The investigators hypothesize that antibiotic therapy for asymptomatic bacteriuria in renal transplant patients does not have impact on the development of symptomatic urinary tract infection (UTI) or progression of renal impairment in patients during the first year after transplantation.

Inclusion Criteria:

• Patients who are ≥1 month and ≤ 12 months after renal transplantation.
• Positive urine culture defined as ≥ 105 colony forming units (CFU) per milliliter of a known single pathogen.

Exclusion Criteria:

• Any one of the following signs and symptoms: fever, abdominal pain, dysuria, frequency, urgency, flank pain, costovertebral-angel tenderness or tenderness over the transplanted kidney
• Active infections in another site
• Leucocytosis (WBC >18.000K/micl) or leucopenia (WBC < 3.000 K/micl)
• Elevation of serum creatinine of more than 15% of its baseline level
• Obstructive or other urological complications following transplantation as known foreign device (stent/double-J-Cath, any catheter) in the urinary tract system, known obstruction of the transplanted kidney, indwelling or intermittent catheterization
• Pregnant or lactating women.
• Candidates to invasive urologic procedures.
• Inability to return for regular follow up.
• Previous enrollment in this study.
• Patients who incapable of giving informed consent.