Identification and classification of species within the Streptococcus sanguis group

A biochemical identification scheme has been produced that allows for the differentiation of nine distinct species within the Streptococcus sanguis group. The species are S. sanguis, S. gordonii, S. crista, S. oralis, S. parasanguis, S. defectivus, S. adjacens and S. mitis, which have been previously described, and a new species, S. australis; in addition two distinct subspecies, S. oralis subsp. corona and S. oralis subsp. mitior, have been identified. DNA-DNA hybridization confirmed the separation of strains into the species. A new type of peptidoglycan peptide linkage, lys-ala-gly was also found within the species S. parasanguis and S. australis that has not been observed within the streptococci previously. DNA fingerprinting was shown to be a useful method for discriminating between strains within species, but did not allow discrimination between species.