Characterisation of carbapenemase-producing Acinetobacter baumannii isolates from danish patients 2014–2021: detection of a new international clone – IC11
Frank Hansen, Lone Jannok Porsbo, Tove Havnhøj Frandsen, Ayşe Nur Sarı Kaygısız, Louise Roer, Anna Emilie Henius, Barbara Juliane Holzknecht, Lillian Marie Søes, Kristian Schønning, Bent Røder, Ulrik Stenz Justesen, Claus Østergaard, Esad Dzajic, Mikala Wang, Nina Ank, Paul G. Higgins, Henrik Hasman, Anette M. Hammerum
Abstract
OBJECTIVES: This study aimed to characterise carbapenemase-producing Acinetobacter baumannii (A. baumannii) isolates from Danish patients using whole genome sequencing (WGS). It also compared typing and epidemiological data for further investigation of the spread and origin of the carbapenemase-producing A. baumannii isolates. METHODS: From 1 January 2014 to 30 September 2021, 141 carbapenemase-producing A. baumannii isolates, received at the national reference laboratory at Statens Serum Institut, were investigated using WGS. Multilocus sequence typing (MLST) and cgMLST data, obtained by SeqSphere+ software, were linked to data related to source of isolation, patient age and sex, hospital admission and travel history. RESULTS: (n = 124). Isolates belonging to the dominating international clone IC2 accounted for 78% of all isolates. A new international ST164/OXA-91 clone, proposed to be named IC11, was recognised and described. The cgMLST analysis revealed 17 clusters, reflecting both sporadic travel to similar geographical areas and confirmed outbreaks in Danish hospitals. CONCLUSIONS: The occurrence of carbapenemase-producing A. baumannii in Denmark was still low; however, isolates belonging to major international clones with a high potential to spread within hospitals, mainly IC2, dominated. OXA-23 was by far the most prevalent carbapenemase detected. Sporadic and travel-related introductions to Danish hospitals, also intra-hospital transmission, could be confirmed, emphasising the need for continuing vigilance.