In vivo selection of CMY-219 conferring resistance to ceftazidime-avibactam in an OXA-484-producing E. coli ST410

Key Points

• The aim is to investigate the emergence of CMY-219, a resistance variant, to ceftazidime-avibactam in E. coli ST410.
• In vivo selection of ESBL-producing E. coli ST410
• Treatment with ceftazidime-avibactam
• Molecular analysis of resistance mechanisms
• Identification of CMY-219 variant after treatment exposure
• CMY-219 was associated with high-level resistance to ceftazidime-avibactam
• Concerns raised about the ability of ST410 and related clones to develop resistance quickly