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Multi-drug-resistant Acinetobacter baumannii isolates are key pathogens that contribute to the global burden of antimicrobial resistance. This study aimed to investigate the phenotypic and molecular characteristics of carbapenem-resistant A. baumannii (CRAB) isolates from the EURECA clinical trial. In total, 228 CRAB clinical strains were recovered from 29 sites in 10 European countries participating in the EURECA study between May 2016 and November 2018. All strains were reconfirmed centrally for identification and antimicrobial susceptibility testing, and were then subjected to DNA isolation and whole-genome sequencing (WGS), with analysis performed using BacPipe v.1.2.6. K and O typing was performed using KAPTIVE. Overall, 226 (99.1%) strains were confirmed as CRAB isolates. The minimum inhibitory concentration (MIC 90 ) results of imipenem and meropenem were >16 mg/L. WGS showed that the isolates mainly harboured bla OXA-23 (n=153, 67.7%) or bla OXA-72 (n=70, 30.1%). Four bla OXA-72 isolates from Serbia co-harboured bla NDM-1. An IS5 transposase family element, ISAba31, was found upstream of the bla OXA-72 gene harboured on a small (~10-kb) pSE41030-EUR plasmid. The majority of isolates (n=178, 79.1%) belonged to international clone II. Strains belonging to the same sequence type but isolated in different countries or within the same country could be delineated in different clusters by core-genome multi-locus sequence typing (MLST). Whole-genome/core-genome MLST showed high diversity among the isolates, and the most common sequence type was ST2 (n=153, 67.7%). The EURECA A. baumannii strain collection represents a unique, diverse repository of carbapenem-resistant isolates that adds to the existing knowledge of A. baumannii epidemiology and resistance genes harboured by these strains., (Copyright © 2021 The Author(s). Published by Elsevier Ltd.. All rights reserved.)

Objectives: To investigate the diversity of plasmids that carry bla(TEM-52) genes among Escherichia coli and Salmonella enterica originating from animals, meat products and humans., Methods: A collection of 22 bla(TEM-52)-encoding plasmids was characterized by restriction fragment length polymorphism (RFLP), replicon typing (by PCR or replicon sequencing), susceptibility testing, assessment of plasmid ability to self-transfer by conjugation and typing of the genetic environment of the bla(TEM-52) gene. Detected IncI1 plasmids underwent further plasmid multilocus sequence typing., Results: RFLP profiles demonstrated dissemination of bla(TEM-52) in Denmark (imported meat from Germany), France, Belgium and the Netherlands from 2000 to 2006 by mainly two different plasmids, one encoding bla(TEM-52b) (IncX1A, 45 kb) and the other bla(TEM-52c) (IncI1, 80 kb). In addition, bla(TEM-52b) was also found to be located on various other plasmids belonging to IncA/C and IncL/M, while bla(TEM-52c) was found on IncN-like as well as on IncR plasmids. In the majority of cases (n = 21) the bla(TEM-52) gene was located on a Tn3 transposon. Seven out of 10 bla(TEM-52) plasmids tested in conjugation experiments were shown to be capable of self-transfer to a plasmid-free E. coli recipient., Conclusions: The bla(TEM-52) gene found in humans could have been transmitted on transferable plasmids originating from animal sources. Some of the bla(TEM-52) plasmids carry replicons that differ from the classical ones. Two novel replicons were detected, IncX1A and IncN-like. Unlike its predecessor bla(TEM-1), the bla(TEM-52) gene was not detected on F-type replicons suggesting that this gene evolved on other types of plasmid scaffolds.