotoxemia in horses

A

sepsis (cytokine storm to immune paralysis to organ failure)
increases laminitis risk

40
Q

what is endotoxin tolerance

A

prior exposure of monocytes/macrophages to low levels cause refractory to challenge with large amounts

41
Q

the toxic component of lipopolysaccharide is

A

lipid a

42
Q

LPS is recognized by

A

TLR4

43
Q

endotoxemia is defined as increased levels of LPS in the

A

blood