Acinetobacter variabilis represents a diverse species with novel regions associated with antibiotic resistance and surface polysaccharides

<i>Acinetobacter variabilis</i> is an opportunistic pathogen found in both clinical and environmental settings with the potential to harbour and disseminate clinically significant antibiotic resistance genes. Here, we sequenced the complete genome of NGH-QLD-N1, an <i>A. variabilis</i> isolate recovered from a blood sample of a patient at Nambour General Hospital located on the Sunshine Coast region of Queensland, Australia. The assembly was used as a reference to assess the diversity in available <i>A. variabilis</i> genome sequences and investigate the genomic context of surface polysaccharide biosynthesis genes and antibiotic resistance determinants in relation to the priority pathogen, <i>Acinetobacter baumannii</i>. Phylogenetic analysis revealed substantial diversity in the species, with a distinct NGH-QLD-N1 subclade containing multiple strains with important resistance determinants. We identified a novel transposon related to the Tn<i>6022</i> family, designated Tn<i>6929</i>, that interrupted <i>comM</i> and identified multiple structural variants in <i>A. variabilis</i> genomes. Notably, some variants carried <i>bla</i> _NDM and <i>aphA6</i> in ISAba14-bounded regions, suggesting acquisition from diverse bacterial hosts. We also identified several integrative conjugative elements (ICEs) variants integrated into the chromosomal <i>thyA</i> gene, which differed in backbone structure and resistance gene content from our previously described <i>A. baumannii</i> ICE. The capsule and outer core loci for surface carbohydrate structures also had similar arrangements to those found in <i>A. baumannii</i>. This study provides a new understanding of the diversity of mobile genetic elements and ICEs carrying resistance genes, and surface polysaccharides associated with virulence, across the <i>Acinetobacter</i> genus.