Outcome of Ceftazidime/Avibactam Versus Alternative Antibiotics for Treatment of Carbapenem-Resistant Enterobacterales Bacteremia in Patients With Hematologic Malignancies.

BACKGROUND: Until recent introduction of ceftazidime/avibactam (CAZ-AVI) to Korean hospitals in October 2023, alternative antibiotics had been used to treat carbapenem-resistant Enterobacterales (CRE) infection such as high-dose meropenem combination therapy with amikacin, tigecycline, and/or colistin. To compare the outcome of CRE bacteremia between CAZ-AVI (study group) and alternative antibiotics (comparator group) before/after the introduction of CAZ-AVI. METHODS: We retrospectively reviewed the adult patients with hematologic malignancy who had CRE bacteremia between January 2020 and July 2024. RESULTS: A total of 85 patients with CRE bacteremia were analyzed including 25 with CAZ-AVI and 60 with alternative antibiotics. In a time-dependent multivariable Cox model for negative conversion of bacteremia, CAZ-AVI (hazard ratio [HR], 2.475; 95% confidence interval [CI], 1.493-4.102; P < 0.001) and Klebsiella pneumoniae carbapenemase [KPC] (HR, 0.490; 95% CI, 0.296-0.810; P = 0.005) was independently associated with rapid negative conversion. CAZ-AVI was associated with rapid negative conversion of bacteremia in the inverse probability of treatment weighting (IPTW) analysis (HR, 3.030; 95% CI, 1.818-5.263; P < 0.001). In a time-dependent multivariable Cox model, CAZ-AVI was the only independent predictor for 30-day mortality (HR, 0.295; 95% CI, 0.087-0.996; P = 0.049), although CAZ-AVI did not reach any statistical significance for 30-day mortality (HR, 0.513; 95% CI, 0.146-1.804; P = 0.298) in IPTW analysis. CONCLUSION: CAZ-AVI showed higher rapid negative conversion for CRE bacteremia in patients with hematologic malignancy, compared to the alternative antibiotics.