The promise and pitfalls: interpreting dual β-lactam success in Mycobacterium abscessus with caution

Mycobacterium abscessus complex (MABSC) poses significant therapeutic challenges and is associated with poor clinical outcomes. There is an urgent need for safer, more effective, and evidence-based treatment options. Dual β-lactam (DBL) therapy has demonstrated promising in vitro synergy, and emerging case reports suggest potential benefit as a salvage therapy. Shimamura et al. (ASM Case Rep 1:e00087-24, 2025, https://doi.org/10.1128/asmcr.00087-24) describe two pediatric cases with MABSC pulmonary disease that achieved successful outcomes following the addition of DBL to the treatment regimen. However, the integration of DBL into clinical practice remains challenging due to the lack of standardized synergy testing, limited in vivo data, and poorly characterized pharmacodynamics of various DBL combinations at the site of infection. While DBL represents a promising addition to the therapeutic armamentarium for MABSC, its clinical use should be guided by careful appraisal of the currently limited and potentially biased clinical evidence. The paucity of high-certainty data highlights the need for systematic data collection through collaborative multicenter registries and clinical trials to rigorously evaluate the efficacy and safety of DBL regimens.