ICESp2905, the erm(TR)-tet(O) element of Streptococcus pyogenes, is formed by two independent integrative and conjugative elements.

In ICESp2905, a widespread erm(TR)- and tet(O)-carrying genetic element of Streptococcus pyogenes, the two resistance determinants are contained in separate fragments inserted into a scaffold of clostridial origin. ICESp2905 (∼65.6 kb) was transferable not only in its regular form but also in a defective form lacking the erm(TR) fragment (ICESp2906, ∼53.0 kb). The erm(TR) fragment was also an independent integrative and conjugative element (ICE) (ICESp2907, ∼12.6 kb). ICESp2905 thus results from one ICE (ICESp2907) being integrated into another (ICESp2906).