Polymerase chain reaction amplification of bacterial 16s rRNA genes in prostate biopsies from men without chronic prostatitis

Objectives. A previously reported study using nested polymerase chain react ion (PCR) analysis indicated the presence of DNA from a variety of prokaryo tic microorganisms in 77% of transperineal prostate biopsies from patients with chronic nonbacterial prostatitis. Because that study did not include a control group, we investigated whether microbial DNA could also be found i n transperineal prostate biopsies obtained from men who did not have a hist ory of prostatitis. Methods. Transperineal biopsies of both lobes of the prostate were obtained under ultrasound guidance from 9 patients with localized adenocarcinoma of the prostate. DNA was extracted from the prostatic tissue and two-round am plification performed using nested primers from a highly conserved region o f the bacterial 16s rRNA gene. Amplified DNA was purified and sequenced, an d sequences obtained were compared to bacterial rRNA genes recorded in GenB ank. Results. Eleven of 18 biopsy specimens from 8 of 9 patients were positive f or bacterial DNA by PCR. Sequence data indicated a predominant organism in 8 of 11 specimens, with greater than 95% homology to DNA from several diffe rent genera of bacteria, including Escherichia and Bacteroides. All 9 contr ol samples from the instruments before biopsy were negative. Conclusions. The presence of bacterial 16s rRNA genes in prostatic tissue i s not specific for chronic prostatitis and occurred in most of our patients with localized prostate cancer. Whether the presence of such bacteria is r elated to the development of prostatic diseases such as prostatitis or pros tatic cancer will require carefully controlled trials, including appropriat e control groups examined identically. (C) 1999, Elsevier Science Inc. All rights reserved.