Hello sir and mam.I have low grade intermittent fever from last 2 months which come for some days and normal for few days again fever happen for some days like this pattern.i have done peripheral blood smear test which is normal, urine test is normal, thyroid,chest xray, calcium test, blood culture,esr all are normal.ultrasound show cystitis and ecogenic debris found in bladder.Then i have done urine culture show e coli bacteria colony of 100000 per ml. Antibiotic resistance test show resistance to more than 12 antibiotics only sensitivity to norfloxacin and ertapenem .i have no uti related symptoms like burning urine etc but only low grade periodic pattern intermittent fever.please advice