Large-scale WGS of carbapenem-resistant Acinetobacter baumannii isolates reveals patterns of dissemination of ST clades associated with antibiotic resistance

Sammy Frenk, Elizabeth Temkin, Mor N. Lurie-Weinberger, Alona Keren-Paz, Reut Rov, Nadya Rakovitsky, Liat Wullfhart, Amir Nutman, George L. Daikos, Anna Skiada, Emanuele Durante-Mangoni, Yael Dishon Benattar, Roni Bitterman, Dafna Yahav, Vered Daitch, Mariano Bernardo, Domenico Iossa, Oren Zusman, Lena E. Friberg, Johan W. MoutonUrsula Theuretzbacher, Leonard Leibovici, Yuval Geffen, Rina Gershon, Mical Paul, Yehuda Carmeli

Research output: Contribution to journalArticlepeer-review


Objectives: To describe the population genetics and antibiotic resistance gene distribution of carbapenem-resistant Acinetobacter baumannii (CRAB) isolates causing infections in three Mediterranean countries. Methods: Isolates were collected during the 2013-17 AIDA clinical trial in six hospitals in Israel, Greece and Italy. WGS, bioinformatic characterization and antibiotic resistance profiling were performed. Results: In the 247 CRAB isolates characterized in this study, ST distribution varied by country: 29/31 (93.5%) Greek isolates, 34/41 (82.9%) Italian isolates and 70/175 (40.0%) Israeli isolates belonged to ST2. The identified ST2 isolates included eight distinct clades: 2C, 2D and 2H were significantly more common in Italy, while 2F was unique to Greece. The uncommon ST3 was not present among Greek isolates and constituted only 5/41 (12%) Italian isolates. On the other hand, it was much more common among Israeli isolates: 78/175 (44.6%) belonged to ST3. The vast majority of isolates, 240/247 (97.2%), were found to harbour acquired carbapenemases, primarily blaOXA-23. The chromosomal oxaAb (blaOXA-51-like) and ampC genes characteristic of this organism were also ubiquitous. Most (96.4%) ST3 isolates carried a broad-host-range plasmid IncP1α. Conclusions: The geographical differences in CRAB populations support the theory that clonal spread of CRAB leads to endemicity in hospitals and regions. The close association between antibiotic resistance genes and clades, and between plasmids and STs, suggest that de novo creation of MDR A. baumannii is rare. The clustering of antibiotic resistance genes and plasmids that is unique to each clade/ST, and nearly uniform within clades/STs, suggests that horizontal transmission is rare but crucial to the clade's/ST's success.

Original languageEnglish
Pages (from-to)934-943
Number of pages10
JournalJournal of Antimicrobial Chemotherapy
Issue number4
StatePublished - 31 Mar 2022
Externally publishedYes

Bibliographical note

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© 2022 The Author(s) 2022. Published by Oxford University Press on behalf of British Society for Antimicrobial Chemotherapy. All rights reserved. For permissions, please e-mail:

ASJC Scopus subject areas

  • Microbiology (medical)
  • Pharmacology (medical)
  • Infectious Diseases
  • Pharmacology


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