Strains used in this study and their characteristics.

nd: not determined.
* Numbers of antimicrobial agents to which an isolate was resistant using disc diffusion with 10 antimicrobial agents.
** Resistance to at least one representative of 3 or more of the 5 classes of antimicrobial agents, i.e. beta-lactams (piperacillin, ceftazidime, ampicillin-sulbactam, imipenem), aminoglycosides (gentamicin, amikacin, tobramycin), fluoroquinolones (ofloxacin), tetracyclines (tertracycline) and the combination of sulfonamide and diaminopyriminide (sulfamethoxazol + trimethoprim).
*** Multiple isolates of outbreak 1–7 were analyzed in the current study to check for reproducibility and concordance (see text); only one strain per outbreak was included in the table.
**** The genome of seven A. baumannii strains was fully sequenced (ATCC 17978, AYE, SDF, ACICU, AB0057, AB307-0294 and AB900). For these strains, sequences were extracted from the genome sequence.
***** According to previous publications; criteria may differ from those used for the strains analysed in this work.