Occurrence of ESBL-Producing <i>Escherichia coli</i> ST131, Including the <i>H30</i> -Rx and C1-M27 Subclones, Among Urban Seagulls from the United Kingdom

Abstract

Antimicrobial resistance is a public health concern. Understanding any role that urban seagulls may have as a reservoir of resistant bacteria could be important for reducing transmission. This study investigated fecal <i>Escherichia coli</i> isolates from seagulls (herring gulls and lesser black-backed gulls) to determine the prevalence of extended-spectrum cephalosporin-resistant (ESC-R) and fluoroquinolone-resistant <i>E. coli</i> among gull species from two cities (Taunton and Birmingham) in the United Kingdom (UK). We characterized the genetic background and carriage of plasmid-mediated resistance genes in extended-spectrum β-lactamase (ESBL)-producing <i>E. coli</i> obtained from these birds. Sixty ESC-R <i>E. coli</i> isolates were obtained from 39 seagulls (39/78, 50%), of which 28 (28/60, 46.7%) were positive for plasmid-mediated CTX-M and/or AmpC β-lactamase resistance genes. Among these, <i>bla</i>_CTX-M-15, <i>bla</i>_CTX-M-14, and <i>bla</i>_CMY-2 predominated. Three isolates belonging to the B2-ST131 clone were detected, of which two harbored <i>bla</i>_CTX-M-15 (typed to C2/H30Rx) and one harbored <i>bla</i>_CTX-M-27 and was typed to C1/H30-R (recently described as the C1-M27 sublineage). The plasmid-mediated quinolone resistance (PMQR) gene carriage prevalence (11.7%) consisted of <i>aac(6')-Ib-cr</i> and <i>qnrB</i> genes. No carbapenem or colistin resistance genes were detected. Urban seagulls in the UK are colonized and can spread major antimicrobial-resistant <i>E. coli</i> isolates harboring ESBL and PMQR determinants, including clinically important strains such as the pandemic clone B2-ST131 and the C1-M27 subclade. This is the first report of ST131-C1-M27 subclade in wildlife in the UK and in seagulls worldwide.