[Source: Clinical Infectious Diseases, full page: (LINK). Abstract, edited.]


Escherichia coli Sequence Type 131 (ST131) as an Emergent Multidrug-resistant Pathogen among U.S. Veterans


Aylin Colpan a, Brian Johnston a,b, Stephen Porter b, Connie Clabots b, Ruth Anway b, Lao Thao c, Michael A. Kuskowski a,b, Veronika Tchesnokova d, Evgeni V. Sokurenko d, James R. Johnson a,b, for the VICTORY (Veterans Influence of Clonal Types on Resistance: Year 2011) Investigators*

Author Affiliations: <SUP>a</SUP>University of Minnesota, Minneapolis, MN <SUP>b</SUP>Minneapolis Veterans Affairs Health Care System, Minneapolis, MN <SUP>c</SUP>Stanford University, Palo Alto, CA <SUP>d</SUP>University of Washington, Seattle, WA

Corresponding author: James R. Johnson, MD, Infectious Diseases (111F), VA Medical Center, 1 Veterans Drive, Minneapolis, MN 55417. johns007@umn.edu

Alternate corresponding author: Aylin Colpan, MD, Infectious Diseases (111F), VA Medical Center, 1 Veterans Drive, Minneapolis, MN 55417.

* The VICTORY Investigators include: Bradley L. Allen, M.D., Ph.D. (Roudebush VAMC and Indiana University School of Medicine, Indianapolis, IN), Gio J. Baracco, MD (Miami VA Healthcare System [HCS] and University of Miami Miller School of Medicine, Miami, FL), Roger Bedimo, MD, MS, FACP (VA North Texas HCS and UT Southwestern Medical Center, Dallas, TX), Mary Bessesen, MD (Department of Veterans Affairs Eastern Colorado HCS and University of Colorado-Denver School of Medicine, Denver, CO), Robert Bonomo, MD (Cleveland VAMC, Cleveland, OH), Stephen M. Brecher, Ph.D. (VA Boston HCS and BU School of Medicine, Boston, MA), Sheldon T. Brown, MD (James J. Peters VAMC, Bronx, NY, and Mt. Sinai School of Medicine, NY, NY), Laila Castellino, MD (VAMC and Wright State University Boonshoft School of Medicine, Dayton OH), Arundhati S. Desai, MD (Kansas City VAMC, Kansas City, MO), Fletcher Fernau, BA (James J. Peters VAMC, Bronx, NY), Mark A. Fisher, Ph.D. (University of Utah Department of Pathology, and ARUP Laboratories, Salt Lake City, UT), James Fleckenstein, MD (Washington University, St. Louis, MO), Carol S. Fleming, BA, MT(ASCP), CLS (VA NCHCS Sacramento, Mather, CA), Narla J Fries, CLS, MT(ASCP) (James A. Haley VAMC, Tampa, FL), Virginia Kan, MD, FACP (VA Medical Center and George Washington University, Washington, DC), Carol A. Kauffman, MD (VA Ann Arbor HCS and University of Michigan Medical School, Ann Arbor, MI), Stacey Klutts, PhD (Iowa City VAMC and University of Iowa, Iowa City, IA), Michael Ohl, MD, MSPH (Iowa City VAMC and University of Iowa, Iowa City, IA), Thomas Russo, MD (Buffalo VAMC and SUNY at Buffalo, Buffalo, NY), Andrea Swiatlo MS, MT(ASCP) (VAMC, Jackson, MS), and Edwin Swiatlo, MD, PhD (VAMC and University of Mississippi Medical Center, Jackson, MS).


Abstract

Background.

Escherichia coli sequence type 131 (ST131), typically fluoroquinolone-resistant (FQ-R) and/or extended-spectrum beta-lactamase (ESBL)-producing, has emerged globally. We assessed its prevalence and characteristics among U.S. veterans.


Methods.

In 2011, 595 de-identified E. coli clinical isolates were collected systematically within three resistance groups (FQ-susceptible [FQ-S], FQ-R, and ESBL-producing) from 24 nationally distributed Veterans Affairs Medical Centers (VAMCs). ST131 and its H30 sub-clone were detected by PCR 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 sub-clone 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% (beta-lactams),>50% (TMP-SMZ, 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 amongst VAMCs.


Conclusions.

Among U.S. veterans ST131, primarily its H30 sub-clone, 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 sub-clone, could reduce infection-related morbidity, mortality, and costs among veterans.


Received April 9, 2013. Accepted May 20, 2013.

Published by Oxford University Press on behalf of the Infectious Diseases Society of America 2013.


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