The literature on the treatment of endocarditis lenta recommends massive antibiotic therapy. Experience has proved that this is inevitable. However, the clinician has found it difficult to understand why the treatment of endocarditis lenta in particular calls for considerably higher penicillin doses than other diseases to destroy the microorganisms found sensitive to penicillin in vitro.
According to Moore (1946) the center of the vegetation is necrotic and relatively poor in cells; it is surrounded by bacterial colonies covered by fibrin and platelet masses. Studying the penetration of the fibrin clot by penicillin, Weinstein et al. (1951) found that it took two hours for the penicillin concentration inside the clot to equal that in the fluid outside. In addition, it was found that a viridans Streptococcus is capable of living in the fibrin clot in a penicillin concentration in which in other in vitro conditions it is easily destroyed. Hence it
KAIPAINEN WJ, SEPPALA K. Chemotherapy in Endocarditis LentaTwo-Year Follow-Up Study of One Hundred Two Cases. AMA Arch Intern Med. 1957;100(3):419–422. doi:10.1001/archinte.1957.00260090075009