FA Bugs with Exotoxins II

Question 1

MOA diphtheria toxin and exotoxin A

Answer 1

Inactivate EF-2

Question 2

MOA ST and SLT

Answer 2

INactivate 60 S ribosome by removing adenine from rRNA

Question 3

MOA ETEC heat-labile toxin (LT)

Answer 3

overactivates adenylate cyclase –> increased cAMP –> increased chloride secretion in gut and H2O effluxu

Question 4

MOA ETEC heat-stabile toxin (ST)

Answer 4

Overactivates guanylate cyclase –> increased cGMP –> decreased respiration of NaCl and H2O in gut

Question 5

What is the net effect of both heat-labile and heat-stabile toxin on the infected individual?

Answer 5

Watery diarrhea:
Labile in the Air (adenylate cyclase)
Stable on the Ground (guanylate cyclase)

Question 6

MOA Edema factor

Answer 6

mimics the adenylate cyclase enzyme –> inc. cAMP

Question 7

Edematous borders of black eschar

Answer 7

ANTHRAX

Question 8

Manifestation of edema factor

Answer 8

likely responsible for characteristic edematous borders of black eschar in cutaneous anthrax

Question 9

Voluminous “rice-water” diarrhea

Answer 9

Cholera

Question 10

MOA cholera toxin

Answer 10

Over activates adenylate cyclase (–> inc cAMP) by permanently activating Gs –> increased Cl- secretion in gut and H2O efflux

Question 11

MOA pertussi toxin

Answer 11

Overactivates adenylate cyclase (inc cAMP) by disabling Gi, impairing phagocytosis to permit survival of microbe

Question 12

Whooping cough bug

Answer 12

Bordetella pertussi

Question 13

Describe a whooping cough

Answer 13

Child coughs on expiration and whoops on inspiration; can cause 100-day cough in adults

Question 14

MOA tetanospamis and botulinum toxin

Answer 14

Cleave SNARE protein required for NT release

Question 15

Muscle rigidity and lock jaw

Answer 15

Tetanus

Question 16

Flaccid paralysis, floppy baby

Answer 16

Botulism

Question 17

What neurotransmitters are affected in tetanus?

Answer 17

toxin prevents release of INHIBITORY (GABA and glycine) NTs in spinal cord

Question 18

What neurotransmitters are affected in botulism?

Answer 18

Toxin prevents release of stimulatory (ACh) signals at NMJ –> flaccid paralysis

Question 19

MOA alpha toxin

Answer 19

Phospholipase that degrades tissue and cell membranes

Question 20

MOA streptolysin O

Answer 20

protein that degrades cell membrane

Question 21

MOA TSST-1 and exotoxin A (as superantigens)

Answer 21

Bring MHC II and TCR in proximity to outside of antigen binding site to cause overwhelming release of IFN-gamma and IL-2 –> shock

Question 22

What does alpha toxin do to the patient?

Answer 22

Degradation of phospholipid C –> myonecrosis (“gas gangrene”) and hemolysis (“double zone” of hemolysis on blood agar)

Question 23

What does streptolysin O do to the patient?

Answer 23

Lyses RBCs; contributes to beta hemolysis;

Question 24

How do you diagnosed rheumatic fever

Answer 24

Host antibodies against streptolysin O (ASO)

Question 25

TSST-1 effect on patient

Answer 25

Toxic shock syndrome: fever, rash, shock

Question 26

Staph aureus exfoliative toxin effect on patient

Answer 26

Scalded skin syndrome

Question 27

Staph aureus enterotoxin effect on patient

Answer 27

food poisoning

Question 28

Strep pyogenes exotoxin A effect on patient

Answer 28

Toxic shock syndrome: fever, rash, shock