Fluoroquinolone resistant rectal colonization predicts risk of infectious complications after transrectal prostate biopsy

Purpose: Infection after transrectal prostate biopsy has become an increasing concern due to fluoroquinolone resistant bacteria. We determined whether colonization identified by rectal culture can identify men at high risk for post-transrectal prostate biopsy infection.

Materials and methods: Six institutions provided retrospective data through a standardized, web based data entry form on patients undergoing transrectal prostate biopsy who had rectal culture performed. The primary outcome was any post-transrectal prostate biopsy infection and the secondary outcome was hospital admission 30 days after transrectal prostate biopsy. We used chi-square and logistic regression statistical analysis.

Results: A total of 2,673 men underwent rectal culture before transrectal prostate biopsy from January 1, 2007 to September 12, 2013. The prevalence of fluoroquinolone resistance was 20.5% (549 of 2,673). Fluoroquinolone resistant positive rectal cultures were associated with post-biopsy infection (6.6% vs 1.6%, p <0.001) and hospitalization (4.4% vs 0.9%, p <0.001). Fluoroquinolone resistant positive rectal culture increased the risk of infection (OR 3.98, 95% CI 2.37-6.71, p <0.001) and subsequent hospital admission (OR 4.77, 95% CI 2.50-9.10, p <0.001). If men only received fluoroquinolone prophylaxis, the infection and hospitalization proportion increased to 8.2% (28 of 343) and 6.1% (21 of 343), with OR 4.77 (95% CI 2.50-9.10, p <0.001) and 5.67 (95% CI 3.00-10.90, p <0.001), respectively. The most common fluoroquinolone resistant bacteria isolates were Escherichia coli (83.7%). Limitations include the retrospective study design, nonstandardized culture and interpretation of resistance methods.

Conclusions: Colonization of fluoroquinolone resistant organisms in the rectum identifies men at high risk for infection and subsequent hospitalization from prostate biopsy, especially in those with fluoroquinolone prophylaxis only.