Figure A1. Pulsed-field gel electrophoresis profile dendrogram of 87 diverse isolates of Escherichia coli ST131. Isolates for the dendrogram, which represent a 15% subsample of the total population (n = 579), were selected randomly after deliberate inclusion of 2 representatives of each pulsotype with >6 members (indicated by brackets) plus the earliest previously reported isolate (from 1985) and the earliest present isolate (from 1967). YEAR, year of isolation or submission to reference laboratory; FQ-R, fluoroquinolone-resistant; ESBL, extended-spectrum β-lactamase; CTX-M-15, presence of blaCTX-M-15 (as detected by PCR); POS, positive (i.e., trait present); 2008–2009, interval during which isolate was collected. Scale is percent profile similarity.