Chemoprophylaxis of infective endocarditis

Infective endocarditis is a serious disease with a continuing mortality of approximately 20%. Risk factors include a variety of congenital and acquired heart diseases. Infection follows an episode of bacteraemia which is most commonly due to oral bacteria, notably streptococci. Less commonly bacteraemia may arise from surgical procedures or diseases of the gastrointestinal and genitourinary tracts or from sepsis at other body sites, including intravenous drug abuse. Several societies and associations have published recommendations for the prevention of bacteraemia in those at risk from endocarditis through the use of perioperative antibiotic chemoprophylaxis. The recommendations are targetted at patients with defined cardiovascular lesions undergoing dental and other procedures known to predictably produce bacteraemia. The major recommendations for standard risk patients undergoing dental procedures without general anaesthesia is high-dose oral penicillin or amoxycillin. Alternative agents include erythromycin and clindamycin. For those requiring general anaesthesia, parenteral regimens are generally recommended although the British Society for Antimicrobial Chemotherapy permits an oral amoxycillin regimen 4 hours preoperatively. For specified gastrointestinal and genitourinary procedures a 2-drug regimen of ampicillin/amoxycillin (or vancomycin for penicillin-allergic patients) plus an aminoglycoside is generally recommended. The emphasis has been to simplify the earlier regimens without compromising the antimicrobial protection with a view to encouraging maximum compliance. The latter continues to be a problem where drug recommendations are either complex or include multiple drug or dosage recommendations. The emphasis on maintaining good dental health is endorsed by all authorities.