Tn6674 Is a Novel Enterococcal optrA-Carrying Multiresistance Transposon of the Tn554 Family

The novel 12,932-bp nonconjugative multiresistance transposon Tn6674 was identified in the chromosomal DNA of a porcine Enterococcus faecalis strain. Tn6674 belongs to the Tn554 family of transposons. It shares the same arrangement of the transposase genes tnpA, tnpB, and tnpC with Tn554. However, in addition to the Tn554-associated resistance genes spc and erm(A), Tn6674 harbored the resistance genes fexA and optrA. Circular forms of Tn6674 were detected and suggest the functional activity of this transposon.