Human poop can have many different strains of E coli in it, but most healthy people can ingest a tiny amount like you did without becoming seriously ill. If you feel that you need to vomit, then vomit, because that will expel most of the bacteria, if you do it quickly enough. If you get diarrhea, then don't try to suppress it unless it goes on for several days, because that also expels many bacteria. If you stay sick for more than a couple of days, go to the doctor, who can prescribe antibiotics.
