J Bacteriol Virol.  2015 Mar;45(1):51-53. 10.4167/jbv.2015.45.1.51.

ISAba15 Inserted into Outer Membrane Protein Gene carO in Acinetobacter baumannii

  • 1Department of Molecular Cell Biology, Samsung Biomedical Research Institute, Sungkyunkwan University School of Medicine, Suwon, Korea. ksko@skku.edu


We identified ISAba15 inserted into the carO gene in an Acinetobacter baumannii isolate. The insert disrupted the lpxD gene, resulting in colistin resistance in A. baumannii. Persistence in carbapenem resistance in A. baumannii isolates with an intact carO gene indicates that loss of the encoded CarO may play a minor role in carbapenem resistance.


Carbapenem; Insertion sequence (IS); Antimicrobial resistance

MeSH Terms

Acinetobacter baumannii*
Drug Resistance, Bacterial
Membrane Proteins*
Membrane Proteins


  • Figure 1. Schematic representation of the genetic organization of ISAba15 interrupting the carO gene in A. baumannii isolate 07AC-017. IRR, right inverted repeats; IRL, left inverted repeats; DR, direct repleat.

  • Figure 2. CarO expression levels in two ST92 A. baumannii isolates. While 07AC-007 is an isolate with intact carO gene, 07AC-017 had carO gene interrupted by ISAba15. mRNA levels were normalized to RpoB expression levels.


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