MP16-14 RECTAL CULTURE PRIOR TO PROSTATE BIOPSY IDENTIFIES MEN AT RISK FOR INFECTION: A MULTI-INSTITUTIONAL INTERNATIONAL COLLABORATIVE STUDY

INTRODUCTION AND OBJECTIVES: The use of rectal swab cultures to guide antimicrobial prophylaxis for transrectal ultrasound (TRUS)-guided prostate biopsy has been suggested as a way to reduce infectious complications from antibiotic-resistant microorganisms. We assessed the incidence of fluoroquinolone resistance in men undergoing prostate biopsy and evaluated the effect of culture-directed prophylaxis on the risk of infectious complications after prostate biopsy. METHODS: All men who received prostate biopsies 2/1/13 e 10/31/13 at our institution were included in an IRB approved retrospective cohort study. At the discretion of the attending physician, patients received either a pre-procedural rectal swab and culture to guide antimicrobial prophylaxis, or routine prophylaxis with a fluoroquinolone antibiotic. Basic patient demographic and clinical information were collected, as well as data on any infectious complications within 30 days of biopsy. Fisher’s exact test and Welch’s t-test were used for statistical analysis. Confounding variables were controlled for with a multivariate logistic regression model. RESULTS: 347 patients were included in the study. Of these, 205 patients received a pre-procedure rectal swab culture and 142 did not. Average patient age was 62.6 and 64.4 years, respectively (p1⁄40.04). There was no difference in mean PSA value (p1⁄40.30) or age-adjusted Charlson comorbidity score (p1⁄40.10) between the two groups. 13.1% of rectal cultures demonstrated fluoroquinoloneresistant microorganisms. Infectious complications occurred in 0.9% of the rectal swab group and 2.9% of the control group (p1⁄40.16), which included hospital admissions for bacteremia, pyelonephritis, sepsis, or septic shock. Rectal swab culture-directed antibiotics were associated with a decreased risk for post-biopsy infection (RR 0.17, 95% CI 0.02-1.53). A multivariate logistic regression model demonstrated a decreased risk of infection if a rectal swab culture was done (p1⁄40.11). CONCLUSIONS: The incidence of fluoroquinolone resistance is relatively high in our patient population. Overall, infection rates after prostate biopsy are low, with a non-significant reduction in incidence of post-biopsy infection for patients receiving rectal swab-directed antimicrobial prophylaxis. Though not statistically significant, these differences remain clinically significant, given the severity of observed infectious complications.