FA Bugs with Exotoxins II Flashcards Preview

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Flashcards in FA Bugs with Exotoxins II Deck (28):
1

MOA diphtheria toxin and exotoxin A

Inactivate EF-2

2

MOA ST and SLT

INactivate 60 S ribosome by removing adenine from rRNA

3

MOA ETEC heat-labile toxin (LT)

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

4

MOA ETEC heat-stabile toxin (ST)

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

5

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

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

6

MOA Edema factor

mimics the adenylate cyclase enzyme --> inc. cAMP

7

Edematous borders of black eschar

ANTHRAX

8

Manifestation of edema factor

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

9

Voluminous "rice-water" diarrhea

Cholera

10

MOA cholera toxin

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

11

MOA pertussi toxin

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

12

Whooping cough bug

Bordetella pertussi

13

Describe a whooping cough

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

14

MOA tetanospamis and botulinum toxin

Cleave SNARE protein required for NT release

15

Muscle rigidity and lock jaw

Tetanus

16

Flaccid paralysis, floppy baby

Botulism

17

What neurotransmitters are affected in tetanus?

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

18

What neurotransmitters are affected in botulism?

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

19

MOA alpha toxin

Phospholipase that degrades tissue and cell membranes

20

MOA streptolysin O

protein that degrades cell membrane

21

MOA TSST-1 and exotoxin A (as superantigens)

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

22

What does alpha toxin do to the patient?

Degradation of phospholipid C --> myonecrosis ("gas gangrene") and hemolysis ("double zone" of hemolysis on blood agar)

23

What does streptolysin O do to the patient?

Lyses RBCs; contributes to beta hemolysis;

24

How do you diagnosed rheumatic fever

Host antibodies against streptolysin O (ASO)

25

TSST-1 effect on patient

Toxic shock syndrome: fever, rash, shock

26

Staph aureus exfoliative toxin effect on patient

Scalded skin syndrome

27

Staph aureus enterotoxin effect on patient

food poisoning

28

Strep pyogenes exotoxin A effect on patient

Toxic shock syndrome: fever, rash, shock