Bacterial Toxin MOAs

Question 1

Bacillus anthracis (edema factor)

Answer 1

Mimics the adenylate cyclase enzyme (inc. Camp) – Responsible for endematous borders of black eschar in cutaneous anthrax

Question 2

Bacillus anthracis (lethal factor)

Answer 2

Kills the cell – quoting micro notes.

Question 3

Bordetella pertussis

Answer 3

Pertussis toxin: Inhibits Gi which increases cAMP. This impairs phagocytosis and allows for bugs survival

Question 4

Clostridium botulinum

Answer 4

Inhibits Ach release by cleaving SNARE protein required for neurotransmitter release

Question 5

Clostridium difficile (toxin A, toxin B)

Answer 5

Toxin A = binds the brush border of the gut

Toxin B = cytotoxin that destroys the cytoskeletal structure of enterocytes causing the pseudomembranous colitis

Question 6

Clostridium perfringens (alpha toxin)

Answer 6

Phospholipase that degrades tissue and cell membranes

Question 7

Clostridium tetani

Answer 7

Prevents release of inhibitory (GABA and glycine) NT in spinal cord. Does this by cleaving SNARE protein required for NT release

Question 8

Corynebacterium diphtheriae

Answer 8

Inactivates elongation factor 2 (EF-2) – same MOA as P. aeruginosa

Question 9

EHEC

Answer 9

Shiga-like toxin - Inactivates 60S ribosome by removing adenine from rRNA.

Question 10

ETEC (heat-labile toxin)

Answer 10

“Labile in the Air and Stable on the Ground” –

Labile = increases cAMP which pumps Cl- into the gut

Question 11

ETEC (heat-stable toxin)

Answer 11

“Labile in the Air and Stable on the Ground” –

Stable = increases cGMP

Question 12

Lipopolysaccharide (endotoxin)

Answer 12

Outer cell membrane of gram negs. Induces TNF and IL-1 release

Question 13

Pseudomonas aeruginosa

Answer 13

Inactivates elongation factor 2 (EF-2) – same MOA as C. diphtheriae

Question 14

Shigella species

Answer 14

Inactivates 60S ribosome by removing adenine from rRNA. Can also cause cytokine release

Question 15

Staphylococcus aureus (enterotoxin)

Answer 15

Rapid-onset food poisoning – Mast cells responsible for emesis

Question 16

Staphylococcus aureus (exfoliative toxin)

Answer 16

Scalded skin syndrome – toxin acts as a protease causing peeling of the skin.

Question 17

Staphylococcus aureus (TSST-1)

Answer 17

Two main VF that are superantigens: S. aureus’s TSST-1, and S. pyo’s Exotoxin A.

Brings MHCII and TCR together and causes release of IFN-gamma and IL-2 causing shock.

Question 18

Streptococcus pyogenes (streptolysin O)

Answer 18

Causes the RBC hemolysis

Question 19

Vibrio cholerae

Answer 19

Permanently activates Gs causing increase in cAMP and inc. Cl- secretion into the gut = rice water diarrhea