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Flashcards in Catalse + bugs and toxins Deck (45):
1

Which disease predisposes to infection with catalse + bugs?

Chronic granulomatous disease; lacking NADPH oxidase but bugs bring in H2O2 which is converted by MPO into free radicals so they can still kill bugs unless they produce catalase that breaks down H2O2

1

How can endotoxin cause DIC?

Activates tissue factor, which starts the coagulation cascade

1

Cholera toxin most similar to:

LT toxin of ETEC

Pertussis toxin

 

(Increase cAMP)

1

Streptolysin O most similar to:

Alpha toxin of C. perfringens

 

(Degrade cell membranes)

2

Describe the two different exotoxin A's

Pseudomonas exotoxin A = inhibits EF-2 = inhibits protein synthesis

 

GAS exotoxin A = superantigen = shock

3

What causes HUS seen in EHEC and Shigella toxin?

Shiga toxin causes release of cytokines that induce HUS

3

What 3 things does endotoxin activate?

Macrophages, complement, tissue factor/coagulation cascade

4

MOA tetanospasmin

Cleaves SNAREs = inhibit release of glycine and GABA from Renshaw cells in SC = spasticity, risus sardonicus, lockjaw

5

MOA pertussis toxin

Inactivates Gi = overactivity of cAMP = inhibits phagocytosis = permits survival of bug

5

MOA alpha toxin

Phospholipase = degrades cell membranes = myonecrosis + double zone of hemolysis on BAP

 

(C. perfringens)

6

Lysogenic phage-encoded toxins

Shiga toxin

Botulinum toxin

Cholera toxin

Diphtheria toxin

Erythrogenic toxin of GAS

7

Overactivates cAMP

LT of ETEC (directly)

Cholera toxin (by permanently activating Gs)

Pertussis toxin (by inactivating Gi)

8

Mechanism of action of Shiga-like toxin/Shiga toxin

Inhibits 60S ribosome by removing adenine from rRNA

9

MOA streptolysin O

Degrades cell membranes = lyses RBCs

10

Toxins that inhibit release of NT

Botulinum toxin

Tetanospasmin

11

MOA superantigens

Bind MHC class II and TCR within proximity of antigen binding site = activates many, many T cells = massive release of IF-gamma and IL-2

12

What do macrophages activated by LPS produce? Function of these products?

TNFalpha = hypotension, fever

IL-1 = fever

NO = hypotension

13

People with chronic granulomatous disease are suspectible to which specific bugs?

Pseudomonas, Listeria, Aspergillus, Candida, E. coli, S. aureus, Serratia

15

Toxin that inhibits phagocytic activity

Pertussis toxin

16

If a bacteria is known to inhibit 60S ribosomal subunit, how can you know which bacteria it is?

Must be Shigella or EHEC - Shigella invades, EHEC doesn't

17

Catalse + bugs

Pseudomonas, Listeria, Aspergillus, Candida, E. coli, S. aureus, Serratia

18

Mimics cAMP

Edema factor of anthrax

20

MOA LT

Overactivates cAMP = increased Cl- secretion into lumen = H20 follows = watery diarrhea

 

 

(ETEC)

20

Diphtheria toxin most similar to

Exotoxin A of Pseudomonas

22

Protein A vs. exotoxin A

Protein A is membrane-bound toxin of S. aureus that binds to the Fc region of IgG to inhibit complement

 

Exotoxin A from Pseudomonas inhibits EF-2 to inhibit protein synthesis OR superantigen of GAS

22

MOA botulinum toxin

Cleaves SNAREs = inhibits release of ACh at NMJ = flaccid paralysis

23

Causes beta-hemolysis on BAP

Streptolysin O of GAS

24

Superantigens causing shock

TSST-1 (S. aureus)

Exotoxin A (GAS)

26

Fever + rash + shock

Toxic shock = exotoxin A (GAS) or TSST-1 (S. aureus)

28

Mechanism of action of exotoxin A and diphtheria toxin

Inhibit EF2 = inhibit protein synthesis

29

Toxins that lyse cell membranes

Alpha toxin (C. perfringens)

Streptolysin O (GAS)

30

3 exotoxins that inhibits protein synthesis

Exotoxin A (P. aeruginosa)

Diphtheria toxin

Shiga toxin/Shiga-like toxin (Shigella/EHEC)

31

Toxin of scalded skin syndrome

Exfoliative toxin of S. aureus

33

Preformed exotoxin

S. aureus food poisoning (enterotoxin)

34

Two component toxins: A (attaches ADP-ribosylate to disrupt cell membrane) and B (binding and phagocytosis)

Toxins that inhibit protein synthesis = diphtheria toxin, Shiga toxin, exotoxin A

 

Cholera toxin

 

Pertussis toxin

 

LT of ETEC

35

MOA edema factor

MIMICS cAMP

 

(B. anthracis)

36

What is function of catalse?

Degrades H2O2 produced via NADPH oxidase reaction before it is converted into microbiocidal products via MPO

37

Generalized vs. specialized transduction

Generalized = lytic phage = phage infects bacterium and takes up some of its DNA, which it injects into another bacterium

 

Specialized = lysogenic phage = viral DNA incorporates into bacterial genome = viral DNA excised with flanking bacterial DNA = injected into another bacterium

38

MOA ST

Overactivates cGMP = decreased NaCl and H2O resorption = watery diarrhea

39

ASO

Anti-streptolysin O antibodies = diagnosis of rheumatic fever

 

(GAS)

40

Causes double zone of hemolysis on BAP

C. perfringens alpha toxin (PLase)

41

4 exotoxins that increase fluid secretion

Edema factor (anthrax)

ST and LT (ETEC)

Cholera toxin

42

Overactivated cGMP

ST of ETEC

44

Protease toxins

Botulinum toxin

Tetanospasmin

45

MOA Cholera toxin

Permanently activates Gs = overactive cAMP = Cl- and H2O efflux