Whole-plasmid analysis of NDM-1-producing Acinetobacter seifertii isolate and its fitness in several Acinetobacter species

Abstract

Objectives: The aim of this study was to characterize an NDM-1-producing Acinetobacter seifertii isolates from a patient in South Korea. Methods: Antibiotic susceptibility testing and genotyping using multigene sequencing were performed and whole plasmid sequences were determined. Results: The genotype of A. seifertii was ST1899 and was resistant to ceftazidime, trimethoprim–sulfamethoxazole, and piperacillin–tazobactam, in addition to carbapenem. blaNDM-1 was surrounded by the ISAba125 insertion sequence within the structure of Tn125 in the 47 kb-sized plasmid. The plasmid exhibited a structure similar to that of other plasmids of diverse Acinetobacter sp. found worldwide. Transconjugation and the growth curve indicated that the plasmid was adapted to A. seifertii rather than other closely related Acinetobacter sp. Conclusions: Acquisition of carbapenem resistance by horizontal transfer of the blaNDM-1-carrying plasmid from another Acinetobacter species was found with no growth defect.

Keywords

• Acinetobacter seifertii
• Carbapenemase
• NDM-1
• Tn125
• Plasmid