Transrectal prostate biopsy (TRPB) is a well established procedure used to obtain tissue for the histological diagnosis of carcinoma of the prostate. Despite the fact that TRPB is generally considered a safe procedure, it may be accompanied by traumatic and infective complications, including asymptomatic bacteriuria (bacteria in the urine), urinary tract infection (UTI), transitory bacteremia (bacteria in the blood), fever episodes, and sepsis (pathogenic microorganisms or their toxins in the blood). Although infective complications after TRPB are well known, there is uncertainty about the necessity and effectiveness of routine prophylactic antibiotics and their adverse effects, as well as a clear lack of standardization.

To evaluate the effectiveness and adverse effects of prophylactic antibiotic treatment in TRPB.

The search covered the principal electronic databases: MEDLINE, EMBASE, LILACS and the Cochrane Central Register of Controlled Trials (CENTRAL). Experts were consulted and references from the relevant articles were scanned.

All randomized, controlled trials (RCTs) of men who underwent TRPB and received prophylactic antibiotics or placebo/no treatment, were selected, and all RCTs looking at one type of antibiotic versus another, including comparable dosages, routes of administration, frequency of administration, and duration of antibiotic treatment.

Two reviewers (ELZ, OACC) independently selected included trials and extracted study data. Any disagreements were resolved by a third party (NRNJ).

Overall, more than 3500 references were considered and 19 original reports with a total of 3599 patients were included.There were 9 trials analysing antibiotics versus placebo/no treatment, with all outcomes significantly favouring antibiotic use (P < 0.05) (I(2) = 0%), including bacteriuria (risk ratio (RR) 0.25 (95% confidence interval (CI) 0.15 to 0.42), bacteremia (RR 0.67, 95% CI 0.49 to 0.92), fever (RR 0.39, 95% CI 0.23 to 0.64), urinary tract infection (RR 0.37, 95% CI 0.22 to 0.62), and hospitalization (RR 0.13, 95% CI 0.03 to 0.55). Several classes of antibiotics were effective prophylactically for TRPB, while the quinolones, with the highest number of studies (5) and patients (1188), were the best analysed. For 'antibiotics versus enema', we analysed four studies with a limited number of patients. The differences between groups for all outcomes were not significant. For 'antibiotic versus antibiotic + enema', only the risk of bacteremia (RR 0.25, 95% CI 0.08 to 0.75) was diminished in the 'antibiotic + enema group'. Seven trials reported the effects of short-course (1 day) versus long-course (3 days) antibiotics. Long course was significantly better than short-course treatment only for bacteriuria (RR 2.09, 95% CI 1.17 to 3.73). For 'single versus multiple dose', there was significantly greater risk of bacteriuria for single-dose treatment (RR 1.98, 95% CI 1.18 to 3.33). Comparing oral versus systemic administration - intramuscular injection (IM), or intravenous (IV) - of antibiotics, there were no significant differences in the groups for bacteriuria, fever, UTI and hospitalization.

Antibiotic prophylaxis is effective in preventing infectious complications following TRPB. There is no definitive data to confirm that antibiotics for long-course (3 days) are superior to short-course treatments (1 day), or that multiple-dose treatment is superior to single-dose.