Urinary tract infection with burning.

Burning sensation while urination.more at night, two' to three times at night .as per culture as the most sensitive drugs were nitrofurantoin and Fosfomycin.so was advised Gentamicin 80mg IV BD for 5days along with Econorm thrice a day,Cranbe twice a day,Evalon cream at night.after completion of course routine repeated.. showing mild infection.burning sensation at night continues with using the toilet two times in between.had constipation in between and so had Duphalac two doses of 10 and 15 ml..followed by severe diarrhoea.now how should I proceed.. recurrent UTI.. vaginal hysterectomy done about 8years ago.my mother had been suffering from recurrent UTI for the past twelve years or more.This time it's been almost 15 days now.Its EColi with more than a lakh count..now routine shows 4-5 pus cells/hpf,2-3 epi cells/hpf,S turbid appearance.routine repeated after 5 days course of treatment.cranbe started only yesterday.Kindly advise how to treat her and make her feel normal again.