Escherichia coli sequence type 131 (ST131) subclone h30 as an emergent multidrug-resistant pathogen among US Veterans

Aylin Colpan, Brian Johnston, Stephen Porter, Connie Clabots, Ruth Anway, Lao Thao, Michael A. Kuskowski, Veronika Tchesnokova, Evgeni V. Sokurenko, James R. Johnson, Bradley L. Allen, Gio J. Baracco, Roger Bedimo, Mary Bessesen, Robert A. Bonomo, Stephen M. Brecher, Sheldon T. Brown, Laila Castellino, Arundhati S. Desai, Fletcher FernauMark A. Fisher, James Fleckenstein, Carol S. Fleming, Narla J. Fries, Virginia L. Kan, Carol A. Kauffman, Stacey Klutts, Michael Ohl, Thomas Russo, Andrea Swiatlo, Edwin Swiatlo

Research output: Contribution to journalArticlepeer-review

152 Scopus citations


Background. Escherichia coli sequence type 131 (ST131), typically fluoroquinolone-resistant (FQ-R) and/or extended-spectrum -lactamase (ESBL)-producing, has emerged globally. We assessed its prevalence and characteristics among US veterans.Methods. In 2011, 595 de-identified E. coli clinical isolates were collected systematically within 3 resistance groups (FQ-susceptible [FQ-S], FQ-R, and ESBL-producing) from 24 nationally distributed Veterans Affairs Medical Centers (VAMCs). ST131 and its H30 subclone were detected by polymerase chain reaction and compared with other E. coli for molecular traits, source, and resistance profiles.Results. ST131 accounted for 78% (184/236) of FQ-R and 64.2% (79/123) of ESBL-producing isolates, but only 7.2% (17/236) of FQ-S isolates (P <. 001). The H30 subclone accounted for ≥95% of FQ-R and ESBL-producing, but only 12.5% of FQ-S, ST131 isolates (P <. 001). By back-calculation, 28% of VAMC E. coli isolates nationally represented ST131. Overall, ST131 varied minimally in prevalence by specimen type, inpatient/outpatient source, or locale; was the most prevalent ST, followed distantly by ST95 and ST12 (13% each); and accounted for ≥40% (-lactams), >50% (trimethoprim-sulfamethoxazole, multidrug), or >70% (ciprofloxacin, gentamicin) of total antimicrobial resistance. FQ-R and ESBL-producing ST131 isolates had higher virulence scores than corresponding non-ST131 isolates. ST131 pulsotypes overlapped extensively among VAMCs.Conclusions. Among US veterans, ST131, primarily its H30 subclone, accounts for most antimicrobial-resistant E. coli and is the dominant E. coli strain overall. Possible contributors include multidrug resistance, extensive virulence gene content, and ongoing transmission. Focused attention to ST131, especially its H30 subclone, could reduce infection-related morbidity, mortality, and costs among veterans.

Original languageEnglish (US)
Pages (from-to)1256-1265
Number of pages10
JournalClinical Infectious Diseases
Issue number9
StatePublished - Nov 1 2013


  • Escherichia coli infections
  • ST131
  • antimicrobial resistance
  • extended-spectrum beta-lactamases
  • veterans

ASJC Scopus subject areas

  • Microbiology (medical)
  • Infectious Diseases


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