The isolation and characterization of milleri group streptococci from dental periapical abscesses.

Reports of the isolation of streptococci from dental abscesses have shown an association of the "S. milleri" group with such lesions. There has been considerable confusion regarding the taxonomy of these organisms, but the milleri group has recently been reclassified into three distinct species: Streptococcus anginosus, Streptococcus constellatus, and Streptococcus intermedius. In this study, 45 samples from dental periapical abscesses were examined. Milleri group streptococci were isolated from 16 patients (37%), 15 being identified as S. anginosus and one as S. intermedius. In one patient, S. anginosus was isolated in pure culture, and it would appear that this is the predominant species of milleri group streptococci associated with periapical abscesses.