title: Abrupt emergence of a single dominant multidrug-resistant strain of Escherichia coli.
abstract: BACKGROUND
  Fluoroquinolone-resistant Escherichia coli are increasingly prevalent. Their clonal origins--potentially critical for control efforts--remain undefined.
  
  
  METHODS
  Antimicrobial resistance profiles and fine clonal structure were determined for 236 diverse-source historical (1967-2009) E. coli isolates representing sequence type ST131 and 853 recent (2010-2011) consecutive E. coli isolates from 5 clinical laboratories in Seattle, Washington, and Minneapolis, Minnesota. Clonal structure was resolved based on fimH sequence (fimbrial adhesin gene: H subclone assignments), multilocus sequence typing, gyrA and parC sequence (fluoroquinolone resistance-determining loci), and pulsed-field gel electrophoresis.
  
  
  RESULTS
  Of the recent fluoroquinolone-resistant clinical isolates, 52% represented a single ST131 subclonal lineage, H30, which expanded abruptly after 2000. This subclone had a unique and conserved gyrA/parC allele combination, supporting its tight clonality. Unlike other ST131 subclones, H30 was significantly associated with fluoroquinolone resistance and was the most prevalent subclone among current E. coli clinical isolates, overall (10.4%) and within every resistance category (11%-52%).
  
  
  CONCLUSIONS
  Most current fluoroquinolone-resistant E. coli clinical isolates, and the largest share of multidrug-resistant isolates, represent a highly clonal subgroup that likely originated from a single rapidly expanded and disseminated ST131 strain. Focused attention to this strain will be required to control the fluoroquinolone and multidrug-resistant E. coli epidemic.
authors.affiliation: Veterans Affairs Medical Center and University of Minnesota, Minneapolis, USA. johns007@umn.edu
authors.forename: James R
authors.initials: JR
authors.lastname: Johnson
authors.forename: Veronika
authors.initials: V
authors.lastname: Tchesnokova
authors.forename: Brian
authors.initials: B
authors.lastname: Johnston
authors.forename: Connie
authors.initials: C
authors.lastname: Clabots
authors.forename: Pacita L
authors.initials: PL
authors.lastname: Roberts
authors.forename: Mariya
authors.initials: M
authors.lastname: Billig
authors.forename: Kim
authors.initials: K
authors.lastname: Riddell
authors.forename: Peggy
authors.initials: P
authors.lastname: Rogers
authors.forename: Xuan
authors.initials: X
authors.lastname: Qin
authors.forename: Susan
authors.initials: S
authors.lastname: Butler-Wu
authors.forename: Lance B
authors.initials: LB
authors.lastname: Price
authors.forename: Maliha
authors.initials: M
authors.lastname: Aziz
authors.forename: Marie-Hélène
authors.initials: MH
authors.lastname: Nicolas-Chanoine
authors.forename: Chitrita
authors.initials: C
authors.lastname: Debroy
authors.forename: Ari
authors.initials: A
authors.lastname: Robicsek
authors.forename: Glen
authors.initials: G
authors.lastname: Hansen
authors.forename: Carl
authors.initials: C
authors.lastname: Urban
authors.forename: Joanne
authors.initials: J
authors.lastname: Platell
authors.forename: Darren J
authors.initials: DJ
authors.lastname: Trott
authors.forename: George
authors.initials: G
authors.lastname: Zhanel
authors.forename: Scott J
authors.initials: SJ
authors.lastname: Weissman
authors.forename: Brad T
authors.initials: BT
authors.lastname: Cookson
authors.forename: Ferric C
authors.initials: FC
authors.lastname: Fang
authors.forename: Ajit P
authors.initials: AP
authors.lastname: Limaye
authors.forename: Delia
authors.initials: D
authors.lastname: Scholes
authors.forename: Sujay
authors.initials: S
authors.lastname: Chattopadhyay
authors.forename: David C
authors.initials: DC
authors.lastname: Hooper
authors.forename: Evgeni V
authors.initials: EV
authors.lastname: Sokurenko
mesh_terms: D018830:Adhesins, Escherichia coli / Q000235:genetics; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D060965:Clonal Evolution; D027081:DNA Gyrase / Q000235:genetics; D027101:DNA Topoisomerase IV / Q000235:genetics; D004269:DNA, Bacterial / Q000235:genetics; D024901:Drug Resistance, Multiple, Bacterial / Q000235:genetics*; D004926:Escherichia coli / Q000187:drug effects* / Q000235:genetics*; D004927:Escherichia coli Infections / Q000188:drug therapy / Q000453:epidemiology / Q000382:microbiology*; D036781:Fimbriae Proteins / Q000235:genetics; D024841:Fluoroquinolones / Q000494:pharmacology*; D006801:Humans; D017720:Molecular Epidemiology; D058885:Multilocus Sequence Typing
chemical_list: D018830:Adhesins, Escherichia coli; D000900:Anti-Bacterial Agents; D004269:DNA, Bacterial; D024841:Fluoroquinolones; C058769:fimH protein, E coli; D036781:Fimbriae Proteins; D027101:DNA Topoisomerase IV; D027081:DNA Gyrase