E. coli ST131 antibiotic resistance genes.

1+/− indicates presence/absence of indicated gene; Numbers in parentheses refer to order of genes in plasmid; horizontal lines indicate boundaries for antibiotic resistance gene cassettes that are commonly separated by Insertion Sequence (IS) elements.2Like in pEK499, the blaTEM-1 gene in pEC958 is found as part of a complex transposon, separated from the other antibiotic resistance genes by the replication region. In pEC958, however, there is an additional ∼24 kb region encoding conjugation genes between blaTEM-1 and the replication region.3All three plasmids carry a catB4 gene truncated by an IS26 element at nucleotide position 442 (relative to pEK499 catB4). In addition, pC15-1a catB has been further disrupted by the inversion of the aacA4/oxa-1 cassette.4An ampC gene with 100% amino acid identity to CMY-23 (gb|ABD94117) was identified within a putative genomic island within the EC958 chromosome.