Reoccuring UTI in eleven year old daughter.

Patient: My 11 year old daughter keeps having reoccuring urine infections. She is now on her 5th set of antibiotics. The only symptom she has is the smell of the urine, which is very foul but no stinging or urgency to go. It seems to clear whilst taking the medication but within two days of finishing the course the smell is back. I am becoming more concerned there is an underlying issue? She is also going through puberty at the moment and I was wondering if this could have any relationship. She is v.clean hygenically. Please could you give me some advice as I dont know how else to help her.