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


Aylin Colpan, University of Minnesota Twin Cities
Brian Johnston, University of Minnesota Twin Cities
Stephen Porter, Minneapolis Veterans Affairs Health Care System
Connie Clabots, Minneapolis Veterans Affairs Health Care System
Ruth Anway, Minneapolis Veterans Affairs Health Care System
Lao Thao, Stanford University
Michael A. Kuskowski, University of Minnesota Twin Cities
Veronika Tchesnokova, University of Washington, Seattle
Evgeni V. Sokurenko, University of Washington, Seattle
James R. Johnson, University of Minnesota Twin Cities
Bradley L. Allen, University of Miami Leonard M. Miller School of Medicine
Gio J. Baracco, UT Southwestern Medical Center
Roger Bedimo, University of Colorado School of Medicine
Mary Bessesen, Louis Stokes Cleveland VA Medical Center
Robert A. Bonomo, Boston University School of Medicine
Stephen M. Brecher, VA Medical Center
Sheldon T. Brown, Icahn School of Medicine at Mount Sinai
Laila Castellino, Wright State University Boonshoft School of Medicine
Arundhati S. Desai, VA Medical Center
Fletcher Fernau, ARUP Laboratories
Mark A. Fisher, Washington University in St. Louis
James Fleckenstein, VA NCHCS Sacramento
Carol S. Fleming, VA Medical Center
Narla J. Fries, The George Washington University
Virginia L. Kan, University of Michigan Medical School
Carol A. Kauffman, Iowa City VA Health Care System
Stacey Klutts, VA Western New York Healthcare System
Michael Ohl, VA Western New York Healthcare System
Thomas Russo, VA Medical Center
Andrea Swiatlo, University of Mississippi Medical Center
Edwin Swiatlo, University of Mississippi Medical Center

Document Type

Journal Article

Publication Date



Clinical Infectious Diseases








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


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. © 2013 Published by Oxford University Press on behalf of the Infectious Diseases Society of America 2013. This work is written by (a) US Government employee(s) and is in the public domain in the US.