Ask A Scientist General Science Archive

name Dianna
status other
grade other
location HI

Question - what are the normal flora in the
stomach AND intestines? helicobacter pylori is normally in the
stomach, what other entities, including yeast or anything else?
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Dianna,
There is a spectacularly huge number of microbiota
(natural flora) in the GI system. The stomach itself
is host to very few--the acidic conditions (pH around
2) prevent the flora from calling the stomach home.
However, some lactobacillus and yeast may live there
in addition to the H. pylori you mentioned.

The large and small intestines, however,are a
different matter. The large intestine, in addition to
candida(yeast), plays host to around 300 types of
microbiota, including Klebsiella, enterococcus, E.
coli, proteus, bifidobacterium, bacteroids, and many
may more.

The small intestine hosts a smaller subset of these
bacteria, as well as candida.

For more primary sources of information on
microbiota.....go to your local University or college
with a Biomedical Library, and look up the American
Journal of Clinical Nutrition Volume 23, from 1970.
In that journal are several papers on intestinal
flora.

--Michelle Weinberger
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When I was in school and when I began teaching all of the textbooks stated 
that the stomach was a sterile cavity due to the acidity of the stomach 
contents. Then Helicobacter pylori was found to exist there. As far as I 
know, it is the only organism capable of living in acid of that low of a pH. 
But who knows? New things are discovered every day. As far as the intestines 
go, it depends on where in the intestines you look. The part nearest the 
stomach, the duodenum, is also considered sterile. The jejunum, the middle 
part, is sterile at the stomach end but gets less basic toward the large 
intestine end, so some bacteria can exist toward the end of that section. 
The ileum, or the last third, is closest to the large intestine and has 
increasing amounts of organisms.

vanhoeck
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