A method of treating or preventing endocarditis in a human patient in need of therapy is disclosed. The method comprises identifying a patient inflicted with or being at risk of contracting Staphylococcus aureus, Enterococcus faecalis, or Enterococcus faecium; and locally delivering to or in the vicinity of a heart valve a therapeutically or prophylactically effective amount of rifampicin, daptomycin, dalbavancin, vancomycin, or gentamycin, or a combination of rifampicin, daptomycin, dalbavancin, vancomycin, and gentamycin. The method comprises treatment or prevention of a bacterial biofilms on the endocardium caused by Staphylococcus aureus, Enterococcus faecalis, or Enterococcus faecium.