I was involved (extremely) peripherally in some work on chromosomal resistance islands in Acinetobacter baumannii by Prof Ruth Hall’s team at the University of Sydney, and part of that work has just been published. Basically, the team was investigating a 16S ribosomal RNA methyltransferase gene armA that conveys resistance to a broad array of aminoglycosides (including gentamicin and amikacin), and which is carried in a special “resistance island” (so-called because antibiotic resistance genes are aggregated together)  AbGRI3 in the chromosome of certain A. baumannii isolates.

Thanks to the assistance of the 10minus6cosm blogger, we were able to send 20 extensively-drug resistant (XDR) A. baumannii isolates belonging to Global Clone 2 that were obtained from patient samples between 1996 and 2011 to Prof Hall’s laboratory, where the armA gene was found in 15 isolates. Interestingly, the gene was found in 5 different variants of the genomic resistance island (AbGRI3) that typically contains armA, suggesting multiple introductions into Singapore over time.

Screen capture of a figure from the journal article, comparing various versions of the genomic resistance island AbGRI3 carrying armA in Singapore isolates.

Many thanks to Dr Grace Blackwell and Prof Ruth Hall completing the work, and to Prof Kathryn Holt (Holt Lab, University of Melbourne) as well as Prof Stephen Bentley (Wellcome Trust Sanger Institute) for the support, and for the initial assembling of the group working on A. baumannii genomics.