My 9 months baby boy having frequent UTI(3 times) and found Bacteria in urine c/s at 4th month we admitted and found that mild hydronephrosis for left
kidney,after 2 months we did again ultrasound and MCUG both are normal.again urine infection occured and after using antibiotics again it is coming to normal.bacteria present in urine belongs to stool bacteria.but in stool examination and culture no bacteria was found.please clarify why frequent UTI happening to my baby.