KPC-50 Confers Resistance to Ceftazidime-Avibactam Associated with Reduced Carbapenemase Activity

Abstract

KPC-50 is a KPC-3 variant identified from a <i>Klebsiella pneumoniae</i> clinical isolate recovered in Switzerland in 2019. Compared to KPC-3, KPC-50 shows (i) a three-amino-acid insertion (Glu-Ala-Val) between amino acids 276 and 277, (ii) an increased affinity to ceftazidime, (iii) a decreased sensitivity to avibactam, explaining the ceftazidime-avibactam resistance, and (iv) an association with a sharp reduction of its carbapenemase activity.