Association between biomass formation and the prognosis of infective endocarditis due to Staphylococcus aureus Nuria Fernández-Hidalgo; Jana Basas; Ester Viedma; Aida Ribera; Nieves Larrosa; Dafne Pérez-Montarelo; Fernando Chaves; Joan Gavaldà; Benito Almirante;