Antimicrobial Treatment of Infective Endocarditis due to Viridans Streptococci, Enterococci, and Staphylococci

INFECTIVE endocarditis is a microbial infection of the endocardial surface of the heart. It most frequently involves the heart valves (native or prosthetic) but can occur on the mural endocardium or intravascular foreign bodies such as intracardiac patches and surgically constructed shunts used to repair congenital heart defects. A similar clinical illness, infective endarteritis, develops when there is infection of arteries, including arteriovenous shunts, patent ductus arteriosus, the great vessels, or aneurysms. Depending primarily on the virulence of the infecting microorganism, the clinical course of infective endocarditis may be prolonged and indolent or abrupt and fulminant. Clinical manifestations of infective endocarditis are variable but frequently include fever, cardiac murmurs, cardiac dysfunction, splenomegaly, petechiae, systemic emboli, anemia, and hematuria. Before the era of antibiotics, the disease was uniformly fatal. Organisms that commonly cause infective endocarditis are gram-positive cocci: viridans streptococci, enterococci,Streptococcus bovis, and staphylococci. Together, these organisms account for the