Poo is mostly E. coli true or false

[Harmonious_Discord]

A book I read claimed that human poo is mostly E. coli bodies. Is it?

[Hirka_T_Bawa]

I don’t have a cite handy, but this is incorrect… There are many other bacteria besides E. Coli that live in the intestines. However, a large part of human feces does contain bacteria, however I don’t know what percentage in weight it is.

One gram of human feces contains approx 10^13 microorganisms, but that is everything that lives in the intestine, not just E. Coli.

[Uncertain]

Hirka T.Bawa has it right. My recollection is that about 1/3 of the dry weight of feces is bacteria (mostly dead?). But E. coli is a minor constituent of the intestinal flora. It is the predominant aerobic component, so if you culture in the simplest way you’ll see a lot of it.

[Harmonious_Discord]

I think the author was trying to include all bacteria even though he stated E. coli, but 1/3 of the weight isn’t mostly to me.

[HorseloverFat]

From a random web page:
Water makes up about 3/5 of the weight of feces. Without the water feces are composed of about 1/3 undigested parts of food like fiber, 1/3 dead bacteria, and 1/3 unwanted mineral salts, mucus, bile contents, and little rubbed-off bits of intestinal lining.

[Never_Say_Dice]

So the big question is why don’t the dead bacteria get digested?

[friedo]

The bacteria is what digests stuff for you. All they ask for is the occasional load of delicious chyme, which they eat, then they poop out glorious nutrients for your small and large intestines to absorb, then they die.

So before we poop, the bacteria poop. Anaerobic digestion: It’s just a great circle of poop.

[DSeid]

These are bacteria that are living in the large intestine mostly. There it is mostly water resorbtion, not digestion, and in the large intestine it is the gut flora that does most of the digesting that gets done. As to gut flora that live elsewhere - they are adapted to survive there and have all sorts of neat tricks.

FWIW, Wikipedia claims that

Bacteria make up most of the flora in the colon[6] and 60% of the dry mass of feces.[2] Somewhere between 300[2] and 1000 different species live in the gut,[3] with most estimates at about 500.[4][5][7] However, it is probable that 99% of the bacteria come from about 30 or 40 species. … Most bacteria come from the genera Bacteroides, Clostridium, Fusobacterium,[2][8][9] Eubacterium, Ruminococcus, Peptococcus, Peptostreptococcus, and Bifidobacterium.[2][8] Other genera such as Escherichia and Lactobacillus are present to a lesser extent.[2] Species from the genus Bacteroides alone constitute about 30% of all bacteria in the gut, suggesting that that genus is especially important in the functioning of the host.[3]

[johnpost]

@Never_Say_Dice

So the big question is why don’t the dead bacteria get digested?

they likely do though not in the time frame of body transit. there are many niches in nature.

if any organic matter didn’t get eaten by something we would be up to our necks in it.

[DSeid]

More on gut flora!

The focus on aerobic microorganisms in the early decades of the last century led many scientists and medical personnel well into the 1970s (1980s?) to regard the intestinal bacterium named after Escherich (31), Escherichia coli, to be the predominating inhabitant of the human large bowel (personal experience). E. coli is a facultative organism able to grow on common laboratory media in atmospheres either free of or containing oxygen. The view that its populations dominated in the large bowel prevailed even though findings published as early as 1933 had revealed that anaerobic bacteria of the genus Bacteroides outnumbered E. coli in human feces (30). … <snip>

The indigenous communities reside in the distal small and large intestine.

Transient bacteria can be cultured from feces and from gastric and intestinal content. These organisms derive from ingesta and habitats above the gastrointestinal tract.

The combined populations in the indigenous communities in the small and large bowel can be enormous, exceeding one hundred trillion bacterial cells (109).

This enormous bacterial mass forms about one-half of the fecal mass (121).

The communities establish in the neonate in a pattern that can be recognized to be an ecological succession.

Some species resident in intestinal habitats form communities in the intestinal mucous gel lining the intestinal epithelium.

All members of the gastrointestinal communities obey ecological laws governing biological organisms; all communities are regulated by numerous complex forces including some exerted by the host (e.g., gastric pH) and some they exert themselves (e.g., colonization resistance).

The combined bacterial population, the microbiota, can be viewed as an organ of the body that is indispensable for life under ordinary conditions. …

And that article’s source was a 1980 article:

When faeces from nine healthy subjects on a metabolically controlled British-type diet were studied, bacteria comprised 54.7 +/- 1.7% of the total solids, fibre 16.7 +/- 0.8% and soluble material 24.0 +/- 1.3%. Bacteria therefore represent a much larger proportion of the faecal mass than was previously thought.

No idea how many dead vs alive though!

[Hari_Seldon]

One thing to keep in mind is that most strains of E. coli are harmless (unless they get to the bladder, which they can cause bladder infection). The deadly strains seem to come from farms that practice intensive animal husbandry in which the animals spend all their time immobilized in their own shit. Why this practice caused these deadly strains to evolve is not clear to me.

On the other hand, finding E. coli in food or water is a danger sign since it implies fecal contamination, not that the E. coli are themselves dangerous.

[janeslogin]

I would have thought that Klebsiella might be almost if not more by weight or volume, but then it has been a long time since I studied this crap literally.

[Smeghead]

@Hari_Seldon

One thing to keep in mind is that most strains of E. coli are harmless (unless they get to the bladder, which they can cause bladder infection). The deadly strains seem to come from farms that practice intensive animal husbandry in which the animals spend all their time immobilized in their own shit. Why this practice caused these deadly strains to evolve is not clear to me.

I have never heard this suggestion during my education as a microbiologist. I’d be interested to see a study supporting that.