Cardiovascular infections: bacterial endocarditis of oral origin. Pathogenesis and prophylaxis

The diagnosis infective endocarditis describes infection of the endocardial surface of the heart and indicates the presence of micro-organisms in the lesion. In most cases, the heart valves are affected, but the disease can also occur on septal defects or on the mural endocardium. The disease has been classified as acute or subacute based on the progression of the untreated disease. The acute form has a fulminant course with high fever and leukocytosis with death in less than 6 weeks. It is most often associated with infections caused by Staphylococcus aureus, Streptococcus pneumoniae or Streptococcus pyogenes. The subacute (death within 6 weeks to 3 months) and chronic (death more than 3 months) forms are mostly described together. These forms usually occur in patients with prior valvular disease and are characterized by a slow, indolent course with low-grade fever, night sweats, and weight loss. This form is usually caused by the viridansstreptococci. The above mentioned classification does not include the nonbacterial forms of endocarditis and enterococci often give rise to a disease intermediate between acute and subacute endocarditis. It is preferable to have a classification based on the micro-organism responsible since this classification has implications for the course followed and the appropriate antimicrobial agent to use. The clinical manifestations of the disease are so varied that they may be encountered in most medical subspecialities. Successful management is also dependent on the close cooperation of medical and dental disciplines.