Novel Conjugative Plasmid from Escherichia coli of Swine Origin That Coharbors the Multiresistance Gene cfr and the 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 these two 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 colocation of the multiresistance cfr gene with an extended-spectrum-β-lactamase gene on a conjugative plasmid may support the dissemination of these genes by coselection.