Coaggregation between Actinomyces viscousus with streptococcus pyogenes and Streptococcus agalactiae

Interbacterial coaggregation between Actinomyces viscosus indigenous to the human mouth and Stre ptococcus pyogenes and Streptococcus agalactiae was studied. Fifteen of twenty-six strains of Streptococcus pyogenes and thirteen of thirty-one Streptococcus agalactiae showed a coaggregation with Actinomyces viscosus strain. The results show that the coaggregation mechanism required calcium and was dependent on pH. Some coaggregations were inhibited by 0.06 M. lactose and by 1 M. NaCl.