title: Clinical and molecular correlates of virulence in Escherichia coli causing bloodstream infection following transrectal ultrasound-guided (TRUS) prostate biopsy.
abstract: OBJECTIVE
  Prevention and management of Escherichia coli bacteraemia following transrectal ultrasound-guided (TRUS) prostate biopsy has become increasingly complicated by antimicrobial resistance, particularly to fluoroquinolones. Moreover, the globally disseminated, multiresistant sequence type 131 (ST131) E. coli clonal group has recently been described as a major pathogen in the setting of post-biopsy sepsis. Accordingly, we sought to further explore the clinical and molecular epidemiology of post-TRUS biopsy E. coli bacteraemia by comparing the phylogenetic, resistance and virulence characteristics of post-TRUS biopsy E. coli bloodstream isolates with E. coli bloodstream isolates from male patients with spontaneous urosepsis.
  
  
  METHODS
  Multiplex PCR was used to compare the phylogenetic group and virulence-associated genes between post-biopsy E. coli isolates and E. coli bloodstream isolates from males with spontaneous urosepsis. Antimicrobial resistance profiles were also compared between the two groups. In addition, we compared the clinical characteristics and outcomes of post-TRUS biopsy patients with E. coli ST131 versus non-ST131 bacteraemia.
  
  
  RESULTS
  Although post-TRUS biopsy E. coli isolates were more extensively antimicrobial resistant than isolates from males with spontaneous urosepsis, they harboured significantly fewer virulence-associated genes. In addition, ST131 isolates were significantly less virulent in nature than other isolates from phylogenetic group B2. Clinical outcomes did not differ between patients with post-biopsy ST131 versus non-ST131 bacteraemia.
  
  
  CONCLUSIONS
  Our data provide new insights into the molecular pathogenesis of post-TRUS biopsy E. coli bacteraemia, and suggest that antimicrobial resistance, rather than virulence genotype, is the most important bacterial trait associated with an increased risk of infection following TRUS biopsy.
authors.affiliation: Faculty of Medical and Health Sciences, University of Auckland, Auckland, New Zealand.
authors.forename: Deborah A
authors.initials: DA
authors.lastname: Williamson
authors.forename: Joshua T
authors.initials: JT
authors.lastname: Freeman
authors.forename: Stephen
authors.initials: S
authors.lastname: Porter
authors.forename: Sally
authors.initials: S
authors.lastname: Roberts
authors.forename: Siouxsie
authors.initials: S
authors.lastname: Wiles
authors.forename: David L
authors.initials: DL
authors.lastname: Paterson
authors.forename: James R
authors.initials: JR
authors.lastname: Johnson
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D016470:Bacteremia / Q000453:epidemiology / Q000382:microbiology* / Q000473:pathology*; D001706:Biopsy / Q000009:adverse effects*; D004269:DNA, Bacterial / Q000235:genetics; D024881:Drug Resistance, Bacterial; D004926:Escherichia coli / Q000145:classification / Q000235:genetics / Q000302:isolation & purification* / Q000472:pathogenicity; D004927:Escherichia coli Infections / Q000453:epidemiology / Q000382:microbiology* / Q000473:pathology*; D005838:Genotype; D006801:Humans; D008297:Male; D008826:Microbial Sensitivity Tests; D008875:Middle Aged; D017720:Molecular Epidemiology; D060885:Multiplex Polymerase Chain Reaction; D010802:Phylogeny; D011467:Prostate / Q000601:surgery*; D016896:Treatment Outcome; D014774:Virulence; D037521:Virulence Factors / Q000235:genetics; D055815:Young Adult
chemical_list: D004269:DNA, Bacterial; D037521:Virulence Factors
keywords: antimicrobial resistance; fluoroquinolones; sequence type 131