Distribution of intrinsic plasmid replicase genes and their association with carbapenem-hydrolyzing class D beta-lactamase genes in European clinical isolates of Acinetobacter baumannii

Kevin J Towner, Benjamin Evans, Laura Villa, Katrina Levi, Ahmed Hamouda, Sebastian G B Amyes, Alessandra Carattoli

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Ninety-six genetically diverse multidrug-resistant clinical isolates of Acinetobacter baumannii from 25 hospitals in 17 European countries were screened by PCR for specific carbapenemase-hydrolyzing class D β-lactamase (CHDL) genes and by PCR-based replicon typing for the presence of 19 different plasmid replicase (rep) gene homology groups (GRs). Results were confirmed by DNA sequencing where necessary. All 96 isolates contained at least 1 (with a maximum of 4) of the 19 groups of rep genes. Groups detected were GR6 (repAci6; 93 isolates), GR2 (including repAci1 [67 isolates] and repAci2 [3 isolates]), GR16 (repApAB49; 12 isolates), GR12 (p2ABSDF0001; 10 isolates), GR3 (repAci3; 4 isolates), GR4 (repAci4; 3 isolates), GR10 (repAciX; 1 isolate), and GR14 (repp4AYE; 1 isolate). Variations in rep gene content were observed even among epidemiologically related isolates. Genes encoding OXA-58-like CHDLs (22 isolates) were associated with carriage of the repAci1, repAci3, repAci4, and repAciX genes, genes encoding OXA-40-like CHDLs (6 isolates) were associated with repAci2 and p2ABSDF0001, and genes encoding OXA-23-like CHDLs (8 isolates) were associated with repAci1. Most intrinsic Acinetobacter plasmids are non-self-transferable, but the almost ubiquitous repAci6 gene was strongly associated with a potential tra locus that could serve as a general system for plasmid mobilization and consequent horizontal transmission of plasmids and their associated antibiotic resistance genes among strains of A. baumannii.

Original languageEnglish
Pages (from-to)2154-2159
Number of pages6
JournalAntimicrobial Agents and Chemotherapy
Issue number5
Early online date7 Feb 2011
Publication statusPublished - May 2011


  • Acinetobacter baumannii
  • Carbapenems
  • Plasmids
  • beta-Lactamases

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