What Causes Recurring Urine Infection Along With Elevation In Creatinine Levels?

My father is 65 yr old and diabities patient.Beforethree months he was having urine infection,and there we find his cretinine is 6.Then he was given one dialysis but it does not work.After that he was on medicines and now his cretnine is 2.69.But still in every 15 days he got urine infection and then he used to give antibiotics.We are still not geting his problem of urine infection again and again.What to do now.