I know it's a stupid question but it is something i wonder. as the pH of the stomach is very low, it would seem unlikely that most bacterias should survive to it, and move to the intestines. especially bacterias with no special mechanism of survival like the lactobacilli found in many healthy drinks. do we drink those just to make poo, or do they actually have a roll in preventing intestinal diseases?
do bacterias survive going through the stomach?
- Thread starter Varda
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You are quite correct in the assumption that the stomach acid will indeed kill a lot of microorganisms. There are however acid resistant bacteria. This includes most lactobacilli. Several strains are known to survive and even propagate (e.g. Lactobacillus fermentum) in stomachs.
Another well known stomach bacterium is Helicobacter pylori, a causative agent of ulcer.
Another well known stomach bacterium is Helicobacter pylori, a causative agent of ulcer.
Varda said:
Actually, there's a quite a surprising number of them in the lower GI tract. And most are an aid to digestion. And guess how they got there.
In fact, as a result of taking heavy doses of antibiotics their numbers can be reduced to a dangerously low level. It can take quite while for them to recover.
There are whole colonies of them living in your guts! I have heard that HALF the weight of your solid waste is composed of bacteria.
It's not a stupid question at all! It's a really good question.Varda said:
I see that everyone, for the most part, is mentioning all the bacteria that reside in the intestines, but this isn’t the original question. The question is how they manage to pass through the extremely acidic environment of the stomach into the intestines.
As has been mentioned above, the acidic stomach is colonized by the hardy and enterprising bacterium Helicobacter pylori. This bacterium has an amazing set of features that it uses to live in this harsh environment, but I won't go into those now because you are talking about bacteria that pass through the stomach to the intestines.
The stomach is filled with acid (average pH ~2) and anti-microbial enzymes/peptides. As you say, it seems unlikely that any bacteria would survive it, and indeed this extreme environment is lethal to almost all bacteria ingested in food. But clearly some bacteria must make it through the stomach to the intestines otherwise there would not be any in there and there would be no such thing as bacterial food poisoning.
I don't have definitive answers to your questions. Perhaps someone with more specific GI tract knowledge will comment. But I can make these speculations......
(i) With bacteria, it's always a numbers game. Bacteria are successful because they can increase their numbers exponentially. As I said, the stomach is lethal to almost all bacteria ingested in food. If the starting numbers are low, then perhaps none make it through. But if starting numbers are high (such as in spoiled food, or deliberately such as in yoghurt or health drinks) then enough of the bacteria make it through to establish themselves in the intestines. If it’s “good bacteria” from yoghurt or a health drink, then that’s good. If it’s “bad bacteria” then that may lead to a GI tract infection.
(ii) Some bacterial species have an excellent defense mechanism against sudden hostile environmental conditions – they can sporulate. When bacteria form spores the cells secrete a thick and impermeable outer coat and shut down their metabolism to conserve resources and minimize internal damage. Bacterial spores are so hardy they can withstand acids, bases, chemicals, heat, cold, radiation, desiccation, vacuum and more for extended periods of time. Interestingly, Bacillus species are capable of sporulation. Bacillus species constitute a number of natural flora species. Perhaps the passage of this genus of bacterium trough the stomach is facilitated by their ability to form protective spores during their exposure to stomach acid.<P>
The colonisation of the intestines by bacterials espores seems very viable , but i dont think the large quantities of organisms would be enough to make them pass, as the gastric fluids brake down the molecules to nearly elemental units. Or am i wrong
but based on that, would you say that all bacterias in the intestines are cabable of esporulating? What about the protozoa and other types of parasitic microrganisms that are not capable of forming espores, how do they get there? :S
btw, some kinds of food poisonings can happen without the presence of the bacteria... these are the ones caused by exotoxines left in the extract
, but i dont think the large quantities of organisms would be enough to make them pass, as the gastric fluids brake down the molecules to nearly elemental units. Or am i wrong but based on that, would you say that all bacterias in the intestines are cabable of esporulating? What about the protozoa and other types of parasitic microrganisms that are not capable of forming espores, how do they get there? :S
btw, some kinds of food poisonings can happen without the presence of the bacteria... these are the ones caused by exotoxines left in the extract
Fraggle Rocker
Staff member
The most common bacteria culture in American yogurt is Lactobacillus acidophilus: "Milk bacteria that loves acid." L. bulgaricus and all the other yogurt cultures do just fine in acidic environments as well.
