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11 Cards in this Set
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Clostridium and Bacillus - what do they look like and what's their major type of pathogenesis. also, what about their air likes/dislikes?
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they're the two spore-forming rods.
they are differentiated based on their oxygen tolerance. bascillus is aerobic, while clostridium is anerobic. they principally use exotoxins. |
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what disease states can be caused by clostridium?
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gas gangrene, tetanus, botulism, and membranous colitis.
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what are the kinds of clostridium botulism pathologies possible? what's botulism toxin and how does it work?
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food borne, infant, and wound.
remember that clostridium botulinium grows only in anerobic environments. when it grows, it produces the toxin. toxin interferes with Ach, especially at muscle end plates - so you end up with flaccid paralysis. It's an AB toxin. Kills SNAP/SNARE proteins in the presynaptic vessicle, preventing release of the neurotransmitter. |
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describe how you get the 3 kinds of botulism - which is most common in US?
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food borne - can something, not hot enough to kill spores, aerobic environment = grow and die from preformed toxin, not infection.
infant - without normal flora, possible to become colonized by spores especially on honey. they slowly release the toxin - first have constipation, then get flaccid baby syndrome. wound - if deep puncture, local anerobic environment grows and you get toxin produced. no GI symptoms first. BABY BOTULISM is most common in united states. |
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Tetanus - what's the general way people get this and what common things lead to it?
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here, it's not a pre-formed toxin - you have to be colonized. but disease comes from the toxin, not the colonization.
usually deep penetrating wound. but can be on umbillical stump, post-abortion, and injection sites for druggies. need an anerobic environment. |
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how does tetanus toxin work?
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also messes with SNARE/SNAP proteins at the presynaptic vessicle, but this time it's blocking the release of INHIBITORY neurotransmitters (gaba/glycine).
so AFFERENT impulses come in and the signal gets blocked. rigid paralysis. |
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why is there a tetanus vaccine? if you get tetanus, do you need a vaccine?
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only a single serotype of the toxin, easy to prevent.
even if you get tetanus, you still need to get vaccinated - if you survived, you didn't have a lot of bacteria to begin with, and you don't make enough antibodies to stop a future invasion. everybody needs to get vaccinated. |
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what are the four clostridiums to know about and what are their major diseases?
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clostridium botulinium (botulism)
clostridium tetani (tetanus) clostridium perfinges (gas gangrene) clostridium dificil (diarrhea/pseudomembraous colitis) |
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what can clostridium perfinges cause and how can you get it? how can you treat it?
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can live in the bowel - so "perf"ing the bowel can cause "perf"inges.
also, this is where gas gangrene comes from - deep puncture wounds, gas produced, more anerobic environment, keeps spreading. if gas gangrene, need surgical debriedment and antibiotics. also, hyperbaric oxygen can kill these anerobes. note that perfinges can also cause toxin-mediate diarrhea. |
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clostridium dificil - what's up with this one?
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this is likely to be encountered. normal flora, but when you use antibiotics, it can take over. cause DIARRHEA AND PseudoMembranous COLITIS.
called "antibiotic diarrhea" |
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compare and contrast all our known toxins so far:
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cholera toxin = LT in ETEC. ADP-ribosylation of Gs(alpha), keep GTP, up cAMP
diptheria toxin = Pseudomonas Aeruginosa Toixin called Exotoxin A. Also ADP ribosylation, this time of EF-2, stop protein synthesis. Shiga toxin - in EHEC and shigella. Binds 28s rRNA, 60s ribosome and stops protein synthesis. Botulism toxin - stops Ach release from presynaptic PERIPHERAL muscles by messing with SNAP/SNARES, = flaccid paralysis. Tetatnus toxin = same mechanism, CENTRAL, messing with afferent signaling, stops release of inhibitory neurotransmitters = TETANY. |
