Transperineal Prostate Biopsy is Associated With Lower Tissue Core Pathogen Burden Relative to Transrectal Biopsy: Mechanistic Underpinnings for Lower Infection Risk in the Transperineal Approach.

OBJECTIVE

To understand the mechanistic basis for reduced infectious complications in transperineal (TP) prostate biopsy, we sought to determine whether TP prostate biopsy is associated with a lower degree of pathogen introduction into the prostate relative to transrectal (TR) biopsy.

MATERIALS AND METHODS

In men scheduled for prostate biopsy for standard clinical indications, rectal and perineal skin swabs, and 2 extra biopsy cores, were obtained. Specimens underwent DNA extraction followed by next-generation sequencing and standard laboratory culture. Microbial quantity and composition were determined and compared between prostate core biopsy tissue from individuals who underwent TP vs TR biopsy.

RESULTS

Twenty-three men were accrued to the study. Biopsy core tissue from the TP group had less microbial diversity (15.0 vs 25.8 phylogenetic clades/sample, P = .0004) and had a lower quantity of known pathogens (36.3 vs 104.2 normalized counts of pathogens/sample, P = .018) relative to the TR group. TP group tissue core flora was more attributable to the perineal than rectal source (P = .047). Viable Escherichia coli was isolated from 45% of the TR group cores, but none in the TP group (P = .014).

CONCLUSION

Biopsy tissue from individuals who undergo TP biopsy harbors a lower human pathogenic bacterial load than those who undergo TR biopsy, with a minimal risk of viable E. coli. Our results elucidate a possible mechanism for reduced infectious risk associated with TP biopsy relative to TR biopsy and a rational basis for widespread implementation of TP biopsy.