Emergence of ceftazidime-avibactam resistance in Klebsiella pneumoniae. Klebsiella pneumoniae subsp. pneumoniae

Avibactam is a novel β-lactamase inhibitor that inactivates KPCs, as well as OXA-48 carbapenemases, and AmpC and extended spectrum β-lactamases (ESBL). It was approved in 2015 by the U. S. Food and Drug Administration for treatment of complicated intra-abdominal infections (in conjunction with metronidazole) and urinary tract infections. We present clinical cases in which ceftazidime-avibactam resistance emerged during treatment of carbapenem-resistant K. pneumoniae infections.