Why hasn't Kal-el's e. coli killed us all?

I mean, besides the fact that Superman is fictional and all.

Follow me here: Kal rockets to Earth with a full load of Kryptonian intestinal flora, which would enter the Earth’s biosphere with his excreta. Why haven’t they killed all of us by now? Super-powered bacteria are nothing to mess with!

Great. Something new to worry about.

That’s what the white kryptonite is for.

Remember that Superman’s intestinal flora are living, well, where the sun don’t shine.

But Supe is still super even at night, or in a subway, or in an enclosed office, or…

Unlike that horrible pansy in Part 4 that Supes ended up… throwing… into… the sun.

Superman’s super-metabolism uses 100% of all materials he ingests. He does not excrete, therefore the Kryptococci do not escape into the environment.

Well, newborns don’t have any intestinal flora; it takes a few days of exposure to the environment and taking in fluid for those to develop. So, depending on how soon after his birth his parents sent him to us, his GI tract might have been sterile.

E. coli is an Earth bacteria. They don’t have it on Krypton.

yes, but only because he has been exposed to the yellow sun, and it wears off slowly. The coli in his intestinal tract have never been exposed.

… at least until they’re excreted…

Just because they’re super doesn’t mean they’re pathogenic. His bacteria are equally devoted to Truth, Justice, the American Way, and the Lack of Horrible Intestinal Squirty Diseases.

Kryptonian powers are only found in higher-order vertebrates, not bacteria. If you need a fanwank.

Krypton’s e. coli need the super nutrition from super feces to florish. Our ordinary feces are unable to sustain them.

But, depending on how Silver Agey we’re being, Kryptonian powers are inherent in everything Kryptonian – including inanimate objects.

Anyway, this sort of stuff is why Kryptonians come equipped with x-ray vision. Kal just has to give the ol’ stink-eye to his stinky pie, irradiate the whole mess, and the world is safe for humanity once more.

There’s a lot of space between vertebrates and bacteria. How about a Super Tapeworm?

I didn’t realize any form of kryptonite came in a roll like that. Learn something new every day.

On a related note, how does Supergirl’s hair stay styled? Does she have some kind of super-hairspray?

Chuck Norris round kick’s her hair.

Superman’s intestinal flora cannot flourish on Earth. Their own superpowers prevent them from doing so.

Consider: under a yellow sun, Superman himself does not need to eat. Therefore, there is every reason to assume that his intestinal bacteria do not need to ingest nutrients either. And just as Superman does not suffer from constant hunger pangs, his superpowered *K. coli * likewise do not experience any impetus to metabolize; all their energy needs are already satisfied. Since they never actually absorb any nutrients, they never increase in size and never reproduce.

More than that, Terrifel, intestinal flora are usually looking for specific proteins to eat and it’s rather iffy that they would turn up on Earth. If he had any they probably died out harmlessly and been replaced by Earth bacteria a long time ago.

Though I do wonder what happens when you expose Kryptonian bacteria to red kryptonite.