Unveiling TCM-antibiotic synergy through multi-omics: Shuganning injection potentiates the effect of linezolid against methicillin-resistant Staphylococcus aureus.

BACKGROUND

Methicillin-resistant Staphylococcus aureus (MRSA) poses a significant threat to global public health due to its multidrug resistance, highlighting the need for the development of novel antimicrobial strategies. Computational repurposing has predicted that Shuganning injection (SGN), a clinically used hepatoprotective traditional Chinese medicine, exhibits synergistic activity with antibiotics against MRSA. However, the antimicrobial properties of SGN remain insufficiently characterized.

PURPOSE: To evaluate the anti-MRSA activity of SGN and to elucidate the mechanism underlying its synergy with linezolid (LZD).

METHODS

The components of SGN were identified using UPLC-Q/TOF-MS/MS. Antimicrobial potential was predicted through computational repurposing and validated through bactericidal and synergy assays. Biofilm inhibition, morphological changes, and cell wall integrity were assessed. Integrated metabolomics and transcriptomics were employed to investigate SGN-LZD synergy. Key findings were subsequently validated by RT-qPCR and confirmed through targeted pharmacological inhibition. Finally, in vivo efficacy was assessed in Galleria mellonella and murine skin infection models.

RESULTS

Fifty-two components were identified in SGN. Computational repurposing analysis indicated that SGN reversed sepsis-associated gene dysregulation and inhibited the growth of clinically isolated MRSA417, with corresponding MIC and MBC values of 42.5 and 170 mg/mL (crude drug equivalent), respectively. SGN demonstrated partial synergy with LZD (FICI = 0.75). The combination markedly inhibited MRSA biofilm formation by 94.25%, compared to 40.40% for SGN alone. Sub-MIC combinations caused structural damage, evidenced by increased extracellular alkaline phosphatase levels and disrupted bacterial morphology. Multi-omics analysis indicated co-downregulation of two-component system (TCS)-related metabolites (e.g., L-malic acid) and genes (saeRS, vraSR), indicating TCS suppression as the key mechanism underlying SGN-LZD synergy. The combination downregulated key TCS mRNAs. Furthermore, TCS inhibitors did not enhance its anti-biofilm and antibacterial effects. Notably, the SGN-LZD combination improved survival in G. mellonella and promoted wound healing in a murine skin infection model.

CONCLUSION

This study provides evidence supporting the repositioning of SGN for MRSA treatment. SGN impairs TCS-mediated virulence regulation, cell envelope integrity, and essential metabolic pathways, thereby enhancing the efficacy of LZD. These findings offer a translational framework for drug repurposing and highlight the clinical potential of SGN-LZD combination therapy for drug-resistant infections.