Genetic structures of blaOXA-23-containing elements. The structure of Tn2007, which has not been proven to transpose, is shown on top. Tn2008 and Tn2008B differ in the number of nucleotides (27 and 34, respectively) that separate blaOXA-23 from ISAba1. Tn2006, the only structure experimentally shown to transpose [178], includes copies of ISAba1 in opposite orientations, while Tn2009 carries these insertion sequences in the same orientation. These two transposons are the only ones with the typical composite transposon structure. An extensive and detailed description of these elements was recently published [177]. ATPase*, gene coding for a putative ATPase truncated at the N-terminus. DADE, gene coding for a putative DEAD box family helicase [181]. Figure interpreted from Nigro and Hall (2016) [177].