Ceftazidime-avibactam resistance evolution in Pseudomonas aeruginosa and implications for cross-resistance to other novel β-lactams

Antimicrobial Agents and Chemotherapy 2026 Open access

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Authors: Ava J Dorazio, Ellen G Kline, Kevin M Squires, Sunish Shah, Daria Van Tyne, Janet Y. Wu, Jason M. Pogue, Ryan K. Shields
DOI: 10.1128/aac.01910-25
Cited by: 2
References: 29

Abstract

ABSTRACT Twelve pairs of baseline and post-exposure Pseudomonas aeruginosa isolates from patients treated with ceftazidime-avibactam were evaluated to define mechanisms of treatment-emergent resistance. Resistance was associated with amino acid substitutions in ampC and OXA β-lactamases, or mutations in regulatory genes conferring hyper-production of AmpC and MexAB-OprM efflux pumps. Cross-resistance was common between ceftazidime-avibactam and ceftolozane-tazobactam, less common for imipenem-relebactam and cefepime-zidebactam, and lowest for cefiderocol. These findings have important implications for sequential treatment of P. aeruginosa infections.

Fields of Study & Subjects

Antibiotic Resistance in Bacteria Pneumonia and Respiratory Infections Antibiotics Pharmacokinetics and Efficacy

Publication details

Journal / source
Antimicrobial Agents and Chemotherapy
Publisher
American Society for Microbiology
Volume
70
Issue
5
Pages
e0191025–e0191025
Publication date
6 April 2026
Language
EN