Why can certain medical and dental procedures lead to bacterial endocarditis?
Different kinds of bacteria normally are found in all people’s mouths, rectal areas, and in the tube through which they urinate (“urethra”). Normally only a small number of these bacteria get through the tissue barriers in those areas and enter the blood stream, usually only for a short period of time. In these situations, the body’s own defense system destroys the bacteria before they can do any harm to the body. However, when certain medical or dental procedures are performed in these areas, especially those associated with bleeding, the numbers of bacteria and the length of time that the bacteria are getting into the blood stream can increase. This is because of the expected injury to the tissues that normally form a barrier to the bacteria. These events increase the chance that the bacteria will have the opportunity to infect an abnormal heart valve. Antibiotics given just before these types of medical or dental procedures can help the body’s own defense system destroy the bacteria
