Bacterial Toxins

Question 1

Diptheria toxin MOA

Answer 1

Inactivates elongation factor 2
Gene encoded by bacteriophage (virus that infects the bacteria)
Causes pharyngitis and pseudomembrane

Question 2

Pseudomonas toxin MOA

Answer 2

Exotoxin A
Inactivates elongation factor 2
Host cell death

Question 3

Shiga toxin MOA

Answer 3

Inactivates 60S Ribosome by removing adenosine from rRNA

Question 4

Shiga-like toxin MOA

Answer 4

Inactivates 60S Ribosome by removing adenosine from rRNA

Question 5

ETEC toxins

Answer 5

Heat labile toxin

Heat stabile toxin

Question 6

Heat labile toxin

Answer 6

ETEC 
overactivates adenylate cyclase 
Increased cAMP (labile in the Air) 
Increased Cl- secretion in gut and H20 loss
Watery diarrhea

Question 7

Heat stable toxin

Answer 7

ETEC overactivates guanylate cyclase
Increased cGMP (stable on the Ground)
Decreased resorption of NaCl and H20 in gut
Watery diarrhea

Question 8

Edema toxin

Answer 8

Bacillus antrhacis
Mimics adenylate cyclase enzyme
Increases cAMP

Question 9

Cholera toxin

Answer 9

Vibrio cholerae 
Overactivates adenylate cyclase 
Increases cAMP 
Permanently activates Gs 
Increased Cl secretion in gut causing H20 efflux

Question 10

Pertussis toxin

Answer 10

Bordetella pertussis 
Overactivates adenylate cyclase 
Increased cAMP 
Disables Gi 
Impaired phagocytosis permits survival of microbe

Question 11

Teanospasmin

Answer 11

Clostridium tetani
Protease that cleave SNARE require for NT release via vesicle fusion
Causes spasticity (lockjaw)
Prevents release of inhibitor GABA from Renshaw cells in spinal cord

Question 12

Botulinum toxin

Answer 12

Clostridium botulinum
Protease that cleaves SNARE required for NT release via vesicle fusion
Flaccid paralysis = floppy baby
Prevents release of stimulator ACh signals at presynaptic NMJ

Question 13

Heat stabile toxin

Answer 13

ETEC 
Yersinia enterocolitica 
Activates guanylyl cyclase
Increased cGMP 
Pseudoappendicits

Question 14

Alpha toxin

Answer 14

Clostriudium perfringes
Phospholipase lecithinase that degrades tissue and cell membranes
Myonecrosis = gas gangrene and hemolysis in double zone

Question 15

Streptolysin O

Answer 15

Strep pygoenes (Group A Strep)
Degrades cell membrane
Lyses RBCs contributes to Beta hemolysis
ASO titers used to dx rheumatic fever

Question 16

TSST-1

Answer 16

Staph aureus

Binds to MHC2 and TCR overwhelming release of IL-1, IL-2 and IFN-g and TNF-a = shock

Question 17

Exotoxin A

Answer 17

Strep pyogenes
(Group A Strep and S.Aureus)
Binds to MHC2 and TCR overwhelming release of IL-1, IL-2 and IFN-g and TNF-a = shock

Question 18

LPS

Answer 18

Endotoxin found endogenously in all gram negative bacteria 
Causes "ENDOTOXIN"
Edema via C3a 
NO
DIC/Death 
Outer membrane portion 
TNF-a = fever and hypotension 
O-antigen 
Xtremely heat stabile 
IL-1 = fever 
Neutrophil chemotaxis (via complement activation)

Question 19

Streptolysin O
Streptolysin S
Streptococcal pyrogenic exotoxins ABC
Erythrogenic toxins

Answer 19

S. pyogenes
O = hemolysis Oxygen labile
S = hemolysis Oxygen Stable
= Red rash and fever of scarlet fever

Question 20

a-hemolysin/toxin 
b-hemolysin
Sphingomyelinase C 
g-hemolysin 
d-hemolysin/toxin 
Panton Valentine leukocidin 
Enterotoxins 
TSST-1

Answer 20

S.aureus toxins

Question 21

Sphingomyelinase C causes

Answer 21

hemolysis

S.aureus

Question 22

g-hemolysin causes

Answer 22

leukocyte hemolysis

S.aureus

Question 23

d-hemolysin causes

Answer 23

RBC hemolysis

S.aureus

Question 24

Panton- Valentine leukocidin

Answer 24

Tissue destruction in MRSA
Both neutrophils and macrophages
S.aureus

Question 25

C.diff toxins

Answer 25

Toxin A enterotoxin binds to brush border of gut

Toxin B cytotoxin cuases cytoskeletal disruption via actin depolymerization leading to pseudomembranous colitis