Reviewed by Jose A. Lucar, MD, FIDSA, The George Washington University
Combining sulbactam with avibactam significantly enhances activity against carbapenem-resistant Acinetobacter baumannii (CRAB), offering a promising therapeutic option where conventional regimens often fail. A study by Arun et al. showed that avibactam restores sulbactam’s efficacy against resistant strains through synergistic effects, supported by in vitro time-kill assays and pharmacokinetic/pharmacodynamic modeling (1). This strategy addresses the urgent need for alternatives to polymyxins, carbapenems, and even cefiderocol in settings of escalating resistance. Previous case reports have explored this approach: a pediatric burn patient achieved clearance of MDR A. baumannii using ceftazidime/avibactam plus ampicillin/sulbactam after multiple prior regimen failures, while a burn ICU outbreak report documented partial success with the same combination in critically ill patients (2, 3). In Arun et al.’s study, CRAB isolates harboring blaOXA-23, blaNDM-1, or both were resistant to either agent alone, but the combination achieved up to 90% bacterial reduction. Modeling based on resistance gene profiles revealed higher dose requirements for strains containing blaNDM-1. Limitations include the in vitro design, small number of strains tested, and lack of clinical data, underscoring the need for observational studies and prospective trials to confirm efficacy and safety. These results highlight the clinical potential of sulbactam/avibactam and the importance of integrating genetic resistance data into dosing strategies.
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