Dissemination of pCT-like IncK plasmids harboring CTX-M-14 extended-spectrum ß-lactamase among clinical Escherichia coli isolates in the United Kingdom.

IncK plasmids encoding CTX-M-14 extended-spectrum ß-lactamase (ESBL) and highly related to plasmid pCT were detected in 13 of 67 (19%) human clinical isolates of Escherichia coli with a group 9 CTX-M-type ESBL from the United Kingdom and in 2 quality assurance isolates. None of these E. coli strains was related to the cattle strain from which pCT was originally characterized.