Klebsiella pneumoniae is one of the most common pathogens of pneumonia and bloodstream infections worldwide. To make matters more complicated, these bacteria are often resistant to most antibiotics. The novel antibiotic Cefiderocol, which was first authorised in the USA in 2019 (2020 in Germany), should be a promising approach in the fight against multi-resistant K. pneumoniae. Together with experts in microbiological diagnostics, the team from the Department of EPIDEMIOLOGY AND ECOLOGY OF ANTIMICROBIAL RESISTANCE, led by Prof Katharina Schaufler, investigated cefiderol-resistant K. pneumoniae strains that were isolated prior to the clinical use of this antibiotic as part of a clinical outbreak in Mecklenburg-Western Pomerania: "Convergent Klebsiella pneumoniae strains belonging to a sequence type 307 outbreak clone combine cefiderocol and carbapenem resistance with hypervirulence". This study by the Helmholtz Institute for One Health (HIOH), a site of the Helmholtz Centre for Infection Research (HZI), underlines the clinical relevance of emerging antibiotic resistance and the need to develop new treatment options. It also shows how important it is to understand the evolution of resistance development in order to ensure the effectiveness of new antibiotics in the future.