Evolution of an extensively antibiotic resistant sublineage of lineage 1 of GC1 Acinetobacter baumannii
The multiply antibiotic-resistant lineage 1 of Acinetobacter baumannii global clone 1 (GC1) emerged in the 1970s, and subsequently more extensively resistant sublineages have emerged. Here, we examined the evolution of the extensively resistant MRSN56 sublineage and showed it is characterised by insertions carrying resistance genes at specific chromosomal positions. An evolved form of the sublineage carries KL17 replacing KL1 at the capsule locus and includes an additional integrative element Aci-IE1 carrying further resistance genes including bla<sub>NDM</sub>. Further members of the modified sublineage (isolated 2014-2021) identified among publicly available genomes were from several countries and appear to have replaced the original form (2007-2010). Some KL17 type isolates had acquired even more resistance genes including bla<sub>PER</sub>. The bla<sub>NDM</sub> and bla<sub>PER</sub> genes contribute to reduced susceptibility to cefiderocol and/or sulbactam/durlobactam. The phylogeny indicated that separation of the sublineage into KL1 and KL17 groups coincided with the KL switch and Aci-IE1 was acquired later.
Authors
- Christopher J. Harmer (ORCID: https://orcid.org/0000-0003-1486-454X)
- Ruth M. Hall (ORCID: https://orcid.org/0000-0003-2062-3312)
- Patrick McGann (ORCID: https://orcid.org/0000-0003-1548-9438)
- Ting L. Luo (ORCID: https://orcid.org/0000-0002-6103-1981)
- François Lebreton (ORCID: https://orcid.org/0000-0002-7157-5026)
Institutions
- The University of Sydney (AU)
- Walter Reed Army Institute of Research (US)
Publication Details
- Journal
- npj Antimicrobials and Resistance
- Published
- 2025-05-09
- DOI
- https://doi.org/10.1038/s44259-025-00103-5
- Primary Topic
- Antibiotic Resistance in Bacteria
- Type
- article
- Field-Weighted Citation Impact
- 0.00
Funders
- National Health and Medical Research Council