Impact of Ceftazidime-Avibactam Treatment in the Emergence of Novel KPC Variants in the ST307-Klebsiella pneumoniae High-Risk Clone and Consequences for Their Routine Detection
Marta Hernández-García, Juan Antonio Castillo-Polo, Desirée Cordero, Blanca Pérez-Viso, María García-Castillo, Javier Sáez de la Fuente, María Isabel Morosini, Rafael Cantón, Patricia Ruíz-Garbajosa
Abstract
genes was confirmed in the K. pneumoniae isolates with increased CAZ/AVI MICs and restored carbapenem activity. KPC production was confirmed by immunochromatography, the eazyplex Superbug CRE system, and the Xpert Carba-R assay in all KPC K. pneumoniae isolates, but not in any isolate using chromogenic agar plates for carbapenemase producers (ChromID-CARBA), the KPC/MBL/OXA-48 Confirm kit, and the β-CARBA test. Nevertheless, all grew in chromogenic agar plates for extended-spectrum β-lactamase (ESBL) producers (ChromID-ESBL). We report the failure of the most common phenotypic methods used for the detection of novel KPC carbapenemases but not of rapid molecular or immunochromatography assays, thus highlighting their relevance in microbiology laboratories.