Okay, so poo + wounds = not good. In the Vietnam war sharpened sticks smeared with feces were used as a weapon. But people having, ah, toilet troubles will sometimes bleed from the sewage pipe, with no noticable symptoms of death. How does this work?
I wish I knew. I just wanted to say that “no noticeable symptoms of death” is my new favorite phrase.
My WAG is that the antibodies in that part of the body are very familiar with feces germs and are experienced at clobbering them. The problem is when feces germs get into OTHER parts of the body.
It’s not entirely clear. Antibodies, being created by blood cells, tend to move freely throughout the body, so you don’t really have (at least blood-borne) antibodies segregating to different parts of the body. You do have mucosal antibodies that may be participating, but, as I said, it’s not really clear.
Regarding the antibodies: There may be a slight difference between the antigens of your own intestinal flora and the antigens of another person’s (or species’) intestinal flora.
Just a WAG, tho’
It’s a bit of a mystery. Somehow the immune system is really on guard in a few places where bacteria are likely to enter the blood stream. Your mouth is another area where lots of bacteria are likely to enter the bloodstream through ordinary scrapes (from eating or brushing your teeth), and yet serious oral infections are surprisingly rare.
I don’t know if that’s the whole answer, but you have a high level of immunity to your own fecal bacteria. Also, those bacteria may be more dangerous ingested than from gaining a little access to your blood supply. And like most bacterial infections, the number of bacteria absorbed makes a difference. The world is full of bacteria that you ingest all the time without problems because there aren’t enough bacteria to overwhelm your immune response.
Everyone is, not inappropriately, emphasizing antibody protection at this site. That being said, however, the rectum is a classic example of an area where neutrophil defenses, and not antibodies, are key. In fact, people with low numbers of neutrophils (such as those on chemotherapy or with leukemia) may spontaneously develop invasive bacterial infections in the rectum, mouth, etc. In fact, they can even develop infection at other sites in the large intestine such as in the cecum. This is called typhlitis.
By the way, all of us, every day, have bacteria entering our bloodstream. This occurs, for example, with teeth brushing, chewing food, and having a bowel movement. As mentioned, the number of bacteria entering and then circulating in this way is a key determinant of whether infection will occur.
The observation that bacteria in the blood is ubiquitous, or at least, unavoidable, underlies the new recommendations to prevent bacterial infection of the heart valves in those whose valves are scarred. It used to be recommended that people with that condition take antibiotics when they had dental work (since such work permits bacteria to enter the bloodstream and presumably land on the damaged heart valve and then begin to cause infection there). With that logic, though, they should also be taking them whenever they crap. Bottom line nowadays is that antibiotic prophylaxis against heart valve infection is no longer recommended for dental wok (in most situations).
It would be a great name here on the boards.
sigh
I’m gonna regret this, I just know it.
Why does pooping introduce bacteria into the bloodstream? I’ve read this before - not sure if it was anywhere outside these boards, though - and I still don’t understand. Unless your stool contains broken glass or something, it shouldn’t be causing any rips or tears, right?
I’m thinking that if you have positive pressure on a fluid system, it’s harder for contamination to enter. Your blood pressure pushes the debris away, for the most part.
There may be not be any overt rips or tears but there is going to be, for lack of a better term, “micro-trauma”. By that I mean there will be some damage to the lining of the intestine by stool as it passes over it. Obviously (I think), this is more likely to happen when the stool is hard. And, as mentioned, when you bear down to poop, the pressure so created will tend to press the intestine wall tightly against the stool (at some points, at least). This may lead to damage to the integrity of the lining of the intestine and, as a result, the entry of bacteria into the bloodstream. In addition, the pressure would also work to drive stool contents into, and between, the cells of the intestine (on a microscopic level). This, again, would favour the development of bacteremia (bacteria in the blood).
To some extent this is correct, but it’s not the major cause.
As Karl Gauss mentions, bacteremia is common, even with ordinary defecation. At a microscopic level, even a bowel movement (or brushing your teeth, as is also mentioned above) causes some bacteria to enter the bloodstream.
There are two main reasons we don’t get septic and die–or at least have noticeable symptoms of impending doom.
The first, mentioned above, is that the body has defenses made to clear bacteria. This is a combination of various molecules such as immunoglobulins and certain chemicals (along with stuff like an elevated temperature which may make it harder for the germs to multiply), and also cells which attach to and scarf up the bugs.
There’s a second reason, not mentioned so far except indirectly by KarlGauss. The lining of the vasculature is slippery. It’s hard for bugs that enter the bloodstream to get a foothold anywhere, and without a foothold they are much more exposed to our host defenses. Bacteremia is most dangerous when the host has a defective endothelium somewhere and the bugs get a foothold. Think Teflon-coated pipes with a piece where the Teflon is chipped away that snags particles and you’ll get a rough idea. Germs like to find tiny crevices, get in there and hide from host defenses, and multiply in their little protected niche.
This is why some people are at risk for endocarditis–an infection of the lining of the heart, typically associated with a roughened lining of a valve that is defective for some reason. But it’s also why bacteremia produces abscesses in other areas–the brain, say, or bone–or foreign material such as a mesh or an artificial joint put in at surgery.
There is a crude correlation between the volume of bacteria trucking around and the risk for overwhelming the host defenses, so it’s not a perfect defense mechanism, and your point about the positive pressure of blood pushing away–cleansing the break in integrity, so to speak–might have a little validity.
As I’ve said many times on this board, we need to stop teaching the germ theory of disease as if that’s the primary mechanism by which we stay healthy. That’s led to way to much Clorox (including at the Pedant’s house). It’s really our host defenses that are the primary reason we stay free of infectious diseases. Take away those defenses and the patient checks out from even the feeblest of germs.
GALT (Gut-associated Lymphoid Tissue) is the main protector from unwanted pathogens of the gastrointestinal tract ie rectum, sigmoid colon, large & small intestine etc etc…
Basically a collection of immune cells in small mucosal folds you find along the intestines. Cells called M cells make sure that all potentially dangerous pathogens gets recognized and that antibodies are produced against them. Ready to attack if OP scenario was to happen.
The GALT also keeps virus and bacteria from adhering to the intestinal walls (epithelium), so they cant past the barrier and potentially cause an infection.
As mentioned above, certain people with immune deficiencies run much higher of infection from small tears in the intestine.
But still, take it easy next time you go wild on the shitter
I forgot to mention that most of the drainage from the GI tract, and therefore the bugs that sneak in via the gut, goes to the liver via the portal vein. The liver contains a lot of reticuloendothelial cells such as the Kupffer phagocytes, and is particularly suited to clean out debris and pathogens.
It’s still a good idea to keep your stools large and soft, but that’s another story for a different thread.
I think I may have half paraphrased Dave Barry, but I’m not sure.
I suffered rectal/anal fissures when I was about 3-5 or something. If my worst childhood memories are accurate, the doctors cauterized (genuinely not sure if that’s how it went or not… I should ask mom, since she’s the nurse). I also have some of the various gastro problems that pervade my father’s side of the family, and yes, there can be “rips or tears” (either from the TP or the… “stuff” being expelled - what can I say… I like spicy food…). 
And before anyone makes any silent or spoken allegations - no there was no ass abuse going on.
Hell, maybe I’m lucky… maybe fear of horrible “pains in the butt” made me subconsciously decide to be heterosexual (no offense to any homosexuals… it’s just that ass-land is off limits to anyone but the Charmin Bear… or the soap that I leave for guests to wash their hands with at parties).