Efficacies of Colistin–Carbapenem versus Colistin–Tigecycline in Critically Ill Patients with CR-GNB-Associated Pneumonia: A Multicenter Observational Study

Background: Evaluating the options for antibiotic treatment for carbapenem-resistant Gram-negative bacteria (CR-GNB)-associated pneumonia remains crucial. We compared the therapeutic efficacy and nephrotoxicity of two combination therapies, namely, colistin + carbapenem (CC) versus colistin + tigecycline (CT), for treating CR-GNB-related nosocomial pneumonia in critically ill patients. Methods: In this multicenter, retrospective, and cohort study, we recruited patients admitted to intensive care units and diagnosed with CR-GNB-associated nosocomial pneumonia. We divided the enrolled patients into CC (n = 62) and CT (n = 59) groups. After propensity score matching (n = 39), we compared the therapeutic efficacy by mortality, favorable outcome, and microbiological eradication and compared nephrotoxicity by acute kidney injury between groups. Results: There was no significant difference between the CC and CT groups regarding demographic characteristics and disease severities as assessed using the Acute Physiology and Chronic Health Evaluation (APACHE) II score, Sequential Organ Failure Assessment (SOFA) score, and other organ dysfunction variables. Therapeutic efficacy was non-significantly different between groups in all-cause mortality, favorable outcomes, and microbiological eradication at days 7, 14, and 28; as was the Kaplan-Meier analysis of 28-day survival. For nephrotoxicity, both groups had similar risks of developing acute kidney injury, evaluated using the Kidney Disease Improving Global Outcomes criteria (p = 1.000). Conclusions: Combination therapy with CC or CT had similar therapeutic efficacy and risk of developing acute kidney injury for treating CR-GNB-associated nosocomial pneumonia in critically ill patients.