Identification of AbaR4 #Acinetobacter baumannii #resistance island in clinical isolates of blaOXA-23-positive #Proteus mirabilis (J Antimicrob Chemother., abstract)

[Source: Journal of Antimicrobial Chemotherapy, full page: (LINK). Abstract, edited.]

Identification of AbaR4 Acinetobacter baumannii resistance island in clinical isolates of blaOXA-23-positive Proteus mirabilis

Sophie Octavia, Weizhen Xu, Oon Tek Ng, Kalisvar Marimuthu, Indumathi Venkatachalam, Bernadette Cheng, Raymond T P Lin, Jeanette W P Teo

Journal of Antimicrobial Chemotherapy, dkz472,

Published: 14 November 2019




blaOXA-23 is a class D carbapenemase-encoding gene typical of the Acinetobacter genus. However, its occurrence in the Enterobacteriaceae is uncommon. Here we provide the genome characterization of blaOXA-23-positive Proteus mirabilis.


In Singapore, a national surveillance of carbapenem non-susceptible clinical Enterobacteriaceae has enabled the collection of OXA-23 bearing isolates. Three clinical P. mirabilis were whole-genome sequenced using Oxford Nanopore MinION and Illumina platforms. The sequence accuracy of MinION long-read contigs was enhanced by polishing with Illumina-derived short-read data.


In two P. mirabilis genomes, blaOXA-23 was detected as two copies, present on the chromosome and on a 60 018 bp plasmid. blaOXA-23 was associated with the classic Acinetobacter composite transposon Tn2006, bounded by two copies of ISAba1 bracketing the carbapenemase gene. The Tn2006 itself was embedded within an Acinetobacter baumannii AbaR4 resistance island. In the chromosome, the AbaR4 was found integrated into the comM gene, which is also the preferred ‘hotspot’ in A. baumannii. In the plasmid, AbaR4 integrated into a putative colicin gene.


Our description of an A. baumannii AbaR4 encoding blaOXA-23 in P. mirabilis is to our knowledge the first description of an Acinetobacter resistance island in Proteus and suggests that P. mirabilis may be a reservoir for this class D carbapenemase gene.


© The Author(s) 2019. Published by Oxford University Press on behalf of the British Society for Antimicrobial Chemotherapy. All rights reserved. For permissions, please email:

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Keywords: Antibiotics; Drugs Resistance; Carbapenem; Acinetobacter baumannii; Proteus mirabilis; Singapore.


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Giuseppe Michieli

I am an Italian blogger, active since 2005 with main focus on emerging infectious diseases such as avian influenza, SARS, antibiotics resistance, and many other global Health issues. Other fields of interest are: climate change, global warming, geological and biological sciences. My activity consists mainly in collection and analysis of news, public services updates, confronting sources and making decision about what are the 'signals' of an impending crisis (an outbreak, for example). When a signal is detected, I follow traces during the entire course of an event. I started in 2005 my blog ''A TIME'S MEMORY'', now with more than 40,000 posts and 3 millions of web interactions. Subsequently I added an Italian Language blog, then discontinued because of very low traffic and interest. I contributed for seven years to a public forum ( in the midst of the Ebola epidemic in West Africa in 2014, I left the site to continue alone my data tracking job.