How much fecal bacteria does it take to get you sick? I may have ingested traces of it : (

Probably no worries. If the source of contact healthy, almost certainly you won't get sick. For infected feces, the amount to transmit can be microscopic (e.g. norovirus, Shigella) but more for others (e.g. Salmonella). Every day we all contact small amounts of fecal bacteria (e.g. shaking hands with someone who didn't wash after toilet, pets, sinks, etc). Mostly it's harmless, and to some extent actually healthy.