Fluoroquinolone resistance in the rectal carriage of men in an active surveillance cohort: Longitudinal analysis

Purpose Rectal swabs can identify men with fluoroquinolone resistant bacteria and decrease the infection rate after transrectal ultrasound guided prostate biopsy by targeted antimicrobial prophylaxis. We evaluated the rate of fluoroquinolone resistance in an active surveillance cohort with attention to factors associated with resistance and changes in resistance with time. Materials and Methods We evaluated 416 men with prostate cancer on active surveillance who underwent rectal swabs to assess the rate of fluoroquinolone resistance compared to that in men undergoing diagnostic transrectal ultrasound guided prostate biopsy. The chi-square test and Student t-test were used to compare categorical and continuous variables, respectively. Poisson regression analysis was used for multivariate analysis. Results On the initial swab fluoroquinolone resistance was found in 95 of 416 men (22.8%) on active surveillance compared to 54 of 221 (24.4%) in the diagnostic biopsy cohort (p = 0.675). Diabetes was found in 4.0% of the fluoroquinolone sensitive group vs 14.7% of the resistant group (p <0.001). Biopsy history was not associated with resistance. Of those with a resistant first swab 62.9% had a resistant second swab and 88.9% of those with 2 resistant swabs showed resistance on the third swab. Of men with a sensitive first swab 10.6% showed resistance on the second swab and 10.6% of those with 2 sensitive swabs had resistant third swabs. Conclusions One of 4 men who present for surveillance and diagnostic transrectal ultrasound guided prostate biopsy have rectal flora resistant to fluoroquinolone. Resistance is significantly associated with diabetes but the number of prior biopsies is not. Men with fluoroquinolone resistant flora tend to remain resistant with time.