Isolation, Identification and Prevalence of Streptococcus anginosus, S. intermedius and S. constellatus from the Human Mouth

This study was carried out to determine the prevalence and proportional distribution of the potentially pathogenic species Streptococcus anginosus, S. intermedius and S. constellatus at sites within the human mouth. The samples from 162 different subjects included supragingival plaque and saliva (18 subjects), subgingival samples (14 subjects) and mouthrinsings (130 subjects). All three species were recovered on nalidixic acid sulphamethazine selective agar at rates comparable with those obtained on a non-selective medium (Columbia blood agar). S. anginosus was the most frequently isolated of the three species, being found in 610 per cent of subjects examined, while S. intermedius and S. constellatus were recovered from 53 per cent and 13 per cent of subjects respectively. S. anginosus was recovered more frequently and in higher numbers at all oral sites examined than the other two species. S. constellatus was isolated least often and in lower numbers, except in the subgingival samples where it occurred a...