i am a firm believer that if you build it, they will come. all that is necessary is the right environment.
that said, the value of most probiotics is practically nil. you might explore soil based organisms. the Webmaster even has a baby poop enema that he describes.
but i would look at diet. perhaps some fermented food like kraut or kimchi or kombucha. like a stagnant pool in summer, you must build the right environment inside and the mosquitos, i mean bacteria, will find you.