Predominant transmission of KPC-2 carbapenemase in Germany by a unique IncN plasmid variant harboring a novel non-transposable element (NTE_KPC-Y)

Carbapenemase-producing Enterobacterales (CPE) pose a major public health threat. Despite active infection prevention efforts, the incidence of KPC-2 carbapenemase-producing Enterobacterales (KPC2-CPE) continues to increase worldwide. In this study, we performed genome sequencing of 135 KPC2-CPE isolates obtained from multiple sources (clinical, hospital environments, and surface water) in Germany between 2013 and 2019 and analyzed them for epidemiological clues regarding transmission. For 92% (124/135) of all isolates, which comprised 14 different species such as Klebsiella, Escherichia, Citrobacter, Enterobacter, Raoultella, and Serratia, KPC-2 was present on an IncN[pMLST15] plasmid. All plasmids carried a novel non-Tn4401-element harboring an aac (3)-IId-bla(TEM-1B)-bla(KPC-2)-cassette (designated NTEKPC-Y) that was co-transferred with an adjacent region carrying 12 further antibiotic resistance genes. Identical plasmids were also detected in KPC2-CPE isolates from environmental samples. These plasmids were remarkably stable and were maintained in individual patients colonized with KPC-2 CPEs over a long-term period (>1 year). Thus, a predominant broad host range signature IncN[pMLST15] plasmid mediates transmission of both KPC-2 and associated multiple antimicrobial drug resistance genes in Germany. These data underline the need for in-depth characterization of plasmid carriers of CPE in surveillance and outbreak studies as well as in microbiomes from patients and the environment to identify hidden transmission reservoirs. This information will be essential for the development and implementation of effective infection control and prevention measures to disrupt dissemination of KPC2- CPEs in healthcare and associated environmental settings.