Vancomycin-resistant Staphylococcus aureus (VRSA) represents strains of S. aureus that have ability of resistance to the glycopeptide antibiotic vancomycin. S. aureus is the most common cause of nosocomial infections. The glycopeptides-notably vancomycin-have traditionally been the mainstay of treatment of methicillin-resistant S. aureus (MRSA) but overuse has led to the emergence of vancomycin-intermediate and vancomycin-resistant S. aureus (VISA and VRSA, respectively). Limited treatment options make resistant S. aureus infections particularly difficult and costly to treat, especially in areas of poor antibiotic penetration, such as joint spaces and the central nervous system. A gene known as vanA is a major determinant, which is transferable and can be acquired by sensitive bacteria from resistant organisms.
