Microbial Toxins

Question 1

Endotoxin

Answer 1

Lipid A of LPS on Gram - bacteria

Induces TNF, IL-1, IL-6, C3, C5, coagulation

Question 2

Exotoxin - Host tissue damage

Answer 2

Facilitate spread of bacteria in the hose by targeting ECM or necrotic debris
Includes hyalurinidase, collagenase, elastase, deoxyribonuclease, streptokinase

Question 3

Exotoxin - Damage to Cell Membrane

Answer 3

Pore formation –> cytolysis

Question 4

Exotoxin - Pyrogenic

Answer 4

Stimulates cytokine production

Scarlantinal & TSST-1

Question 5

Exotoxin - Diptheria Toxin

Answer 5

Irreversible Inhibition of Protein Synthesis
Targets heart and liver tissues
Two subunit protein - B allows for cellular entry and A acts as the toxin
Inactivates EF-2 by ribosylation

Question 6

Exotoxin - Pseudomonas aeringinosa exotoxin (PAE)

Answer 6

Irreversible Inhibition of Protein Synthesis
Targets the liver
Inactivates EF-2 by ribosylation

Question 7

Exotoxin - Shiga toxins

S. dysenterae, E. coli, and ricin

Answer 7

Irreversible Inhibition of Protein Synthesis

Inactivates ribosome via RNA N-glycosidases

Question 8

Exotoxin - Heat-Labile Enterotoxin

E. Coli, V. Cholera

Answer 8

Modifies Intracellular Signalling Pathway

Increases cAMP, increasing Chloride secretion –> watery diarrhea

Question 9

Exotoxin - Heat-Stable Enterotoxin

E. Coli

Answer 9

Modifies Intracellular Signalling Pathway

Increases cGMP –> watery diarrhea

Question 10

Exotoxin - Pertussis Toxin

B. pertussis

Answer 10

Modifies Intracellular Signalling Pathway
Increases cAMP –> tissue specific effects
(whooping cough)

Question 11

Exotoxin - Anthrax Edema Factor (EF)

B. anthracis

Answer 11

Modifies Intracellular Signalling Pathway
Increases cAMP (activated by calmodulin and Ca) --> watery efflux and edema

Question 12

Exotoxin - Anthrax Lethal Factor (LF)

Answer 12

Modifies Intracellular Signalling Pathway

Inhibits MAP kinase –> decreasing signal transduction –> cell death

Question 13

Exotoxin - Toxins A & B

C. defficile

Answer 13

Modifies Intracellular Signalling Pathway

glycosyl transferases that inhibit cytoskeletal growth

Question 14

Exotoxin - Botulinum Toxin

C. botulinum

Answer 14

Inhibits release of neurotransmitters

Cleaves SNARE protein –> inhibits vessicle transport –> inhibited release of Acetycholine from motor neurons

Question 15

Exotoxin - Tetanus Toxin

C. tetani

Answer 15

Inhibits release of neurotransmitters

Cleaves SNARE protein –> inhibits vessicle transport –> inhibited release of GABA/Glycine from inhibitory interneurons