Shahd Mohammad, Haneen Ghazal, Emadeldin El Daly, Fadi Alkhateeb, Tasnim Dawoud, Zaid Al Hassani, Aqeel Saleem, Ali Al Hassani, Thamer A Almangour
No significant differences in clinical outcomes were observed between C/A plus aztreonam and cefiderocol for C/A-resistant Enterobacterales and P. aeruginosa infections, but wide confidence intervals limited certainty. Larger molecularly characterized studies are needed to guide treatment selection.
PURPOSE: Resistance to ceftazidime-avibactam (C/A) among Enterobacterales and Pseudomonas aeruginosa limits treatment options. This study compared the effectiveness and safety of C/A plus aztreonam versus cefiderocol for C/A-resistant infections.
METHODS: This retrospective, single-center cohort study was conducted at a tertiary care hospital in the United Arab Emirates between April 1, 2022, and November 30, 2025. Eligible patients were hospitalized adults with microbiologically confirmed infections caused by C/A-resistant Enterobacterales or P. aeruginosa who received C/A plus aztreonam or cefiderocol for ≥ 48 h. The main outcomes were in-hospital mortality, 30-day mortality, and clinical cure. Additional microbiological and safety outcomes were also assessed.
RESULTS: Fifty-six patients were included, of whom 36 received C/A plus aztreonam and 20 received cefiderocol. The median age was 65 years, and 51.8% were admitted to the intensive care unit. P. aeruginosa and Klebsiella spp. were the most common targeted pathogens. No statistically significant differences were observed between treatment groups in rates of in-hospital mortality (38.9% vs. 30.0%; OR, 0.67; 95% CI, 0.21-2.17), 30-day mortality (22.2% vs. 25.0%; OR, 1.17; 95% CI, 0.32-4.20), or clinical cure (61.1% vs. 60.0%; OR, 0.95; 95% CI, 0.31-2.92). Pathogen-stratified analyses were consistent with the overall findings, with no significant between-group differences within either pathogen group. Microbiological and safety outcomes were also comparable.
CONCLUSIONS: No significant differences in clinical outcomes were observed between C/A plus aztreonam and cefiderocol for C/A-resistant Enterobacterales and P. aeruginosa infections, but wide confidence intervals limited certainty. Larger molecularly characterized studies are needed to guide treatment selection.