INDUCTION OF DENTAL CARIES IN GNOTOBIOTIC RATS WITH A LEVAN-FORMING STREPTOCOCCUS AND A STREPTOCOCCUS ISOLATED FROM SUBACUTE BACTERIAL ENDOCARDITIS

A levan-forming streptococcus (strain SS2) isolated from the human oral cavity, and a dextran-forming streptococcus isolated from the blood of a patient with subacute bacterial endocarditis (strain SBEL) have been found to induce dental caries in pure culture in gnotobiotic rats. Strain SS 2 formed minor plaque deposits and induced fissure caries in rats fed diet 585. However, this organism formed masses of plaque, and induced primarily root caries and alveolar bone loss in rats maintained on diet 2000. Strain SBEL produced carious lesions in fissures and on smooth surfaces of rats fed diet 585, and induced alveolar bone loss. Dextran-forming streptococci were found to be present, but in low proportions, in normal human faeces. Only one of nine strains of human cariogenic streptococci tested was found to react with fluorescein labelled antisera to streptococcus types AHT and BHT. © 1968.