Bacterial toxins Flashcards
Phospholipase that degrades tissue and cell membranes
Alpha toxin (Clostridium perfringens)
Protease that cleaves SNARE.
Prevents release of INHIBITORY neurotransmitters
Tetanospasmin (Clostridium tetani)
Binds to MHC-II and TCR outside of antigen-binding site resulting in overwhelming release of IL-1, IL-2, IFN-y, TNF-a
TSST-1 or Toxic shock syndrome toxin (S. aureus)
Exotoxin A (S. pyogenes)
Inactivate EF-2 resulting in host cell death
Exotoxin A (Pseudomonas)
Overactivates guanylate cyclase –> decreased resorption of NaCl and H2O in gut
Heat-stable toxin / ST (ETEC)
Overactivates adenylate cyclase –> disabling Gi –> impairs phagocytosis
Pertussis toxin (Bordatella pertussis)
Inactivate 60S ribosome by removing adenine from rRNA resulting in host cell invasion –> enhanced cytokine release –> HUS
Shiga-like toxin (EHEC, typically serotype O157:H7)
Inactivate 60S ribosome by removing adenine from rRNA resulting in host cell invasion –> enhanced cytokine release –> HUS and GI mucosal damage
Shiga toxin (Shigella)
Mimics adenylate cyclase enzyme –> inc. cAMP
Edema toxin (Bacillus anthracis)
Inactivate EF-2 resulting in pharyngitis with pseudomembranes in throat and severe lymphadenopathy
Diptheria toxin (Corynebacterium dephtheriae)
Protease that cleaves SNARE. Prevents release of stimulatory signals at NMJ
Botulinum toxin (Clostridium botulinum)
Overactivates adenylate cyclase by permanently activating Gs –> Increased Cl- secretion in gut and H2O efflux
Cholera toxin (Vibrio cholera)
Protein that degrades cell membranes, especially RBC
Streptolysin O (Strep pyogenes)
Overactivates adenylate cyclase –> Increased Cl- secretion in gut and H2O efflux
Heat-stable toxin (ETEC)
