Successful Treatment of Carbapenem-Resistant Acinetobacter baumannii Infection with Sulbactam-Durlobactam: A Two-Case Report.

BACKGROUND: Sulbactam-Durlobactam (SUL-DUR), a novel β-lactam/β-lactamase inhibitor combination, exhibits potent activity against Acinetobacter baumannii isolates, including carbapenem-resistant Acinetobacter baumannii (CRAB). Current guidelines recommend SUL-DUR in combination with imipenem-cilastatin or meropenem for the treatment of CRAB pneumonia. However, clinical evidence regarding its use in CRAB bloodstream infections remains limited, and the role of SUL-DUR monotherapy in CRAB pneumonia remains unclear. METHODS: We describe two critically ill patients with severe CRAB infections who were successfully treated with SUL-DUR. Clinical characteristics, microbiological findings, antimicrobial regimens, treatment responses, and clinical outcomes were reviewed. The rationale for selecting combination therapy or monotherapy was described according to infection characteristics and individual clinical considerations. RESULTS: The first patient developed CRAB bloodstream infection following severe trauma and was successfully treated with SUL-DUR combined with imipenem-cilastatin, achieving rapid clearance of blood cultures and clinical improvement. The second patient developed CRAB pneumonia in the context of pulmonary Aspergillus fumigatus infection requiring antifungal therapy. Considering the absence of concurrent bacterial pathogens and concerns regarding additional broad-spectrum antimicrobial exposure, SUL-DUR monotherapy was selected as an individualized treatment strategy and resulted in resolution of fever, improvement of pulmonary lesions, and successful ventilator liberation. CONCLUSION: These two cases expand the clinical experience of SUL-DUR in severe CRAB infections, demonstrating successful treatment of CRAB bloodstream infection with SUL-DUR-based combination therapy and favorable outcomes of individualized SUL-DUR monotherapy for selected monomicrobial CRAB pneumonia.