Emergence and persistent spread of carbapenemase- producing Klebsiella pneumoniae high-risk clones in Greek hospitals, 2013 to 2022

Background: Preliminary unpublished results of the survey of carbapenem-and/or colistin-resistant Enterobacterales (CCRE survey) showed the expansion of carbapenemase-producing Klebsiella pneumoniae (CPKP) sequence type (ST) 39 in 12 of 15 participating Greek hospitals in 2019. Aim: We conducted a rapid survey to determine the extent of spread of CPKP high-risk clones in Greek hospitals in 2022 and compare the distribution of circulating CPKP clones in these hospitals since 2013. Methods: We analysed whole genome sequences and epidemiological data of 310 K. pneumoniae isolates that were carbapenem-resistant or 'susceptible, increased exposure' from Greek hospitals that participated in the European survey of carbapenemaseproducing Enterobacteriaceae (EuSCAPE, 2013-2014), in the CCRE survey (2019) and in a national follow-up survey (2022) including, for the latter, an estimation of transmission events. Results: Five K. pneumoniae STs including ST258/512 (n = 101 isolates), ST11 (n = 93), ST39 (n = 56), ST147 (n = 21) and ST323 (n = 13) accounted for more than 90% of CPKP isolates in the dataset. While ST11, ST147 and ST258/512 have been detected in participating hospitals since 2013 and 2014, KPC-2-producing ST39 and ST323 emerged in 2019 and 2022, respectively. Based on the defined genetic relatedness cut-off, 44 within-hospital transmission events were identified in the 2022 survey dataset, with 12 of 15 participating hospitals having at least one within-hospital transmission event. Conclusion: The recent emergence and rapid spread of new high-risk K. pneumoniae clones in the Greek healthcare system related to within-hospital transmission is of concern and highlights the need for molecular surveillance and enhanced infection prevention and control measures.