Exotoxins

Question 1

Corynebacterium diptheriae

Answer 1

Diphtheria toxin - inactivates EF2 (elongation factor)

Causes pharyngitis with pseudomembrane

Question 2

Pseudomonas aeruginosa

Answer 2

Exotoxin A - inactivates EF2 (elongation factor)

Causes host cell death

Question 3

Shigella

Answer 3

Shiga toxin - inactivates host (eukaryotes) 60S ribosome (removes adenosine from rRNA)
Invades host M cells in peyers patches
Can cause HUS

Question 4

Enterohemorrhagic E. coli (EHEC)

Answer 4

Shiga-like toxin - inactivates host (eukaryotes) 60S ribosome (removes adenosine from rRNA)
Does NOT invade host cells

Question 5

Enterotoxigenic E. coli (ETEC)

Answer 5

Heat labile - increases cAMP
Heat stable - increases cGMP
Either one causes watery diarrhea (traveler’s diarrhea)

Question 6

Yersinia enterocolitica

Answer 6

Heat stable toxin - increases cGMP

Watery diarrhea

Question 7

Bacillus anthracis

Answer 7

Edema toxin - increases cAMP

Makes the edematous borders of the black eschar of cutaneous anthrax

Question 8

Vibrio cholerae

Answer 8

Cholera toxin - increases cAMP
Permanently activates Gs to inclease Cl- and H2O secretion in the gut
Rice-water stools (copious diarrhea)

Question 9

Bordetella pertussis

Answer 9

Pertussis toxin - inhibits Gi -> increases cAMP

Inhibits phagocytosis

Question 10

Clostridium tetani

Answer 10

Tetanospasmin -cleave SNARE; inhibits release of inhibitory NTs GABA and glycine
Spastic paralysis (lock-jaw)

Question 11

Clostridium botulinum

Answer 11

Botulinum toxin - cleaves SNARE; prevents release of stimulatory Ach at NMJ
Flaccid paralysis

Question 12

Clostridium perfringens

Answer 12

Alpha toxin - phospholipase that degrades cell membranes and causes myonecrosis

Entertoxin - causes food poisoning from cooked food that’s been out too long

Question 13

Streptococcus pyogenes

Answer 13

Streptolysin O (ASO titers to check for recent infxn) - hemolysis
Streptolysin S - hemolysis
Streptococcal pyrogenic exotoxins A, B and C - rash adn fever of Scarlet fever

Question 14

Staphylococcus aureus

Answer 14

alpha-hemolysin - hemolysis
beta-hemolysis - hemolysis
gamma-hemolysin - hemolysis and leukocyte toxicity
delta-hemolysin - toxic to RBCs and other cells
Panton-Valentine leukocydin - responsible for the tissue destruction of MRSA infxn; affects macrophages adn PMNs
Enterotoxin - vomiting and diarrhea
TSST1 - toxic shock syndrome
Exfoliative toxin - staph scalded skin syndrome in newborns