Efficacy and safety of ceftazidime-avibactam versus tigecycline in the treatment of pneumonia caused by carbapenem-resistant Klebsiella pneumoniae.

BACKGROUND: Carbapenem-resistant Klebsiella pneumoniae (CRKP) causes severe high-mortality nosocomial pneumonia. Ceftazidime-avibactam (CAZ-AVI) and tigecycline (TGC) are key CRKP antimicrobials, but direct comparative efficacy and safety data are limited. This retrospective study compared clinical efficacy and safety of CAZ-AVI-based versus TGC-based regimens for CRKP pneumonia, and explored factors associated with all-cause mortality to inform clinical practice. METHODS: A total of 63 patients with CRKP pulmonary infection admitted to Shaanxi Provincial People's Hospital from January 2023 to May 2025 were retrospectively enrolled. Patients were divided into the CAZ-AVI-based regimen group (n = 33) and the TGC-based regimen group (n = 30) according to their treatment regimen. Differences in therapeutic efficacy, microbiological clearance, and adverse events between the two groups were compared, and logistic regression analysis was performed to explore factors associated with all-cause mortality. RESULTS: No statistically significant differences in baseline clinical characteristics were observed between groups (P > 0.05). Bacterial clearance rate was significantly higher in the CAZ-AVI than TGC group (72.73% vs. 36.67%, P = 0.004). No statistically significant differences were seen in clinical response, 28-day mortality, overall in-hospital mortality, superinfection, or hepatic and renal adverse events (P > 0.05). However, coagulation abnormalities (70.00% vs. 27.27%, P < 0.001) and thrombocytopenia (43.33% vs. 15.15%, P = 0.013) were significantly higher in the TGC than CAZ-AVI group. Firth penalized multivariable logistic regression identified exploratory associations of advanced age (adjusted OR = 1.12, 95% CI 1.03-1.22, P = 0.011) and comorbid diabetes mellitus (adjusted OR = 6.24, 95% CI 1.23-31.57, P = 0.027) with increased all-cause mortality. These preliminary findings warrant caution; treatment regimen showed no significant association with all-cause mortality. CONCLUSIONS: In this exploratory retrospective cohort, CAZ-AVI-based regimens were associated with a higher bacterial clearance rate and a lower incidence of coagulation and platelet abnormalities, while no statistically significant differences were observed in clinical efficacy or survival outcomes between the two regimens. Advanced age and comorbid diabetes mellitus showed exploratory associations with increased all-cause mortality, which warrant attention in clinical practice.