Successive Emergence of Ceftazidime-Avibactam Resistance through Distinct Genomic Adaptations in bla KPC-2 -Harboring Klebsiella pneumoniae Sequence Type 307 Isolates

variants. These results raise concerns about the strong selective pressures incurred by novel carbapenemase inhibitors, such as avibactam, on isolates previously considered invulnerable to CAZ-AVI resistance. There is an urgent need to further characterize non-KPC-mediated modes of carbapenem resistance and the intrinsic bacterial factors that facilitate the rapid emergence of resistance during treatment.