we tend to get re-exposed to various types of strep throughout our lives. what you are experiencing now as an adult would have nothing to do with your negative test as an infant. yes strep b as well as several other bacterial (strep is not a virus) types can grow out of a urine culture when you have an urinary tract infection but this was not lingering on since birth. strep throat is due to group a strep -- a different "bug" entirely.
is it possible that a newborn that tested negative for group b strep to start showing symptoms of it as a young adult? . my mother tested positive after she had me but i had tested negative for it. as a child i was frequently getting strep throat. i had it so many times i had my tonsils removed and haven't had any strep throat since. now as a young adult i get urinary tract infections frequently and with my last one my doctor told me there was strep in my urine cultures and they told me that i'm a carrier of the strep virus. so is it possible that i could now be showing symptoms of group b strep?