Serological and Biological Characteristics and Penicillin Resistance of Non-hemolytic Streptococci Isolated from Subacute Bacterial Endocarditis

Abstract

34 strains of nonhemolytic streptococci isolated from 32 cases of subacute bacterial endocarditis were studied for serol. and biol. characteristics and for in vitro penicillin resistance. They were divided into 4 groups, Streptococcus s.b.e., S. salivarius, Enterococcus and unclassified. The report of the existence of a new var. of nonhemolytic streptococcus, based on serol. and biol. characteristics and designated as Streptococcus s.b.e., was confirmed. The resistance of the Streptococcus s.b.e. group to penicillin was found to be slightly > the unclassified streptococci, but none of the former strains was markedly resistant to the antibiotic in vitro. The enterococci were found to be markedly resistant to penicillin. Of the 34 strains isolated, 9 were Streptococcus s.b.e., 2 each 5. salivarius and Enterococcus, and 21 were unclassified streptococci.