Nanopore MinION Sequencing Reveals Possible Transfer ofblaKPC-2Plasmid Across Bacterial Species in Two Healthcare Facilities

Carbapenemase-producingEnterobacteriaceaeare a major threat to global public health.Klebsiella pneumoniaecarbapenemase (KPC) is the most commonly identified carbapenemase in the United States and is frequently found on mobile genetic elements including plasmids, which can be horizontally transmitted between bacteria of the same or different species. Here we describe the results of an epidemiological investigation of KPC-producing bacteria at two healthcare facilities. Using a combination of short-read and long-read whole-genome sequencing, we identified an identical 44 kilobase plasmid carrying thebla(KPC-2)gene in four bacterial isolates belonging to three different species (Citrobacter freundii,Klebsiella pneumoniae, andEscherichia coli). The isolates in this investigation were collected from patients who were epidemiologically linked in a region in which KPC was uncommon, suggesting that the antibiotic resistance plasmid was transmitted between these bacterial species. This investigation highlights the importance of long-read sequencing in investigating the relatedness of bacterial plasmids, and in elucidating potential plasmid-mediated outbreaks caused by antibiotic resistant bacteria.