exotoxins Flashcards
G+ or G- produce exotoxins
Gram positives
inhibits ACh release, flaccid paralysis
botulinum
phospholipase that causes gas gangrene
clostridium alpha toxin
inhibits the inhibitor of adenylate cyclase -> whooping cough
pertussis toxin
stimulates adenylate cyclase -> chloride and water into gut, diarrhea
cholera and heat-labile ETEC
destroys leukocytes
s. aurues
hemolysis and panton-valentine leukoceidin
composed of edema factor, lethal factor, and protective antigen
anthracis
enterotoxin causing rice-water diarrhea
vibrio cholera, heat labile ETEC
causes scarlet fever
strep pyogenes
causes toxic shock syndrome
TSST-1 (s aureus)
inactivates EF-2 -> pseudomembranous pharyngitis
diptheria
inactivates EF-2 -> host cell death
exotoxin A from Pseudomonas
blocks the release of the inhibitory neurotransmitter glycine
tetanospasmin
corynebacterium diptheriae
diphtheria toxin (inactivates EF-2)
Pseudomonas
exotoxin A (inactivates EF-2 and causes cell death)
Shigella
shiga toxin (inactivates 60S ribosomes) GI mucosal damage -> dysentery, HUS
Enterohemorrhagic E. coli (o157:H7)
shiga-like toxin (inactivates 60S ribosome)
HUS and bloody diarrhea
ETEC
Heat-labile (overactivates adenylate cyclase -> increases Cl secretion)
heat-stable (overactivates guanylate cyclase -> decrease NaCL resorption)
both cause watery diarrhea
bacillus anthracis
edema factor (mimics adenylate cyclase) black eschar
vibrio cholerae
cholera toxin (overactivates adenylate cyclase by permanently activating Gs)
Bordatella pertussis
overactivates adenylate cyclase by disabling Gi
whooping cough
Clostridium tetani
tetanospasmin cleaves SNARE
prevents release of GABA and glycine
clostridium botulinum
botulinum toxins A-G cleave SNARE
flaccid paralysis prevents stimulatory ACh signals
clostridium perfringens
alpha toxin degrades tissue and cell membranes (phospholipase)
myenecrosis and hemolysis because of degradation of phospholipase C
streptococcus pyogenes
streptolysin O degrades cell membranes and lyses RBC
antibodies used to diagnose rheumatic fever
staphylococcus aureus
toxic shock syndrome toxin (TSST-1) acts as superantigen
streptococcus pyogenes
Exotoxin A acts as superantigen