Molecular Epidemiology and Virulence Factors of Methicillin-Resistant Staphylococcus Aureus Strains in a Romanian University Hospital Epidemiologia Molecular Ă I Factori De Virulen Ńă Ai Tulpinilor De Staphylococcus Aureus Meticilino-Rezistente Izolate Dintr-Un Spital Clin Ic Din România