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

Abstract

Objective: • 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: • 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). • During both periods antimicrobial prophylaxis consisted of ciprofloxacin, co-amoxiclav and metronidazole except after August 2008 when co-amoxiclav was discontinued. • Amikacin was added to the prophylaxis protocol in the period 2007 and 2008.

Results: • 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. • In both periods, most of the strains causing the infections were ciprofloxacin resistant (2006: 13 of 14; 2007 and 2008: seven of eight). • 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. • 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). • 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: • We conclude that adding amikacin to fluoroquinolone-based antimicrobial prophylaxis in areas with high fluoroquinolone resistance confers significant benefit in preventing infections after TGB.