Radical Changes in Carbapenemase-Producing Enterobacterales in Poland During the COVID-19 Pandemic and War in Ukraine

A marked increase in carbapenemase-producing Enterobacterales (CPE) occurred in Poland during COVID-19 and full-scale war in Ukraine. This study aimed to descriptively analyze the characteristics of the growing number of CPE in the country. In 2019–2024, 10,339 unique CPE isolates were collected. First, this study included an analysis of isolate and patient data. Then, 1130 Klebsiella pneumoniae isolates from July to September 2019, 2021 and 2024 were screened by PCR for hypervirulence (hvKp) genes. All PCR-positive isolates plus representative negatives ( n = 639) were sequenced and analysed with bioinformatic tools. CPE increased biphasically, with ~ 153% growth in 2019–2021 and ~ 36% in 2022–2024. During COVID-19, the increase retained the clonality and carbapenemase content of K. pneumoniae , with the predominant (> 70%) NDM-1-producing ST11 genotype, present since 2012/2013. Otherwise, in 2022–2024, the ST11 decreased to ~15%, owing to multiple clones/genotypes, including ST147, ST307 and ST395. Around 30% of the 2024 isolates carried hvKp genes. In 2022, multiple new genotypes were identified originally in Poland, Germany or elsewhere from Ukrainian patients. The study provided a recent view of CPE epidemiology in Poland and also highlighted the risk of further expansion of dangerous organisms from Eastern Europe.