title: Clinical and microbiological determinants of infection after transrectal prostate biopsy.
abstract: BACKGROUND
  Increasing numbers of infections following transrectal prostate biopsy (TPB) at our hospital led us to investigate clinical and bacterial risk factors to determine if the colonizing rectal Escherichia coli population is the source.
  
  
  METHODS
  We performed an observational cohort study of men undergoing TPB (1 January 2010-6 February 2014) at the San Diego Veterans Affairs Medical Center. The primary outcome was clinically significant post-TPB infection. Rectal swabs were collected immediately before the biopsy and cultured selectively for fluoroquinolone-resistant gram-negative bacilli. Fluoroquinolone-resistant clinical and rectal E. coli isolates were compared using phylotyping, pulsed-field gel electrophoresis (PFGE) analysis, sequence typing, and virulence gene profiling.
  
  
  RESULTS
  Rectal colonization with fluoroquinolone-resistant organisms (98% E. coli) was detected in 121 of 764 subjects (15.8%). Post-TPB infection was more common among fluoroquinolone-resistant-colonized subjects than noncolonized subjects (13/121 [10.7%] vs 8/649 [1.2%]; P < .001). Presence of fluoroquinolone-resistant colonizing E. coli was the most significant host characteristic associated with post-TPB infection (odds ratio, 4.5 [95% confidence interval, 1.2-18.2]; P = .03). Escherichia coli infection isolates (n = 18) did not differ from E. coli rectal culture isolates (n = 68) for any of 49 virulence genes or ST131 status (all P > .05). The rectal and clinical isolates of all 9 men with paired isolates had indistinguishable PFGE patterns and identical antimicrobial susceptibility profiles.
  
  
  CONCLUSIONS
  The rectal colonizing E. coli population is the source for most fluoroquinolone-resistant post-TPB infections, regardless of clonal background or virulence traits. Screening cultures can identify nearly all patients at risk for fluoroquinolone-resistant post-TPB infection.
authors.affiliation: Veterans Affairs Healthcare System San Diego, Department of Urology, University of California, San Diego School of Medicine, La Jolla.
authors.forename: Michael A
authors.initials: MA
authors.lastname: Liss
authors.affiliation: Veterans Affairs Healthcare System Minneapolis, Department of Medicine, University of Minnesota, Minneapolis.
authors.forename: James R
authors.initials: JR
authors.lastname: Johnson
authors.affiliation: Veterans Affairs Healthcare System Minneapolis.
authors.forename: Stephen B
authors.initials: SB
authors.lastname: Porter
authors.affiliation: Veterans Affairs Healthcare System Minneapolis, Department of Medicine, University of Minnesota, Minneapolis.
authors.forename: Brian
authors.initials: B
authors.lastname: Johnston
authors.affiliation: Veterans Affairs Healthcare System Minneapolis.
authors.forename: Connie
authors.initials: C
authors.lastname: Clabots
authors.affiliation: Department of Urology, University of California, San Diego School of Medicine, La Jolla.
authors.forename: Kyle
authors.initials: K
authors.lastname: Gillis
authors.affiliation: Department of Urology, University of California, San Diego School of Medicine, La Jolla.
authors.forename: Unwanaobong
authors.initials: U
authors.lastname: Nseyo
authors.affiliation: Department of Urology, University of California, San Diego School of Medicine, La Jolla.
authors.forename: Marc
authors.initials: M
authors.lastname: Holden
authors.affiliation: Veterans Affairs Healthcare System San Diego, Department of Urology, University of California, San Diego School of Medicine, La Jolla.
authors.forename: Kyoko
authors.initials: K
authors.lastname: Sakamoto
authors.affiliation: Veterans Affairs Healthcare System San Diego, Departments of Medicine and Pathology, University of California, San Diego School of Medicine, La Jolla.
authors.forename: Joshua
authors.initials: J
authors.lastname: Fierer
mesh_terms: D000368:Aged; D001706:Biopsy / Q000009:adverse effects*; D002140:California / Q000453:epidemiology; D015331:Cohort Studies; D024881:Drug Resistance, Bacterial; D004926:Escherichia coli / Q000145:classification* / Q000235:genetics* / Q000302:isolation & purification; D004927:Escherichia coli Infections / Q000453:epidemiology* / Q000382:microbiology*; D024841:Fluoroquinolones / Q000494:pharmacology; D005838:Genotype; D006787:Hospitals, Veterans; D006801:Humans; D008297:Male; D008875:Middle Aged; D017720:Molecular Epidemiology; D058889:Molecular Typing; D011472:Prostatitis / Q000453:epidemiology* / Q000382:microbiology; D012007:Rectum / Q000382:microbiology; D012307:Risk Factors
chemical_list: D024841:Fluoroquinolones
keywords: antibiotic resistance; biopsy; infection; prostate