The Treatment and Prophylaxis of Subacute Bacterial Endocarditis
SUBACUTE BACTERIAL ENDOCARDITIS is one of the important bacterial diseases which has been transformed from a uniformly fatal disease to one with a favorable outlook for cure since the era of antibiotic therapy. It is, however, an exceptional and perhaps unique disease in relation to the task that chemotherapy has to perform. Although the prevention of further bacterial growth by antibiotics and the subsequent disposal of surviving organisms by the natural defenses of the body are sufficient to eradicate most bacterial infections, they apparently are not sufficient in subacute bacterial endocarditis. The clinical course of the disease prior to the antibiotic era showed that host factors are incapable of eliminating this type of infection. To prevent relapse, chemotherapy must eliminate the last surviving organisms from the endocardial focus.
Consideration of the pathology in this disease helps us to understand the obstacles that antibiotics must surmount in order to eradicate this infection. The organisms are buried in fibrin and in scarred, avascular, necrotic tissue. To effect a cure, an agent with fibrin-penetrating and bacteria-killing properties must be present in high concentrations over an adequate period of time. It is, therefore, not surprising that bactericidal drugs are indicated in this disease rather than those that are bacteriostatic in their action. Both clinical and laboratory evidence1 indicate that the presence of bactericidal action is a prerequisite for the cure of subacute bacterial endocarditis.
In the treatment of this condition the failure of sulfonamides was early evidence that bacteriostasis in addition to host factors. . .