Group A comprised 205 patients that received a single dose of levofloxacin 500 mg orally, with an average age of 66.22 years (±7.95) and PSA mean of 23.07 ng/mL; 43.9% have DM, 4.3% presented febrile urinary tract infection with a positive culture for E. coli and Klebsiella pneumoniae and two patients had sepsis (0.97%), with average prostate volume of 65.80 cc, and 90.17% in this group had overweight. The gene discussed is KLK3; the disease is urinary tract infection.