"Sour" is just an old word for "acidic." Yogurt is sour milk, milk made acidic by Lactobacillus bacteria. If the bacterial culture in your intestines has been destroyed by antibiotics, a quick way to replenish it is to eat yogurt until a balance of the more natural bacteria is restored.
Escheria coli, a common bacteria in stool, also survives an acidic environment. The most common cause of food poisoning is the ingestion of E. coli. (We Americans conspire to refer to the quick-in-and-out symptoms of E. coli poisoning as "stomach flu" or "24-hour flu" to perpetuate the fiction that there are no germs in American kitchens.)
Every organism has its limits. Canine saliva is much more acidic than human. (I can't find the pH number easily.) Dogs can eat things that are so bacteria-infested that just looking at it makes us sick, and their saliva disinfects it. Still, dogs can eat yogurt--and even the E. Coli in feces--to reestablish the bacteria culture in their intestines. Some bacteria are very tolerant of acid.
"Sour" is just an old word for "acidic." Yogurt is sour milk, milk made acidic by Lactobacillus bacteria. If the bacterial culture in your intestines has been destroyed by antibiotics, a quick way to replenish it is to eat yogurt until a balance of the more natural bacteria is restored.
Escheria coli, a common bacteria in stool, also survives an acidic environment. The most common cause of food poisoning is the ingestion of E. coli. (We Americans conspire to refer to the quick-in-and-out symptoms of E. coli poisoning as "stomach flu" or "24-hour flu" to perpetuate the fiction that there are no germs in American kitchens.
)Every organism has its limits. Canine saliva is much more acidic than human. (I can't find the pH number easily.) Dogs can eat things that are so bacteria-infested that just looking at it makes us sick, and their saliva disinfects it. Still, dogs can eat yogurt--and even the E. Coli in feces--to reestablish the bacteria culture in their intestines. Some bacteria are very tolerant of acid.
cyber_indian
Registered Senior Member
Consider this ... if you could count your body cells and multiply it by 10x - that's the count of bacteria living on and inside of you. I'll give you an example - farting is a result of a bacteria living in your intestines. And the most common as said earlier is the E. Coli. And also E. Coli is not the reason you get sick, but sometimes a host to hostile bacteria. Also the good bacteria in your stomach digest certain types of food that naturally we can't digest(every food based on cellulose for instance) or would be easier if they do it for us. Bacteria compete for the food in your stomach and if everything is ok there would be no food for the pathogenic bacteria so bad bacteria could not be able to survive in your stomach.
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It can be. There are enteropathogenic (ie. enteroinvasive and enterotoxigenic) strains of E. coli which cause a range of GI tract symptoms from very mild to very severe. At the more severe end of the spectrum, enteropathogenic E. coli causes bloody diarrhea (hemorrhagic colitis) and is usually protracted and accompanied by fever. Some strains cause hemolytic uremic syndrome (HUS) which is often lethal in infants.<P>cyber_indian said:
Just as a sidenote, some of the common bacterial mechanisms to survive acidic environments includes e.g. specialised cell wall configurations or H+/Cl- antiporters. Some acidophiles also intriguingly "flip" their membran potential and thus probably slow proton movemnt into the cell.
There is no such thing as bacteria. There's only aliens, and cats, and cat aliens with casts.
Starring...
Starring...
yes bacteria can live in the stomach,heliobactor pylori is the leading cause of ulcers in the world,they live IN stomach acid.
and giardi can survive and live inside your intenstines.
i have/had both,i know this for a fact.
if you want to worry about something,look up Toxoplasma Gondii,or search for parasite rex.
and giardi can survive and live inside your intenstines.
i have/had both,i know this for a fact.
if you want to worry about something,look up Toxoplasma Gondii,or search for parasite rex.