歯科治療と感染性心内膜炎の予防

Infective endocarditis is a serious infection of the endothelial surfaces of the heart, especially at the valves. Oral commensal bacteria are the most common etiologic agents of this disease. Infective endocarditis can be established when all the 3 conditions are present simultaneously, i.e., (1) the introduction of bacteria into the bloodstream, (2) predisposing impairments in the heart, and (3) the virulence of bacteria. Common dental procedures, even non-surgical dental procedures, can often cause bacteremia of oral commensals. Periodontally diseased patients are at risk from bacteremia even after brushing the teeth or eating meals. Bacteremia itself rarely affect healthy people but they can result in mortal infective endocarditis in those who have a predisposed risk for this disease, such as those with heart valve diseases, pacemaker implantation, etc. Despite advances in diagnosis, antimicrobial therapies, surgical techniques and management of complications, patients with infective endocarditis still have substantial mortality. To prevent this infection, antibiotics is currently used, however, their frequent uses generates drug-resistant mutant bacteria, which is a serious social problem. Therefore, development of novel alternative drugs to be used instead of the current antibiotics is highly desired. We are now using several types of combinatorial peptide libraries to search for small size molecular mimetics that can interfere with the adhesion of bacteria to the target tissue. The use of such peptides is expected to lead to the development of compounds for a novel preventive drug which does not kill bacteria, thus making it safer and less likely to generate drugresistant mutants.