Establishment of an in vivo-based assay using a silkworm infection model for phenotypic evaluation of antimicrobial drug combinations against Mycobacterium abscessus.

Mycobacterium abscessus exhibits high intrinsic drug resistance, requiring combination therapy. We developed a silkworm (Bombyx mori) infection model as a whole-organism, in vivo-based platform for quantitative, outcome-based evaluations of antimicrobial combinations. The system, examined using clarithromycin-amikacin and imipenem-cefoxitin combinations, showed interaction profiles that were qualitatively consistent with those observed in vitro. This rapid, reproducible, and ethical assay enables reliable phenotypic assessments of synergistic or antagonistic effects and may facilitate the evaluation and prioritization of antimicrobial combination regimens in preclinical studies.