Our hypothesis is that 30 days of oral levofloxacin (FDA approved antibiotic) in patients with persistent viremia (BK virus found in blood) will impair progress to BK virus induced kidney damage by significantly decreasing or eliminating BK virus in the blood.

Inclusion Criteria:

• Living and cadaveric kidney transplant recipients over the age of 18 years with BK viremia

Exclusion Criteria:

• Female patients of childbearing age who are pregnant or in whom adequate contraception cannot be maintained.
• Patients with active infections, history of malignancy/Posttransplant Lymphoproliferative Disease (PTLD) serologic positivity to HIV.
• Patients with evidence of urinary tract obstruction causing allograft dysfunction, unless corrected by time of enrollment.
• Patients with clinical or morphological evidence of recurrence of primary disease.
• Patients with a history of allergic reaction to quinolone antibiotics.
• Patients with history of prolong QT interval
• Patients with recurrent hypoglycemic episodes
• Patients with history of myasthenia gravis
• Patients taking Thioridazine