[jrabone]

We provide them a home, and in return they protect and clean us. They don't want to destroy their home, they would die, too.

Sorry but that is absolute, unmitigated rubbish. I spent 2 weeks in intensive care, with a surgical scar from my sternum to my groin which de-hisced (burst open) because my own bacteria tried to kill me.

While they might be symbiotic in the right place (eg. the gut), they'll kill you pretty quickly if they get out.

[dbingham]

You are over generalizing while also making appeals to emotion based upon your (admittedly terrifying, painful and difficult) experience. I'm sorry you had to go through that and hope life gets better for you.

But applying that emotional appeal to this argument is not valid. Yes, some bacteria are symbiotic in certain environments but extraordinarily dangerous if they escape into other parts of the body. There are particular gut bacteria that are especially notable in that regard. But there are thousands of species of bacteria that live in all parts of our body. The vast majority of these are harmless or even helpful, period. If they find themselves in an environment that isn't the specific niche they evolved for, they die.

While I haven't seen the research on the particular species discussed in the article, it is entirely possible (I would say likely) that it is one of those. Rather than one of the species that can wreck havoc if it escapes its proper environment.

[jrabone]

For hopefully the last time, I'm not talking about the bacteria in the product. All human beings defecate. Many (most?) clean themselves afterwards with their hands. If you do not practise adequate hygiene with a surfactant-based cleanser, those faecal bacteria are still stuck to the skin afterwards and transfer to anything you touch, where they may be picked up by someone else who is not in a position to deal with them. This is not an appeal to emotion, it is a fact which I happen to have had personal experience of.

[dllthomas]

By stating that the gut is the "right place" for these particular bacteria, you are begging the question. It is unquestionably the case that there are bacteria in our gut flora that we definitely do not want anywhere but the gut. It does not follow that this applies to all bacteria.

Compare pathology of the bacterium under discussion (http://microbewiki.kenyon.edu/index.php/Nitrosomonas_eutroph...) with one that more clearly doesn't belong anywhere but the gut (http://microbewiki.kenyon.edu/index.php/Escherichia_coli).