Adding amikacin to fluoroquinolone-based antimicrobial prophylaxis reduces prostate biopsy infection rates

Level of Evidence 4 What's known on the subject? and What does the study add? Fluoroquinolones are almost universally used as antimicrobial prophylaxis for prevention of infections after transrectal ultrasound guided prostate biopsy. However, many recent studies have identified an alarming trend of increasing fluoroquinolone resistance leading to a rise in infections after biopsy. This indicates the unsuitability of ciprofloxacin as appropriate antibiotic prophylaxis. In this study, we have demonstrated a significant reduction in post biopsy infections by adding amikacin to fluoroquinolone based prophylaxis. OBJECTIVE center dot To examine the efficacy of adding amikacin to fluoroquinolone-based antimicrobial prophylaxis in preventing transrectal ultrasonography-guided prostate biopsy (TGB) associated infections. PATIENTS AND METHODS center dot Infections after TGB were compared before adding amikacin to antimicrobial prophylaxis (2006) with those that occurred after adding amikacin to the prophylaxis (2007 and 2008). center dot During both periods antimicrobial prophylaxis consisted of ciprofloxacin, co-amoxiclav and metronidazole except after August 2008 when co-amoxiclav was discontinued. center dot Amikacin was added to the prophylaxis protocol in the period 2007 and 2008. RESULTS center dot Before adding amikacin 11 of 281 (3.9%) patients developed infections after TGB (seven urinary tract infections (UTIs) and seven bacteraemias) whereas after adding amikacin six UTIs and two bacteraemias occurred in 590 (1.4%) patients. center dot In both periods, most of the strains causing the infections were ciprofloxacin resistant (2006: 13 of 14; 2007 and 2008: seven of eight). center dot Overall, there is strong statistical evidence that the total infection rate was significantly reduced after the inclusion of amikacin into the prostate biopsy prophylaxis regimen. center dot In 2007 and 2008 when amikacin was included in prophylaxis, the bacteraemia rate was reduced to just over one-tenth of the rate in 2006 before introducing amikacin (P = 0.002). center dot Although just failing to reach the conventional significance level of 0.05, the evidence suggests a reduction in UTI by an estimated 60% after adding amikacin. CONCLUSION center dot We conclude that adding amikacin to fluoroquinolone-based antimicrobial prophylaxis in areas with high fluoroquinolone resistance confers significant benefit in preventing infections after TGB.