Whole-Genome Sequencing and Molecular Analysis of Ceftazidime–Avibactam-Resistant KPC-Producing Klebsiella pneumoniae from Intestinal Colonization in Elderly Patients

Ceftazidime–avibactam (CAZ-AVI) is an active antibiotic combination of a β-lactam–β-lactamase inhibitor against carbapenemase-producing Enterobacterales. Reports resistance to CAZ-AVI other than metallo-β-lactamases have increased in recent years. The aim this study was analyze KPC-Klebsiella pneumoniae (KP) isolates resistant from the intestinal carriage hospitalized elderly patients Italy, February 2018–January 2020. Characterization CAZ-AVI-resistant KP isolates, including MLST, resistome, virulome and plasmid content, performed by WGS analysis. Out six three belonged ST101 ST512; two produced KPC-3 (both ST512), four had mutated (KPC-31, ST512, KPC-46, both ST101). All were multidrug-resistant carried several genes. yersiniabactin ybt9 gene cluster present all while, ST512 no virulence genes detected. Several plasmids detected: IncF as well IncR Col440 IncX3 isolates. In conclusion, it important monitor circulation K. prevent spread clones causing difficult-to-treat infections. presence high-risk deserves attention.