Not likely. Your gut microbe actively defend their "territory" in the gut. They are not going to give up such valuable real estate without a fight. This is called microbial antagonism. So you may ingest all sorts of bacteria be it sex or just eating, if you are healthy you already have microbes in place and whatever you are ingesting basically can't easily take hold because of this. Not saying it can't happen at all, it is just that the microbes are not just "passively" there, they are there and intend to stay. That involves various biological processes they use to make sure they do. One is to simply take up all the real estate so something coming through has no space to colonize.