Novel conjugative plasmid from Escherichia coli of swine origin that co-harbors the multi-resistance gene cfr and the 3 extended-spectrum β-lactamase gene bla_CTX-M-14b

Two porcine Escherichia coli isolates harbored the cfr gene on conjugative plasmids of 38,405 bp (pGXEC6) and 41,646 bp (pGXEC3). In both plasmids, the cfr gene was located within a 4,612-bp region containing a tnpA-IS26-cfr-IS26-Δhyp element. Plasmid pGXEC3 was almost identical to pGXEC6, except for a 3,235-bp ISEcp1-blaCTX-M-14b insertion. The co-location of the multi-resistance gene cfr with an extended-spectrum β-lactamase gene on a conjugative plasmid may support the dissemination of both genes by co-selection.