Escherichia coli O25b-ST131: a pandemic, multiresistant, community-associated

Escherichia coli sequence type 131 (ST131) is a worldwide pandemic clone, causing predominantly community-onset antimicrobial-resistant infection. Its pandemic spread was identified in 2008 by utilizing multilocus sequence typing (MLST) of CTX-M-15 extended-spectrum b-lactamase-producing E. coli from three continents. Subsequent research has confirmed the worldwide prevalence of ST131 harbouring a broad range of virulence and resistance genes on a transferable plasmid. A high prevalence of the clone (30%–60%) has been ident-ified amongst fluoroquinolone-resistant E. coli. In addition, it potentially harbours a variety of b-lactamase genes; most often, these include CTX-M family b-lactamases, and, less frequently, TEM, SHV and CMY b-lactamases. Our knowledge of ST131’s geographical distribution is incomplete. A broad distribution has been demonstrated amongst antimicrobial-resistant E. coli from human infection in Europe (particularly th