TY - JOUR T1 - Evolutionary history of the global emergence of the <em>Escherichia coli</em> epidemic clone ST131 JF - bioRxiv DO - 10.1101/030668 SP - 030668 AU - Nicole Stoesser AU - Anna E. Sheppard AU - Louise Pankhurst AU - Nicola de Maio AU - Catrin E. Moore AU - Robert Sebra AU - Paul Turner AU - Luke W. Anson AU - Andrew Kasarskis AU - Elizabeth M. Batty AU - Veronica Kos AU - Daniel J. Wilson AU - Rattanaphone Phetsouvanh AU - David Wyllie AU - Evgeni Sokurenko AU - Amee R. Manges AU - Timothy J. Johnson AU - Lance B. Price AU - Timothy E. A. Peto AU - James R. Johnson AU - Xavier Didelot AU - A. Sarah Walker AU - Derrick W. Crook AU - Modernising Medical Microbiology Informatics Group (MMMIG) Y1 - 2015/01/01 UR - http://biorxiv.org/content/early/2015/11/06/030668.abstract N2 - Background Escherichia coli sequence type 131 (ST131) has emerged globally as the most predominant lineage within this clinically important species, and its association with fluoroquinolone and extended-spectrum cephalosporin resistance impacts significantly on treatment. The evolutionary histories of this lineage, and of important antimicrobial resistance elements within it, remain unclearly defined.Results This study of the largest worldwide collection (n = 215) of sequenced ST131 E. coli isolates to date demonstrates that clonal expansion of two previously recognized antimicrobial-resistant clades, C1/H30R and C2/H30Rx, started around 25 years ago, consistent with the widespread introduction of fluoroquinolones and extended-spectrum cephalosporins in clinical medicine. These two clades appear to have emerged in the United States, with the expansion of the C2/H30Rx clade driven by the acquisition of a blaCTX-M-15-containing IncFII-like plasmid that has subsequently undergone extensive rearrangement. Several other evolutionary processes influencing the trajectory of this drug-resistant lineage are described, including sporadic acquisitions of CTX-M resistance plasmids, and chromosomal integration of blaCTX-M within sub-clusters followed by vertical evolution. These processes are also occurring for another family of CTX-M gene variants more recently observed amongst ST131, the blaCTX-M-14/14-like group.Conclusions The complexity of the evolutionary history of ST131 has important implications for antimicrobial resistance surveillance, epidemiological analysis, and control of emerging clinical lineages of E. coli. These data also highlight the global imperative to reduce specific antibiotic selection pressures, and demonstrate the important and varied roles played by plasmids and other mobile genetic elements in the perpetuation of antimicrobial resistance within lineages. ER -