6 Year Old Daughter Recurrent Uti (kidney Mostly)with Scarred Underfunctioning

6 year old daughter recurrent uti (kidney mostly)with scarred underfunctioning right kidney.
currently has uti again....6th since 31st October - has had 5 admissions and a variety of antibiotics by oral and IV. This has happened many times over the years but becoming more frequent and regular.
renal scans mag 3 next week
dmsa shows right underfunctioning at 30%
sometimes mixed growth in samples but very symptomatic ans sepsis therefore treated with combination
always fecal bacterium - but treated for constipation and recent transit scan indicates not constipated. Scared there is a fistula? frequent frothy and bubbly urine, sometimes with but also without protein and not always with leucocytes . todays sample - day 3 of amoxicillin has full count for leucocytes and nitrites as well as blood and specific density. protein also present . high temperature and nausea, no appetite. Grey /brown urine with floating /turbalant. very smelly

advise please Thanks