New trends in antibiotic prophylaxis of infective endocarditis in patients undergoing surgery in the oral cavity.

Viridans-streptococci, which normally reside in the oral cavity, are still the most common pathogens in infective endocarditis. During surgical procedures in the oral cavity, pharynx and respiratory tract, microorganisms may disseminate into the blood and cause infective endocarditis in predisposed patients. It is, therefore generally considered that these patients should be protected during surgery by an effective and simple antibiotic regimen. During recent years new recommendations for prevention of endocarditis have been presented in several countries. Single high dose amoxycillin or 2-dose phenoxymethylpenicillin are used in normal risk patients while 2-dose erythromycin or single high dose clindamycin may be used in patients allergic to penicillins. Parental agents are usually recommended in high risk patients with prosthetic heart valves, however, some countries prefer to administer peroral prophylaxis. Topical prophylaxis in the oral cavity is not included in any national recommendation, but may decrease the magnitude, as well as the frequency, of postsurgical bacteremia. Commonly used antiseptics such as chlorhexidine are not selective enough and causes overgrowth of some viridans-streptococci. More selectively acting agents, such as topical vancomycin, appear to be more suitable.