Most Important Virulence Factors

Question 1

Acute glomerulonephritis

Answer 1

M protein:

mimicry of basement membrane s/p strep pyo infection

Question 2

Anthrax

Answer 2

Edema Factor:

Mimics cAMP

Question 3

Botulism

Answer 3

Botulinum toxin:

Cleaves SNARE, which is required for NT release; Prevents release of stimulatory signal (ACH)

Question 4

Cholera

Answer 4

Cholera toxin:

Activates Gs–> increase cAMP –> increase Cl and H2O efflux

Question 5

Diphtheria

Answer 5

Diphtheria toxin:

Inactivate elongation factor

Question 6

Escherichia coli meningitis

Answer 6

K capsule:

Crosses BBB

Question 7

Escherichia coli UTI

Answer 7

Pili/fimbriae:

Borrows into bladder wall

Question 8

Gas gangrene

Answer 8

LOS:
Inflammatory response, activates complement, then lyses phagosomes and that is what creates the purulent discharge. activation of inflammatory resposne = majority of sx

Question 9

Gram-negative septic shock

Answer 9

LPS:

Free LPS binds protein–> activates monocytes–> CD14; signalling via TLR; fever cytokines released

Question 10

Hemolytic uremic syndrome

Answer 10

EHEK Shiga-Like:

Inactivate 60s ribosome by removing adenine from rRNA

Question 11

Kidney stones

Answer 11

Ureases+:

Proteus bugs

Question 12

Klebsiella pneumoniae pneumonia

Answer 12

Polysacchraide capsule:
Resists complement mediated killing; resistance to phagocytosis; stops the amt of C3 placed on the bacteria so limits opsinization

Question 13

Listeriosis

Answer 13

Listeriolysin O:

Hemolysin; lysing the phagolysosome

Question 14

Meningococcal meningitis

Answer 14

Neisseria; polysaccharide capsule:

Avoid host phagocytosis

Question 15

Meningococcal septic shock

Answer 15

LOS Neisseria:

Endotoxin; destroys rbc

Question 16

Pneumococcal pneumonia/meningitis

Answer 16

Polysaccharide capsule:

Avoid host phagocytosis

Question 17

Peptic ulcers

Answer 17

Cytotoxin assoc gene (CAGa):

H pylori

Question 18

Pseudomembranous colitis

Answer 18

Toxin B (cytotoxin):
Cytoskeletal disruption via ACTIN DEPOLYMERIAZATION

Question 19

Pseudomonal pneumonia

Answer 19

Biofilm:

Assoc with Cystic fibrosis

Question 20

Pseudomonal wound infection

Answer 20

Exotoxin A:

Inactivates EF-2

Question 21

Rheumatic fever

Answer 21

M protein:

Molecular mimicry

Question 22

Scalded skin syndrome

Answer 22

Exfoliative toxin (s. aureus): Hydrolyzes proteins on the skin–> peeling

Question 23

Scarlet fever

Answer 23

Pyrogenic erythrogenic:

SPE: damage plasma membrane of blood capillaries

Question 24

Shigellosis

Answer 24

Shiga Toxin (ST):
Inactivate 60s ribosome by removing adenine from rRNA

Question 25

Staphylococcal food poisoning

Answer 25

Enterotoxin B:

Heat stable; superantigen leads to increase in cytokines;

Question 26

Strep throat

Answer 26

Streptolysin O

Question 27

Tetanus

Answer 27

Tetanospasmin:

Cleave SNARE, which is required for NT release; prevents release of inhibitory (GABA)

Question 28

Toxic shock syndrome

Answer 28

TSST (s.aureus)/Exotoxin S.pyo: Brings MHC II and TCR into proximity outsside the binding grove–> cytokine storm (inf gamm. IL2)

Question 29

Traveler’s diarrhea

Answer 29

Heat labile, heat stable: ETEC
o Heat-Labile (LT): overactivates adenylate cyclase (cAMP) –> increase Cl secretion in gut and H20 efflux
o Heat-Stable (ST): overactivates guanylate cyclase (cGMP) –> decrease resorption of NaCl and H20 in the gut

Question 30

Tuberculosis

Answer 30

Cord factor:

Inhibits macrophage maturation and induces release of TNFa

Question 31

Whooping cough

Answer 31

Pertussis :

Disables Gi –> increase in cAMP; impairs phagocytosis