What Is The Treatment For Strep In The Buttocks?

my 2 year old daughter keeps getting strep on her bottom (strep-butt). the first 2 times, we took her to the doctor and she tested positive after getting a rectal culture. now it looks like it back. she's experiencing pain while holding in her bowel movements and has a nasty rash on her bottom. i'm getting worried that this is chronic or that something more serious is going on.