most common cause of prosthetic valve endocarditis
The viridans group of streptococci is the most common cause of endocarditis involving native heart valves in patients with congenital heart disease and in patients who are not injection drug users.5 Coagulase-positive staphylococci (Staphylococcus aureus) commonly cause bacterial endocarditis in patients with prosthetic valves and in injection drug users.6 Presence of these organisms is also a common cause of acute bacterial endocarditis in persons whose heart valves were previously normal.7