Hello and thanks for your question. Please be patient as I respond: I may be in the OR or seeing a patient and will respond.
I would recommend seeing a urologist who specializes in voiding dysfunction. You should have a Ct scan of the kidneys to rule out a stone which can cause recurrent infections. You should have a look in your bladder to make sure your bladder or urethra doesn't have a pocket called a diverticulum which can be a cause. If they are both normal, I would recommend a test called video Urodynamics to evaluate your bladders ability to hold urine, not reflux back to your kidneys and empty properly. If all of these tests are normal, then placing you on a prophylactic regimen with something called hiprex or mandelamine ( along with lactobacillus or acidophilus) is a nice choice on a daily basis to help prevent the cycle of infections and allow the normal vaginal flora to reestablish and prevent this viscous cycle from reoccuring.

Then she should have a ct scan of her kidneys to ensure there are no stones or anatomical abnormalities. If the ct scan is normal, a Urodynamics would be a good next step. The purpose of all of this is to be sure there is no easily reversible cause for the infections. If all of this is normal, then placing her on a prophylactic regimen for 6 months should break the cycle of infections and allow the normal vaginal flora to return to help prevent the vicious cycle from recurring.