Figure 1. Putative evolutionary scenario of the multidrug region of pAsa8.
Only the elements involved are shown: the gene umuC of ancestral pAsa8, the genes tnpR and the one encoding for the chemotaxis protein (CP) located on the transposon Tn1721, the insertion sequence IS5 and finally the integron In104-like. Cassettes aadA2 and qacEΔ1 are located within integron 1 of In104 (dashed arrow), and also within integron 2 of In104-like found on pAsa8 (solid line arrow) (isolate M16474-11).