The purpose of this clinical trial is compare the incidence of symptomatic or asymptomatic bacteriuria after transrectal ultrasound guided prostate biopsy using a single dose of fosfomycin 3 g one hour before the biopsy compared to observed with the use of a single dose of ciprofloxacin 500 mg 1 hour before biopsy.

Transrectal ultrasound guided (TRUS) prostate biopsy is the procedure of choice for the diagnosis of prostate cancer. This technique is usually safe and well tolerated with a low incidence of serious complications. However, one of these complications, the bacterial infection can be complicated and cause urinary sepsis. The investigators have developed different regimens of antibiotic prophylaxis. Most of them include administering oral fluoroquinolones. In this area, approximately 40% of the strains of E. coli are resistant to ciprofloxacin (fluoroquinolone). Therefore, research is warranted alternative prophylactic approaches. Fosfomycin is an antibiotic ancient underused in recent decades that in recent years has been proposed as an alternative treatment for infections caused by multidrug-resistant microorganisms.

Inclusion Criteria:

• Age > 18 years
• Patients with prostate-specific antigen (PSA) values >4 ng/ml or presenting either abnormality in rectal examination
• Patients who accept to participate in the study signing the consent informed form

Exclusion Criteria:

• Allergy to anyone of the study drug
• Intolerance to anyone of the study drug
• Urinary infection with positive uroculture
• Clinical finds suggesting infections
• Antimicrobial treatment during the las 4 weeks
• Patients with vesicle catheter
• Patients in dialysis
• Patients in hemodialysis