Predictors of fluoroquinolone-resistant bacterial colonization prior to prostate biopsy: a secondary analysis of two...

The prevalence of fluoroquinolone resistant (FQR) rectal bacterial colonization ranges from 15-20%, and FQR colonization increases the risk of prostate biopsy infectious complications. FQR bacteria have been identified in 50% of prostate biopsy infectious complications. However, predictors of FQR remain unclear, so we aimed to elucidate these characteristics.

A secondary analysis of two multicenter clinical trials (NCT04815876 and NCT04843566) comprising 11 sites was conducted on men who underwent rectal swab cultures prior to prostate biopsy. Rectal swab cultures were examined to identify FQR bacteria and factors associated with post-biopsy infections. Sites with fewer than 30 rectal swab results were aggregated. Multivariable logistic regression was used to identify whether age, race, ethnicity, diabetes, smoking history, or site were associated with FQR colonization.

FQR bacterial colonization was identified in 145 (16%, 95% CI: 13%, 18%) of 925 patients. One site within the same metropolitan area as the reference site had increased odds of FQR colonization [OR 3.68 (CI: 1.98, 6.83, p < 0.001)]. Transrectal biopsy infection risk increased with FQR rectal bacteria (3.9% vs. 0.8%; risk difference 3.2%; 95% CI: -1.3%, 7.5%; p = 0.017). There was an insignificantly increased odds of FQR colonization for Asian men (OR 1.94, 95% CI: 0.92, 3.89; p = 0.070).

FQR rectal colonization was associated with higher rates of post-TR biopsy infection despite targeted prophylaxis. FQR colonization rates differed significantly across trial sites. Future research should continue to identify FQR predictors and their underlying causal pathways to reduce the risk of infectious complications.