Bacterial toxins

Question 1

Diptheria toxin

Answer 1

Cornyebacterium diptheriae; AB exotoxin that ribosylates and inactivates elongation factor (EF-2)

Question 2

Exotoxin A

Answer 2

Pseudomonas aeruginosa; Inactivates elongation factor (EF-2)

Question 3

<p>Shiga toxin</p>

Answer 3

<p>Shiga spp.; Inactivate 60S ribosome by removing adenine from rRNA --> HUS</p>

Question 4

Shiga-like toxin

Answer 4

EHEC - 0157:H7; Inactivate 60S ribosome by removing adenine from rRNA –> HUS

Question 5

<p>Heat-labile toxin</p>

Answer 5

<p>ETEC; Inc cAMP by permanently activating Gs --> Cl- secretion in gut and H20 efflux</p>

Question 6

Heat-stable toxin

Answer 6

ETEC; Inc cGMP –> dec resorption of NaCl and H20 in gut

Question 7

<p>Edema factor</p>

Answer 7

<p>Bacillus anthracis; Mimics the adenylate cycalse enzyme --> inc cAMP</p>

Question 8

Cholera toxin

Answer 8

Vibrio cholerae; Inc cAMP by permanently activating Gs –> Cl- secretion in gut and H20 efflux

Question 9

<p>Pertussis toxin</p>

Answer 9

<p>Bordetella pertussis; Inc cAMP by disabling Gi impairing phagocytosis to permit survival of microbe</p>

Question 10

Tetanospasmin

Answer 10

Clostridium tetani; Cleave SNARE protein required for neurotransmitter rel –> toxin prevents rel of inhibitory (GABA and glycine) neurotransmitters in spinal cord (mm rigidity and lock-jaw)

Question 11

<p>Botulinum toxin</p>

Answer 11

<p>Clostridium botulinum; Cleave SNARE protein required for neurotransmitter rel --> prevents rel of stimulatory (Ach) signals @ NMJ (flaccid paralysis)</p>

Question 12

Alpha toxin

Answer 12

Clostridium perfinigens; Phospholipase that degrades tissue and cell membranes (splits phospholipids) –> degradation of phospholipid C –> myonecrosis (gas gangrene) and hemolysis

Question 13

Streptolysin O

Answer 13

Steptococcus pyogenes (Group A strep); Protein that degrades cell membrane; Host Abs against toxin seen with ASO titer

Question 14

<p>TSST-1 (Toxic shock syndrome toxin)</p>

Answer 14

<p>S. aureus; MHC II binds tightly to TCR causing it to rel IFN-gamma, which inc rel of IL-1, IL-6, and TNF-alpha --> shock --> end-organ failure</p>

Question 15

Exotoxin A

Answer 15

Strep pyogenes (Group A strep); MHC II binds tightly to TCR causing it to rel IFN-gamma, which inc rel of IL-1, IL-6, and TNF-alpha –> shock –> end-organ failure; Causes scarlet fever

Question 16

Which 5 bacterial toxins encoded via lysogenic phase?

Answer 16

ABCDE: shigA-like toxin, Botulinum toxin, Cholera toxin, Diphtheria toxin, Erythrogenic toxin of strep pyogenes

Question 17

Clostridium toxin

Answer 17

Toxin A: attracts neutrophils causing mucosal inflammation, loss of water into the gut lumen, diarrhea, as well as mucosal death
Toxin B: the cytotoxin, causes actin depolymerization, loss of cellular cytoskeleton integrity, cell death, and mucosal necrosis