Escherichia coli Sequence Type 131 H 30 Is the Main Driver of Emerging Extended-Spectrum-β-Lactamase-Producing E. coli at a Tertiary Care Center

James R Johnson; Brian Johnston; Paul Thuras; Bryn Launer; Evgeni V Sokurenko; Loren G Miller

doi:10.1128/mSphere.00314-16

Escherichia coli Sequence Type 131 H 30 Is the Main Driver of Emerging Extended-Spectrum-β-Lactamase-Producing E. coli at a Tertiary Care Center

mSphere. 2016 Nov 23;1(6):e00314-16. doi: 10.1128/mSphere.00314-16. eCollection 2016 Nov-Dec.

Authors

James R Johnson¹, Brian Johnston¹, Paul Thuras¹, Bryn Launer², Evgeni V Sokurenko³, Loren G Miller⁴

Affiliations

¹ VA Medical Center, Minneapolis, Minnesota, USA; University of Minnesota, Minneapolis, Minnesota, USA.
² Los Angeles BioMedical Research Center at Harbor-Harbor-UCLA Medical Center, Torrance, California, USA.
³ University of Washington, Seattle, Washington, USA.
⁴ Los Angeles BioMedical Research Center at Harbor-Harbor-UCLA Medical Center, Torrance, California, USA; University of California, Los Angeles, California, USA.

Abstract

The H30 strain of Escherichia coli sequence type 131 (ST131-H30) is a recently emerged, globally disseminated lineage associated with fluoroquinolone resistance and, via its H30Rx subclone, the CTX-M-15 extended-spectrum beta-lactamase (ESBL). Here, we studied the clonal background and resistance characteristics of 109 consecutive recent E. coli clinical isolates (2015) and 41 historical ESBL-producing E. coli blood isolates (2004 to 2011) from a public tertiary care center in California with a rising prevalence of ESBL-producing E. coli isolates. 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 and H30Rx 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-producing E. coli strains, although multiclonal, are dominated by ST131-H30 and H30Rx, 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. IMPORTANCE The ever-rising prevalence of resistance to first-line antibiotics among clinical Escherichia coli isolates 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 the H30 subset within E. coli sequence type 131 (ST131-H30) is currently, and has been since at least 2004, the main E. coli lineage 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-producing E. coli isolates. This identifies ST131-H30 as a target for diagnostic tests and preventive measures designed to curb the emergence of multidrug-resistant E. coli isolates and/or to blunt its clinical impact.

Keywords: Escherichia coli infections; ST131; ST131-H30; antimicrobial resistance; clonality; extended-spectrum β-lactamase; fluoroquinolone resistance; molecular epidemiology; phylogenetic analysis.

Grants and funding

I01 CX000920/CX/CSRD VA/United States