Treatment with Ceftazidime-Avibactam for Lower Respiratory Tract Infections Caused by the Multidrug-Resistant Gram-Negative Bacteria in the Intensive Care Unit

Abstract

Purpose: Ceftazidime avibactam (CAZ-AVI) is recommended for treating severe infections caused by multidrug-resistant gram-negative bacteria (MDR-GNB). However, there are few real-world studies on the use of CAZ-AVI to treat lower respiratory tract infections (LRTIs) caused by MDR-GNBs in intensive care units (ICUs). This study aimed to evaluate the clinical characteristics of patients with LRTIs caused by MDR-GNB who were treated with CAZ-AVI in the ICU, and to investigate the independent risk factors for mortality. Patients and Methods: This single-center retrospective study included patients with LRTIs treated with CAZ-AVI in the respiratory ICU of a tertiary hospital in Anhui Province between December 2022 and November 2024. The primary outcomes were 28-day survival and independent risk factors for all-cause mortality. Results: A total of 71 patients were enrolled in the study and 56.3% (40/71) had 28-day survival outcomes. The Acute Physiology and Chronic Health Evaluation (APACHE) II score (odds ratio [OR]: 1.144, 95% confidence interval [CI]: 1.012–1.293, p=0.032), coinfection with Aspergillus (OR: 42.753, 95% CI: 2.324–786.555, p=0.011), and days of CAZ-AVI (OR: 0.851, 95% CI: 0.734–0.986, p=0.032) were independent risk factors for 28-day all-cause mortality. Kaplan-Meier analysis demonstrated prolonged CAZ-AVI therapy (>10 days) improved survival (p<0.001), APACHE II scores >24 correlated with increased 28-day mortality (p=0.0048), and Aspergillus coinfection significantly reduced survival rates (p=0.001). We also constructed a nomogram for predicting the risk of death in ICU patients treated with CAZ-AVI for LRTIs, with good discrimination and calibration. Conclusion: CAZ-AVI can be used to treat LRTIs caused by MDR-GNB in the ICU. Higher APACHE II scores and coinfection with Aspergillus were associated with 28-day mortality, whereas a longer course of therapy was a protective factor. The nomogram can help clinicians predict CAZ-AVI outcomes.