Intrageneric coaggregation among strains of human oral bacteria: potential role in primary colonization of the tooth surface.

Of the 122 human oral bacterial strains tested from 11 genera, only streptococci and a few actinomyces exhibited coaggregation among the strains within their respective genera. Eight of the ten streptococci showed multiple intrageneric coaggregations, all of which were inhibited by galactosides. The widespread intrageneric coaggregation among the streptococci and the less extensive coaggregation among the actinomyces offers an explanation for their accretion on cleaned tooth surfaces and their dominance as primary colonizers.