Lecture 34 - Exotoxins and endotoxins

Question 1

spores have what characteristics

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

Answer 1

b. highly resistant

Question 2

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

Answer 2

Neutrophil

Question 3

exotoxins

Answer 3

secreted
gram +

Question 4

lipoteichoic acid

Answer 4

gram + cell wall

Question 5

endotoxins

Answer 5

= lipopolysaccharide
gram -

Question 6

what are four bacterial toxin mechanisms

Answer 6

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

Question 7

describe clostridial diseases

Answer 7

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

Question 8

C. perfringens

Answer 8

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

Question 9

what is type A enterotoxin

Answer 9

most common
hemorrhagic or necrotizing GI

Question 10

what is type D enterotoxin

Answer 10

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

Question 11

C. difficile

Answer 11

fatal diarrheal disease following broad-spectrum antibiotic tx

Question 12

C. piliforme

Answer 12

hepatic necrosis by stress/immunosuppression

Question 13

C. septicum

Answer 13

malignant edema/gas gangrene

Question 14

what is the basic pattern of activated spore clostridia

Answer 14

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

Question 15

C. chauveoi

Answer 15

Blackleg
spores from intestine

Question 16

C. haemolyticum

Answer 16

Bacillary hemoglobinuria
ingestion to the liver

Question 17

C. novyi

Answer 17

black disease
ingestion to the liver and vascular damage

Question 18

Actinobacillus pleuropneumoniae

Answer 18

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

Question 19

what are A and B in terms of bacterial mechanisms

Answer 19

A = active component
B = binding component

Question 20

summarize how bacillus anthracis uses A and B

Answer 20

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

Question 21

what prevents the release of GABA and causes spastic paralysis

Answer 21

Tetanus

Question 22

what prevents the release of ACh and produces flaccid paralysis

Answer 22

botulism

Question 23

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

Answer 23

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

Question 24

what is the importance of SNARE proteins

Answer 24

delivers neurotransmitters within a vesicle to the cell membrane

Question 25

clostridium botulinum

Answer 25

endospores ingested and undergo hematogenous spread; botulism symptoms

Question 26

summarize Clostridium tetani

Answer 26

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

Question 27

a secreted bacterial toxin is called an

Answer 27

exotoxin

Question 28

which bacterium causes cell membrane lysis

Answer 28

C. perfringens

Question 29

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

Answer 29

C. chauvoei

Question 30

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

Answer 30

B. anthracis

Question 31

lipopolysaccharide is associated with which group of bacteria

Answer 31

gram -

Question 32

which pattern recognition receptor recognizes LPS

Answer 32

toll-like receptor

Question 33

which is not a pro-inflammatory cytokine a. IL-1 b. IL-10 c. IFN-y d. TNF-a

Answer 33

d. IL-10

Question 34

what happens first in acute inflammation

Answer 34

vasodilation

Question 35

describe endotoxin activity

Answer 35

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

Question 36

lipoteichoic acid has similar actions as ____ through ____

Answer 36

endotoxins; TLR2

Question 37

what is unique about LPS effects

Answer 37

most are indirect induces nonspecific resistance to infection

Question 38

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

Answer 38

increased circulating LPS 1. increased gram - bacteria in gut 2. increased gut permeability 3. other gram - infections

Question 39

what is endotoxemia in horses

Answer 39

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

Question 40

what is endotoxin tolerance

Answer 40

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

Question 41

the toxic component of lipopolysaccharide is

Answer 41

lipid a

Question 42

LPS is recognized by

Answer 42

TLR4

Question 43

endotoxemia is defined as increased levels of LPS in the

Answer 43

blood