Understanding the Evolution of Methicillin-Resistant Staphylococcus aureus

Staphylococcus aureus is a gram-positive coccus that is among the most adaptable of pathogenic bacteria, particularly in developing resistance to antibiotics. The emergence of strains resistant to all current antibiotics is a real and growing concern. Understanding how S. aureus acquires drug resistance and spreads within health care institutions and communities is critical in developing containment strategies. Molecular typing strategies have become powerful tools in this regard, providing key insights regarding the evolution of S. aureus. This article reviews the current knowledge on the origins of methicillin resistance, the background of early resistant strains, and the changing landscape of drug-resistant S. aureus, particularly in the community setting.