Editorial commentary: fluoroquinolone-resistant intestinal organisms and infections after prostate biopsy: shifting sands of the prevention narrative.

Transrectal ultrasound–guided prostate biopsies continue to be the gold-standard procedure for the diagnosis of prostate cancer. Prostate biopsies are being performed in growing numbers. This is due to rising longevity, an increase in screening programs, and larger numbers of men in active surveillance protocols and men requiring rebiopsy. An increasing incidence of severe infective illness after transrectal prostate biopsies in this decade has led to a rising tide of interest in infections after biopsies. Although overall morbidity has remained mostly contained, the management of these infections imposes a considerable financial and resource burden on healthcare systems [1]. There has been an increasing awareness that the rate of ciprofloxacin-resistant infections after biopsy correlates with the carriage of fluoroquinolone-resistant bacteria in the intestinal microbiota of men undergoing biopsy. This knowledge has been based on the observed similarity between bacteria present in the intestinal flora and those cultured from clinical isolates of men who go on to develop infections. This single-center observational study by Liss et al [2], published in this issue of Clinical Infectious Diseases, has built on what has hitherto been assumed, and has demonstrated that there were no differences between pulsed-field gel electrophoresis (PFGE) patterns or antimicrobial susceptibility profiles in Escherichia coli infection isolates and E. coli rectal isolates in 9 men with paired isolates, strongly suggesting that rectal E. coli is the source of infections. Interestingly, the authors have also noted that non–sequence type (ST) 131 clones were as likely to cause infection as ST131 clones, implying that the underlying virulence of ST131 may be exaggerated in the context of infections after prostate biopsy. In their patients, the increased proclivity for fluoroquinolone-resistant bacteria to cause infections could not be explained by any differences in detection of the ST131 clone, which is purportedly more virulent, or by virulence characteristics between the infecting and colonizing strains. Therefore, it is conceivable that direct inoculation of the bacteria into the prostate lessens the need for special virulence characteristics to initiate infection. The study was a retrospective review of data on 1638 biopsies. However, due to the inherent weaknesses of retrospective studies, incomplete data capture, and nonavailability of rectal cultures done beforehand, the cohort was whittled down to less than half that number (764 patients). Furthermore, selecting only 78 patients for PFGE analysis led to a similarity analysis being conducted in only 9 men, and thus the finding of similar E. coli PGFE profiles between clinical isolates and rectal isolates lacks the statistical robustness that one would have liked to see. Thus, a larger study exploring this similarity would be a welcome addition to literature on the topic. Liss et al also found that hospital admissions in the preceding year were predictive of infections, but there is currently no mechanism to explain this observation. Equally intriguing has been the observation that 65 men who had rectal cultures 1–2 weeks before biopsy had a significantly lower prevalence of resistant E. coli colonization than men who had a culture done on the day of biopsy. In the absence of any intervention during the interval Received 5 December 2014; accepted 6 December 2014; electronically published 16 December 2014. Correspondence: Deepak Batura, MBBS, MS, MCh, FRCS, Department of Urology, London North West Healthcare NHS Trust, Ealing Hospital, Southall, London UB1 3HW, UK (deepakbatura@gmail.com). Clinical Infectious Diseases 2015;60(7):988–9 © The Author 2014. Published by Oxford University Press on behalf of the Infectious Diseases Society of America. All rights reserved. For Permissions, please e-mail: journals. permissions@oup.com. DOI: 10.1093/cid/ciu1133