Multidrug-resistant Gram-negative bacteria (MDR-GNB) is emerging globally as a pathogen of concern in healthcare-associated infections (HAIs), and a threat to public health.There has been an alarming rise in the prevalence of MDR-GNB infections globally over the last decade.Multidrug-resistant or Carbapenem-resistant Pseudomonas aeruginosa (MDRPA or CRPA) are one of the major pathogens in the hospital setting,and are particularly challenging due to limited therapeutic options,associated with high mortality rates.Ceftazidime/avibactam(CAZ/AVI) combines the anti-pseudomonal cephalosporin ceftazidime and the novel non-β-lactam β-lactamase inhibitor avibactam,which are now available for the treatment of MDR-GNB infections and favorable outcomes have been reported in hospitalized patients with carbapenem-resistant Enterobacterales (CRE).However, there are only few publications available with a small sample size limit, focusing on the efficacy of CAZ/AVI for the treatment of CRPA or MDRPA infections.Therefore, a retrospective analysis was conducted to compare the clinical efficacy and microbiological efficacy of CAZ/AVI versus other antibiotics for the treatment of MDRPA infections.

Inclusion Criteria:

• patients with MDRPA infection diagnosed by clinicians
• patients treated with anti-Pseudomonas aeruginosa antibiotics for at least 72h
• patients older than 18 years old.

Exclusion Criteria:

• Patients with human immunodeficiency virus infection, mental illness, a medication course of less than 72 hours, or incomplete data were excluded.

This was a single-centre, retrospective and observational study conducted in the First Affiliated Hospital of Nanjing Medical University, a 2200-bed tertiary care teaching hospital in Nanjing, Jiangsu in China, from January 2019 to April 2023.The inclusion criteria consisted of (i) patients with MDRPA infection diagnosed by clinicians,(ii) patients treated with anti-Pseudomonas aeruginosa antibiotics for at least 72h,(iii) patients older than 18 years old. Patients with human immunodeficiency virus infection, mental illness, a medication course of less than 72 hours, or incomplete data were excluded.