Prophylactic Immunization against Streptococcus sanguis

Streptococcus sanguis (the Streptococcus s.b.e. of Loewe), originally identified by White and his coworkers, has, with few exceptions, been isolated only from the blood stream of patients with subacute bacterial endocarditis (White, 1944; White and Niven, 1946; Niven and White, 1946; Loewe et al., 1946; Niven et al., 1946; Washburn et al., 1946). This causative organism has a type specificity as established by the following biological and serologic criteria: (1) it produces greening of blood agar in 24 hours; (2) it hydrolyzes arginine in 48 hours; (3) it ferments inulin within 1 week; (4) it does not ferment raffinose within 1 week; (5) it fails to produce slime on 5 per cent sucrose gelatin agar in 24 hours; and (6) it displays a type-specific precipitin reaction in immune serum within 10 to 20 minutes. Loewe, Plummer, Niven, and Sherman (1946) and, later, Loewe and AltureWerber (1946) reported on the prognostic significance of Streptococcus sanguis in subacute bacterial endocarditis and stressed the serious implications of infection with this organism. It was responsible for most of the treatment failures in our series of more than 200 endocarditis patients who received antibiotic therapy at the Jewish Hospital of Brooklyn. It was pointed out in these communications that the orgailism was apparently refractory to the therapy despite the fact that in the test tube it had the same range of sensitivity to penicillin or streptomycin as had other members of the Streptococcus viridans group. Even in the successfully treated patients massive amounts of penicillin or streptomycin, or both, were required uninterruptedly over a span of 5 to 8 weeks in order to terminate the infection. Hehre and Neill (1946) described a dextran-producing streptococcus isolated from patients with subacute bacterial endocarditis. From their description it is highly probable that the organism is identical with Streptococcus sanguis. Schneierson (1948) recently confirmed the occurrence and type specificity of Streptococcus sanguis in a study of viridans strains isolated from patients with subacute bacterial endocarditis. The present report concerns observations on an unselected group of 56 out of a total of 152 recovered endocarditis patients who, within the past 7 months, have been inoculated with a polyvalent vaccine consisting of 5 strains of Streptococcus sanguis isolated from the blood stream of patients with active bacterial endocarditis. These organisms used for preparation of the vaccine, although quite sensitive to penicillin in vitro, proved to be characteristically refractory in vivo.