title: Escherichia coliSequence Type 131H30 Is the Main Driver of Emerging Extended-Spectrum-β-Lactamase-ProducingE.coliat a Tertiary Care Center.
abstract: TheH30 strain ofEscherichia colisequence type 131 (ST131-H30) is a recently emerged, globally disseminated lineage associated with fluoroquinolone resistance and, via itsH30Rx subclone, the CTX-M-15 extended-spectrum beta-lactamase (ESBL). Here, we studied the clonal background and resistance characteristics of 109 consecutive recentE. coliclinical isolates (2015) and 41 historical ESBL-producingE. coliblood isolates (2004 to 2011) from a public tertiary care center in California with a rising prevalence of ESBL-producingE. coliisolates. Among the 2015 isolates, ST131, which was represented mainly by ST131-H30, was the most common clonal lineage (23% overall). ST131-H30 accounted for 47% (8/17) of ESBL-producing, 47% (14/30) of fluoroquinolone-resistant, and 33% (11/33) of multidrug-resistant isolates. ST131-H30 also accounted for 53% (8/14) of dually fluoroquinolone-resistant, ESBL-producing isolates, with the remaining 47% comprised of diverse clonal groups that contributed a single isolate each. ST131-H30Rx, with CTX-M-15, was the major ESBL producer (6/8) among ST131-H30 isolates. ST131-H30 andH30Rx also dominated (46% and 37%, respectively) among the historical ESBL-producing isolates (2004 to 2011), without significant temporal shifts in relative prevalence. Thus, this medical center's recently emerging ESBL-producingE. colistrains, although multiclonal, are dominated by ST131-H30 andH30Rx, which are the only clonally expanded fluoroquinolone-resistant, ESBL-producing lineages. Measures to rapidly and effectively detect, treat, and control these highly successful lineages are needed.IMPORTANCEThe ever-rising prevalence of resistance to first-line antibiotics among clinicalEscherichia coliisolates leads to worse clinical outcomes and higher health care costs, thereby creating a need to discover its basis so that effective interventions can be developed. We found that theH30 subset withinE. colisequence type 131 (ST131-H30) is currently, and has been since at least 2004, the mainE. colilineage contributing to key resistance phenotypes-including extended-spectrum-beta-lactamase (ESBL) production, fluoroquinolone resistance, multidrug resistance, and dual ESBL production-plus-fluoroquinolone resistance-at a United States tertiary care center with a rising prevalence of ESBL-producingE. coliisolates. This identifies ST131-H30 as a target for diagnostic tests and preventive measures designed to curb the emergence of multidrug-resistantE. coliisolates and/or to blunt its clinical impact.
authors.affiliation: VA Medical Center, Minneapolis, Minnesota, USA; University of Minnesota, Minneapolis, Minnesota, USA.
authors.forename: James R
authors.initials: JR
authors.lastname: Johnson
authors.affiliation: VA Medical Center, Minneapolis, Minnesota, USA; University of Minnesota, Minneapolis, Minnesota, USA.
authors.forename: Brian
authors.initials: B
authors.lastname: Johnston
authors.affiliation: VA Medical Center, Minneapolis, Minnesota, USA; University of Minnesota, Minneapolis, Minnesota, USA.
authors.forename: Paul
authors.initials: P
authors.lastname: Thuras
authors.affiliation: Los Angeles BioMedical Research Center at Harbor-Harbor-UCLA Medical Center, Torrance, California, USA.
authors.forename: Bryn
authors.initials: B
authors.lastname: Launer
authors.affiliation: University of Washington, Seattle, Washington, USA.
authors.forename: Evgeni V
authors.initials: EV
authors.lastname: Sokurenko
authors.affiliation: Los Angeles BioMedical Research Center at Harbor-Harbor-UCLA Medical Center, Torrance, California, USA; University of California, Los Angeles, California, USA.
authors.forename: Loren G
authors.initials: LG
authors.lastname: Miller
keywords: Escherichia coli infections; ST131; ST131-H30; antimicrobial resistance; clonality; extended-spectrum β-lactamase; fluoroquinolone resistance; molecular epidemiology; phylogenetic analysis