Insertion of IS Pa1635 in IS CR1 Creates a Hybrid Promoter for bla PER-1 Resulting in Resistance to Novel β-lactam/β-lactamase Inhibitor Combinations and Cefiderocol

Abstract

Eleven bla PER-1 -positive Pseudomonas aeruginosa clinical isolates showed variable susceptibility to ceftazidime-avibactam (CZA). The genetic contexts of bla PER-1 were identical (IS CR1 - bla PER-1 - gst ) except for the ST697 isolate HS204 (IS CR1 -IS Pa1635 - bla PER-1 - gst ).