P-1496. Retrospective Study of Ceftazidime-Avibactam Treatment for Multidrug-Resistant Gram-Negative Bacterial Infections in King Chulalongkorn Memorial Hospital

Abstract Background Antimicrobial resistance, particularly among Enterobacterales, poses a significant healthcare threat. With the rise of carbapenem-resistant strains, alternative treatment strategies are necessary. This study explores the clinical experience of using ceftazidime-avibactam (CAZ-AVI) in treating infections caused by multidrug-resistant Gram-negative bacteria (MDR-GNB), including carbapenem-resistant pathogens.Table 1.Baseline characteristics of the patients who received CAZ/AVI Methods A single-center retrospective observational study was conducted at King Chulalongkorn Memorial Hospital, Thailand, from Jan. 2019 to Dec. 2022. The study included adult patients aged ≥18 years, who receiving ≥48 hours of CAZ-AVI for documented MDR-GNB infections. Data on demographics, comorbidities, treatment regimens, and outcomes were extracted from electronic medical records. The primary outcome was all-cause mortality at 14 days. Secondary objectives included clinical and microbiological responses at 14 days, and all-cause mortality at 28 days.Table 2.Clinical outcomes of the patients who received CAZ/AVI Results Among 85 patients receiving CAZ-AVI, 75 met inclusion criteria. The mean age was 65.27 years, with 54.7% being male. Hospital-acquired infections accounted for 82.7%, and 56% were ICU patients. Underlying conditions included chronic kidney diseases/end-stage renal diseases (28%), solid tumors (24%), cirrhosis (13.3%), hematologic malignancies (10.7%), and solid organ transplantation (10.7%). K. pneumoniae was the most common organism (69.3%), followed by P. aeruginosa (20%). All (100%) of K. pneumoniae and E. coli were carbapenem resistance. CAZ-AVI susceptibility was observed in 93.6% of isolates. The 14-day all-cause mortality rate was 25.3%. Clinical and microbiological response rates were 70.7% and 65.3%, respectively. Infection by CAZ-AVI-susceptible organisms correlated with lower mortality rates (p=0.017). No adverse drug effects were reported.Table 3.Clinical outcomes of the patients who received CAZ/AVI Conclusion This study highlights the promising role of CAZ-AVI in treating MDR-GNB infections, offering an alternative to conventional therapies. While challenges remain, including the complexity of empirical therapy and variations in patient outcomes, CAZ-AVI demonstrates efficacy with a favorable safety profile. Disclosures KAMONWAN JUTIVORAKOOL, MD, Msc, Pfizer, Thailand: Grant/Research Support|Pfizer, Thailand: Honoraria Rongpong Reinprayoon, MD, MSc, Pfizer: Grant/Research Support