Bacteriology of the Blood and Joints in Rheumatic Fever

1. During the Spring of 1928, 29 patients with acute rheumatic fever were subjected to blood cultures, of whom 9, or 31 per cent, yielded a streptococcus. During the Spring of 1929, 31 patients with acute rheumatic fever were studied by blood cultures, of whom 26, or 83.9 per cent, yielded a streptococcus. The higher percentage of positive cultures in the 1929 series appears to have been due to improved cultural methods. 2. Of the 35 strains of streptococci recovered from blood cultures, 33 have been classified as alpha streptococci (Str. viridans); one as a beta streptococcus (Str. hemolyticus); and one a gamma streptococcus (Str. anhemolyticus). Some of the viridans strains produced very little green on blood media. 3. Agglutination and absorption tests indicate that the strains of streptococcus viridans recovered from the blood of patients with rheumatic fever show a tendency to fall into specific biological groups. 4. In 7 patients with rheumatic fever who were subjected to cultures from affected joints, 5, or 71.4 per cent, yielded a streptococcus viridans. In 3 patients in whom green streptococci were recovered from both the blood and joint, agglutination and absorption tests proved the identity of the strains isolated from the two sources. 5. These findings corroborate those of previous investigators and make it difficult to escape the conclusion that rheumatic fever is a streptococcal infection usually of the alpha or viridans type. 6. The pathogenesis of rheumatic fever in respect to the joint lesions appears to be analogous to that of infectious arthritis and gonococcal arthritis. Bacterial allergy probably influences the clinical picture in all three conditions, but in each instance the joint manifestations are primarily dependent upon localization of bacteria in the joint, with subsequent infection.