Detection in two hospitals of transferable ceftazidime-avibactam resistance in Klebsiella pneumoniae due to a novel VEB β-lactamase variant with a Lys234Arg substitution, Greece, 2019.

Two ceftazidime-avibactam (CAZ-AVI)-resistant Klebsiella pneumoniae carbapenemase (KPC)-positive K. pneumoniae strains, including one pandrug resistant, were isolated in 2019 from two Greek hospitals. The strains were sequence types (ST)s 258 and 147 and both harboured similar self-transmissible IncA/C2 plasmids encoding a novel Lys234Arg variant of the Vietnamese extended-spectrum β-lactamase (VEB)-1, not inhibited by AVI (VEB-25). Conjugal transfer of VEB-25-encoding plasmids to Escherichia coli yielded CAZ-AVI-resistant clones, supporting that VEB-25 is directly linked to the derived phenotype.