Objective: To determine whether antibiotic treatment of asymptomatic bacteriuria in kidney transplant recipients could be useful to prevent pyelonephritis in these patients.

Design: Randomized prospective study. Setting: University Hospital with an active kidney transplantation program. Patients: Adult kidney transplant recipients. Interventions: Kidney transplant recipients with asymptomatic bacteriuria will be randomly assigned to be treated with antibiotics or to be followed without antibiotic therapy.

Measurements: Urine cultures will be collected weekly during the first month after transplantation, every 2 weeks until three months after transplantation, every month until 6 months after transplantation and every 3 months until 12 months after transplantation. Urine culture will be as well collected if urinary symptoms appeared.

Primary end points: To determine in both groups: the incidence of pyelonephritis.

Secondary end points: To determine outcomes in both groups (renal function, hospitalization, rejection, graft loss, opportunistic infections and mortality) and infection by multiresistant microorganisms.

Inclusion Criteria:

• Patients who receive a transplant allograft during study period

Exclusion Criteria:

• No acceptation of study