Within-patient horizontal transfer of pOXA-48 from a hypervirulent Klebsiella pneumoniae SL218 to Serratia marcescens following spread of the K. pneumoniae isolate among hospitalised patients, Denmark, 2021.

A hypervirulent SL218 (ST23-KL57), phylogenetically distinct from the classical hypervirulent SL23 (ST23-KL1) lineage, was transmitted between hospitalised patients in Denmark in 2021. The isolate carried a hybrid resistance and virulence plasmid containing and a plasmid containing (pOXA-48); the latter plasmid was horizontally transferred within-patient to . The convergence of drug resistance and virulence factors in single plasmids and in different lineages of is concerning and requires surveillance.