OphthLover

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In FA, it's stated that one of the major ways EHEC differs from Shigella is how it "does not invade host cells." I've also seen in explanation to one of the UWorld questions how Shigella differs from many other enteropathogenic organisms becuase it causes disease through "direct invasion of colonic mucosal cells."

But how does EHEC, without also "invading" mucosal cells, inhibit the protein synthesis taken place in the mucosal cells by removing adenine from rRNA of 60S ribosomal component? Is the way Shigella "invades" mucosal cells suppoed to be different from how EHEC enters musosal cells to have its effect on mucosal cell protein synthesis? Any help would be greatly appreciated.
 
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In FA, it's stated that one of the major ways EHEC differs from Shigella is how it "does not invade host cells." I've also seen in explanation to one of the UWorld questions how Shigella differs from many other enteropathogenic organisms becuase it causes disease through "direct invasion of colonic mucosal cells."

But how does EHEC, without also "invading" mucosal cells, inhibit the protein synthesis taken place in the mucosal cells by removing adenine from rRNA of 60S ribosomal component? Is the way Shigella "invades" mucosal cells suppoed to be different from how EHEC enters musosal cells to have its effect on mucosal cell protein synthesis? Any help would be greatly appreciated.
The toxin.
 
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Something I picked up on from Kaplan was that normally, bloody diarrhea is caused by invasive organisms (like Shigella & Campy) but EHEC is not invasive and can cause bloody diarrhea through the Shiga-like toxin (helloooo, the name says its LIKE SHIGELLA'S TOXIN!!) So even though Shigella invades the mucosa and can produce dysentery, they both release a toxin that does what you said binds to the 60s ribosomal subunit and inhibits protein synthesis. I also read somewhere that the exception is the EHEC strain O157:H7 which is invasive, but perhaps someone else can confirm this.
 
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Something I picked up on from Kaplan was that normally, bloody diarrhea is caused by invasive organisms (like Shigella & Campy) but EHEC is not invasive and can cause bloody diarrhea through the Shiga-like toxin (helloooo, the name says its LIKE SHIGELLA'S TOXIN!!) So even though Shigella invades the mucosa and can produce dysentery, they both release a toxin that does what you said binds to the 60s ribosomal subunit and inhibits protein synthesis. I also read somewhere that the exception is the EHEC strain O157:H7 which is invasive, but perhaps someone else can confirm this.
The only exception I know for O157 H7 is sorbitol fermentation.
 

Jabbed

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Something I picked up on from Kaplan was that normally, bloody diarrhea is caused by invasive organisms (like Shigella & Campy) but EHEC is not invasive and can cause bloody diarrhea through the Shiga-like toxin (helloooo, the name says its LIKE SHIGELLA'S TOXIN!!) So even though Shigella invades the mucosa and can produce dysentery, they both release a toxin that does what you said binds to the 60s ribosomal subunit and inhibits protein synthesis. I also read somewhere that the exception is the EHEC strain O157:H7 which is invasive, but perhaps someone else can confirm this.
Enteropathogenic E. coli (EPEC) is the invasive one if memory serves.
 

Entadus

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EHEC does not invade the mucosal cells. It does however produce "Shiga-like" toxin, which is an Exotoxin (secreted by the bacteria). The toxin is composed of one "A" subunit (confers the toxic Activity) and 5 "B" subunits (Binding to / ENTRY into the mucosal cells). So EHEC will produce cytotoxicity and necrosis without technically "invading".
 
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Phloston

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Shigella and EHEC have a toxin with the same MOA.

But EIEC invades, not EHEC.

Therefore, Shigella and EIEC invade.
 
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Phloston

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Only thing you need to know about EPEC is that it flattens intestinal villi.
 

Patau

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Phloston

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I do not know what that explanation was but some EHEC strains do invade (http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1087320/). Try not to confuse yourself. O157:H7 is a strain of EHEC that does not invade. Its the LEE component that makes the difference.
I like how you throw in the sentence 'try not to confuse yourself.' Thanks I'll be sure to take your advice on board. I'll be completely honest that this will cause you to over-think things.
 

Patau

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I like how you throw in the sentence 'try not to confuse yourself.' Thanks I'll be sure to take your advice on board. I'll be completely honest that this will cause you to over-think things.
I like how you think your reply is classy but it is really just passive-aggressive.
 
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Phloston

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I like how you think your reply is classy but it is really just passive-aggressive.
If you met me I'm very far from classy.
 

Patau

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On step 1 EHEC = 0157:H7.
Yah I agree. What I gathered from the OP was that he is not asking about what is on step 1, he was asking about the pathogenesis of invasion and why EHEC does not invade and why Shigella does. I am finding it hard to believe that there is more to medicine than what is tested on step 1, must be over thinking things...
 
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Yah I agree. What I gathered from the OP was that he is not asking about what is on step 1, he was asking about the pathogenesis of invasion and why EHEC does not invade and why Shigella does. I am finding it hard to believe that there is more to medicine than what is tested on step 1, must be over thinking things...
He has posted in Step 1 forum. I guess he is asking about things that is Step 1 relevant. Just my thought :shrug:Besides, OP is an ophthalmology lover. Anything poop-related would not be his priority:vomit:
 

Patau

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He has posted in Step 1 forum. I guess he is asking about things that is Step 1 relevant. Just my thought :shrug:Besides, OP is an ophthalmology lover. Anything poop-related would not be his priority:vomit:
This one's for @Phloston. I've always admired him and he's been very helpful. - you.old
Please get his steamin seamen truck out of your mouth. But it is cute that you want to defend him. Internet love is real.
 
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This one's for @Phloston. I've always admired him and he's been very helpful. - you.old
Please get his steamin seamen truck out of your mouth. But it is cute that you want to defend him. Internet love is real.
You've done a bit of research. Good good. I don't care what you say. But good luck for your prep.