A Case Report and Review of the Literature: Combination Therapy with Sulbactam-Durlobactam and Meropenem for Treating Recurrent Acute Exacerbation of Chronic Obstructive Pulmonary Disease Induced by Carbapenem-Resistant Acinetobacter baumannii

Background:Acinetobacter baumannii (A. baumannii) is a leading cause of hospital-acquired pneumonia, especially in intensive care units. Carbapenem-resistant A. baumannii (CRAB) infections are associated with limited treatment options and high mortality. Sulbactam–durlobactam (SUL-DUR) is a newly approved β-lactam and β-lactamase inhibitor combination designed to target CRAB. We describe a case of recurrent CRAB pneumonia in a patient with chronic obstructive pulmonary disease (COPD) successfully managed with SUL-DUR combined with meropenem, illustrating its potential clinical utility. Case presentation:A 54-year-old man with an 8-year history of COPD presented with fever, productive cough and wheezing. Initial sputum culture grew CRAB susceptible only to polymyxin and tigecycline. After an initial inpatient response to inhaled polymyxin plus IV sulbactam, the patient relapsed two months later with recurrent CRAB pneumonia complicated by pneumothorax and empyema. Bronchoalveolar lavage and metagenomic sequencing confirmed persistent CRAB and resistance mechanisms (blaOXA-128, ADC, efflux pumps). Salvage therapy with SUL-DUR (1 g IV q6h) combined with meropenem (1 g IV q8h) was started. The patient improved rapidly: fever resolved, inflammatory markers normalized, sputum cultures became negative, chest imaging improved, and bronchoscopic secretions diminished. He was discharged after 14 days of SUL-DUR combined with meropenem and remained well at one-month follow-up. Conclusion: SUL-DUR combined with a carbapenem achieved clinical and microbiological cure in a refractory CRAB pneumonia case that failed polymyxin-based and tigecycline-based regimens. Early resistance profiling and targeted, mechanism-based combination therapy are essential for managing severe CRAB infections.