A novel plasmid-mediated PAC β-lactamase (PAC-2) variant confers resistance to ceftazidime-avibactam in Klebsiella quasipneumoniae ST526, in Colombia.

Globally, the increasing reports of resistance to ceftazidime-avibactam (CZA) in Enterobacterales are concerning. In this paper we describe an isolate of Klebsiella quasipneumoniae (GMR-RA-2034.23) highly resistant to ceftazidime-avibactam, ceftolozane-tazobactam, ceftazidime and cefotaxime in which a new variant of the PAC {beta}-lactamase, designated PAC-2 by the NCBI, was identified. The blaPAC-2 gene is encoded in a non-conjugative plasmid type IncQ (9,452 bp). The GMR-RA-2034.23 isolate did not present mutations in the OmpK35 or OmpK36 porins, associated with resistance to CZA. This is the first description of PAC-type {beta}-lactamase in Colombia. Continuous monitoring of mechanisms of resistance to CZA is crucial to prevent its spread.