Overcoming methicillin resistance in Staphylococcus aureus via metal ion disruption of bacterial metabolism.

Methicillin-resistant Staphylococcus aureus (MRSA) is a significant public health threat due to both extensive antimicrobial resistance and immune evasion capabilities, necessitating alternative therapeutic strategies. Disruption of bacterial metal ion homeostasis, a process already leveraged by host nutritional immunity, represents a promising therapeutic approach. The synthetic ionophore PBT2 delivers zinc (Zn) directly into the bacterial cytosol, where it can dysregulate cellular processes and restore the efficacy of conventional antibiotics. Here, we use PBT2 and Zn (PZ) to study the cellular response to metal dysbiosis in MRSA, identifying new metal-dependent molecular vulnerabilities. Integrated transcriptomics, metabolomics and molecular analyses revealed that the antibacterial and oxacillin-resensitisation action of PZ is driven by dual metal stress: intracellular Zn accumulation and manganese (Mn) depletion. PZ disrupted central carbon metabolism at multiple key nodes, impairing glycolysis, the TCA cycle and respiration, leading to NADH and ATP depletion and compromised peptidoglycan biosynthesis. PZ also altered the metal-dependent oxidative stress response, resulting in superoxide accumulation. Collectively, this work presents the dynamic interplay between bacterial metal ion homeostasis, central metabolism, and β-lactam resistance. Uncovering how PBT2 subverts the adaptive responses of MRSA to host-imposed stresses contributes to our understanding of host-pathogen interactions and offers a foundation for developing novel antimicrobials based on metal homeostasis disruption.