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

Abstract

ABSTRACT 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-Tn 4401 -element harboring an aac (3)-IId-bla TEM-1B - bla KPC-2 –cassette (designated NTE KPC -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. IMPORTANCE Current infection control protocols assume that the spread of KPC-2 carbapenemase-producing Enterobacterales ( KPC2-CPE) by detected carriers to other in-house patients is through clonal transmission and can be restricted by implementing containment measures. We examined the presence of the bla KPC-2 gene in different genera and species of Enterobacterales isolated from humans at different hospitals and surface waters between 2013 and 2019 in Germany. We found that a single IncN[pMLST15] plasmid carrying the bla KPC-2 gene on a novel non-Tn 4401 -element (NTE KPC -Y), flanked by an adjacent region encoding 12 other antibiotic resistance genes, was uniquely present in multiple species of KPC2-CPE isolates. These findings demonstrate the selective impact of specific IncN plasmids as major drivers of carbapenemase dissemination and suggest “plasmid-based endemicity” for KPC2-CPE. Studies on the dynamics of plasmid-based KPC2-CPE transmission and its presence in persistent reservoirs need to be urgently considered to implement effective surveillance and prevention measures in healthcare institutions.