Tehran University of Medical Sciences Acta Medica Iranica 0044-6025 52 9 2014 09 15 664 670 EN Zhoobin Heidari Bateni Department of Urology, Hasheminejad Hospital, Iran University of Medical Sciences, Tehran, Iran. Hossein Shahrokh Department of Urology, Hasheminejad Hospital, Iran University of Medical Sciences, Tehran, Iran. Hormoz Salimi Department of Urology, Hasheminejad Hospital, Iran University of Medical Sciences, Tehran, Iran. Hossein Safari Department of Urology, Hasheminejad Hospital, Iran University of Medical Sciences, Tehran, Iran. Meghdad Tabatabai Department of Urology, Hasheminejad Hospital, Iran University of Medical Sciences, Tehran, Iran. Dariush Saedi Department of Radiology, Hasheminejad Hospital, Iran University of Medical Sciences, Tehran, Iran. 2015 10 11 To investigate and compare the infectious and non-infectious complications of single-dose versus multiple-dose antibiotic therapy for trans-rectal ultrasound (TRUS)-guided biopsy of the prostate. Patients were enrolled in a prospective randomized study that was designed to investigate the effects of single-dose versus multiple-dose antimicrobial prophylaxis regimen mainly on asymptomatic bacteriuria, urinary tract infection (UTI) without fever, fever and urinary septicemia. The single-dose group received one ciprofloxacin 500 mg tablet and two metronidazole 250 mg tablets at 2 hours before the biopsy, while the multiple-doses group received those every 12 hours from 3 days before the biopsy. One-hundred and sixty patients were evaluated in two groups and bacteriuria in urinalysis was encountered in 12 patients (15%) in the single-dose group and four patients (5%) in the multiple-dose group, with a significant difference (P=0.035). UTI without fever occurred in six patients (7.5%) in the single-dose group and one patient (1.25%) in the multiple-dose group, with no significant difference (borderline P=0.053). After biopsy, three patients (3.75%) returned with fever due to UTI and bacteremia in the single-dose group and none in the multiple-dose group, but with no significant difference (P=0.08). Regarding non-infectious complications, there were no significant differences between the two groups. Using prophylactic antibiotics for prostate biopsy in multiple doses, and at least 3 days before the procedure significantly reduces the rate of bacteriuria compared with a single-dose regimen. https://acta.tums.ac.ir/index.php/acta/article/view/4666 https://acta.tums.ac.ir/index.php/acta/article/download/4666/4625