Synergistic Effects of Auranofin and Lysozyme Against Staphylococcus Aureus

Antimicrobial-resistant bacteria, especially methicillin-resistant Staphylococcus aureus (MRSA) are posing a significant public health challenge. Traditional antibacterial treatments rely on external antimicrobials or their combinations to kill pathogens, yet the potential of enhancing the body’s own innate immune mechanisms as an alternative strategy has remained underexplored. As one of the most representative immune molecules, lysozyme, a widely present self-secreted antimicrobial enzyme, serves as a typical daily safeguard against infections in tissues, especially in the eyes, oral cavity and skin. Nonetheless, this defense is showing a declining trend in efficacy against MRSA. Meanwhile, the anti-rheumatic drug auranofin is being repurposed for its antibacterial effects, notably against Gram-positive bacteria. This study demonstrated that a synergistic combination of auranofin and lysozyme at physiological concentration could inhibit diverse Staphylococcus aureus growth and mitigate the risk of inducing drug-resistant mutation during continuous passages. Furthermore, this combination significantly reduced biofilm biomass. Morphological and proteomic analyses revealed that auranofin synergized with lysozyme by promoting cell wall autolysis through dysregulation of the WalRK regulatory system. This was accompanied by elevated reactive oxygen species (ROS) and depleted adenosine triphosphate (ATP). The therapeutic relevance of this synergy was confirmed in a cell-based infection model. Overall, our findings highlight the potential of auranofin as a novel adjuvant to potentiate the innate immune function of lysozyme, offering a promising approach to combat drug-resistant bacterial infections by reinvigorating the host’s inherent defense mechanisms.