Bacterial Toxin MOAs Flashcards
Bacillus anthracis (edema factor)
Mimics the adenylate cyclase enzyme (inc. Camp) – Responsible for endematous borders of black eschar in cutaneous anthrax
Bacillus anthracis (lethal factor)
Kills the cell – quoting micro notes.
Bordetella pertussis
Pertussis toxin: Inhibits Gi which increases cAMP. This impairs phagocytosis and allows for bugs survival
Clostridium botulinum
Inhibits Ach release by cleaving SNARE protein required for neurotransmitter release
Clostridium difficile (toxin A, toxin B)
Toxin A = binds the brush border of the gut
Toxin B = cytotoxin that destroys the cytoskeletal structure of enterocytes causing the pseudomembranous colitis
Clostridium perfringens (alpha toxin)
Phospholipase that degrades tissue and cell membranes
Clostridium tetani
Prevents release of inhibitory (GABA and glycine) NT in spinal cord. Does this by cleaving SNARE protein required for NT release
Corynebacterium diphtheriae
Inactivates elongation factor 2 (EF-2) – same MOA as P. aeruginosa
EHEC
Shiga-like toxin - Inactivates 60S ribosome by removing adenine from rRNA.
ETEC (heat-labile toxin)
“Labile in the Air and Stable on the Ground” –
Labile = increases cAMP which pumps Cl- into the gut
ETEC (heat-stable toxin)
“Labile in the Air and Stable on the Ground” –
Stable = increases cGMP
Lipopolysaccharide (endotoxin)
Outer cell membrane of gram negs. Induces TNF and IL-1 release
Pseudomonas aeruginosa
Inactivates elongation factor 2 (EF-2) – same MOA as C. diphtheriae
Shigella species
Inactivates 60S ribosome by removing adenine from rRNA. Can also cause cytokine release
Staphylococcus aureus (enterotoxin)
Rapid-onset food poisoning – Mast cells responsible for emesis
Staphylococcus aureus (exfoliative toxin)
Scalded skin syndrome – toxin acts as a protease causing peeling of the skin.
Staphylococcus aureus (TSST-1)
Two main VF that are superantigens: S. aureus’s TSST-1, and S. pyo’s Exotoxin A.
Brings MHCII and TCR together and causes release of IFN-gamma and IL-2 causing shock.
Streptococcus pyogenes (streptolysin O)
Causes the RBC hemolysis
Vibrio cholerae
Permanently activates Gs causing increase in cAMP and inc. Cl- secretion into the gut = rice water diarrhea
