Unmasking MRSA's Armor: Molecular Mechanisms of Resistance and Pioneering Therapeutic Countermeasures

Methicillin-resistant Staphylococcus aureus (MRSA), characterized by high-level β-lactam resistance and increasing multi-drug resistance, poses a severe and growing global threat to human health and public safety. This review examines MRSA's complex resistance mechanisms, including mecA/mecC-mediated expression of low-affinity PBP2a, regulatory roles of auxiliary genes like fem and vanA, enzymatic inactivation by β-lactamases and modifying enzymes, efflux pump activity, and biofilm formation. We also systematically review novel therapeutic strategies, such as combination therapies, phage-derived biofilm disruptors, membrane-targeting silver nanoparticles, cell-penetrating antimicrobial peptides, colonization-competitive probiotics, and antibiotic-synergizing phytochemicals. These advances provide critical insights for developing effective countermeasures against MRSA, while highlighting the urgent need for global collaboration, antibiotic stewardship, and innovative drug development to combat antimicrobial resistance.