Please don't do this here.

It’s not unusual in the slightest for people living together to have very similar microbiomes even in the absence of direct contact like that.

I always pose the question - your gut was sterile when you were born, so how do you think the bacteria got their in the first place? The answer is oral-fecal transmission.

You get fecal bacteria on your hands, you touch an object, someone else touches it and they put their hands in their mouth.

You must be one of the guys I team up with sometimes on playstation. (tbh it's a fair question in this context)