My Daughter Age 15 Gets Alot Of Bladder Or Uti

my daughter age 15 gets alot of bladder or uti s and she gets them sometims one after the other like days apart. she is in the guardianship of 2 nasty wackos so when she visits i give her the tools to deal with them at home but i heard that reacurances of uti and bladder infections can be a sign of kidney problems. she was a premee and i was told to keep an eye on her major organs...should i worry and what can i do?