Fluoroquinolone-resistant Escherichia coli carriage in transrectal prostate biopsy patients without infectious complications

Fluoroquinolones are a commonly used prophylaxis in transrectal ultrasound-guided prostate biopsy (TRUS-Bx), even though fluoroquinolone-resistant Escherichia coli has been associated with infectious complications after TRUS-Bx. The present study describes fluoroquinolone resistance mechanisms and antimicrobial susceptibility among intestinal E. coli , isolated from TRUS-Bx patients in a prospective study showing very few infectious prostate biopsy adverse events. This Multi-IMPROD sub-study included a total of 336 patients who received either ciprofloxacin, levofloxacin, or fosfomycin as prophylaxis before TRUS-Bx. E. coli could be cultured from 278 fecal swab samples, and 27 (9.7%) of these showed resistance to ciprofloxacin, and 14 (5.0%) were susceptible with increased exposure (I). Chromosomal and transferable fluoroquinolone resistance mechanisms were found among ciprofloxacin non-susceptible isolates, but both qnr genes and single gyrA mutations were found also among the ciprofloxacin-susceptible E. coli population. Low-level fluoroquinolone resistance is commonly associated with ESBL production in Enterobacterales . However, ESBL and qnr genes were not associated in our material, 14 isolates were ESBL producers and only 14.3% of them had the qnr gene, although 85.7% of the ESBL producers were ciprofloxacin non-susceptible. In the Multi-IMPROD substudy, only two mild urinary tract infections were reported, indicating that the antimicrobial susceptibility or resistance pattern of E. coli does not correlate with the onset of post-biopsy adverse events. We conclude that in our clinical settings, ciprofloxacin and levofloxacin prophylaxis is effective, and no severe post-biopsy infections were detected despite the intestinal colonization of genotypically and phenotypically fluoroquinolone-resistant E. coli . ### Competing Interest Statement The authors have declared no competing interest. ### Funding Statement This study was funded by the Sigrid Juselius Foundation (for Peter J. Bostrom), and Finnish Governmental Special Funding, The Cancer Foundation Finland, University of Turku Combined Research Funding, and the Turku University Hospital Foundation (for Juha Knaapila). ### Author Declarations I confirm all relevant ethical guidelines have been followed, and any necessary IRB and/or ethics committee approvals have been obtained. Yes The details of the IRB/oversight body that provided approval or exemption for the research described are given below: Hospital District of Southwest Finland and Turku Clinical Research Centre gave ethical approval for this work, research approval number 72/1801/2014 I confirm that all necessary patient/participant consent has been obtained and the appropriate institutional forms have been archived, and that any patient/participant/sample identifiers included were not known to anyone (e.g., hospital staff, patients or participants themselves) outside the research group so cannot be used to identify individuals. Yes I understand that all clinical trials and any other prospective interventional studies must be registered with an ICMJE-approved registry, such as ClinicalTrials.gov. I confirm that any such study reported in the manuscript has been registered and the trial registration ID is provided (note: if posting a prospective study registered retrospectively, please provide a statement in the trial ID field explaining why the study was not registered in advance). Yes I have followed all appropriate research reporting guidelines and uploaded the relevant EQUATOR Network research reporting checklist(s) and other pertinent material as supplementary files, if applicable. Yes All data produced in the present study are available upon reasonable request to the authors