Chondroitin sulfate-depolymerizing activity in Streptococcus intermedius and other streptococci

The type strain (ATCC 27335) and 18 human oral isolates of Streptococcus intermedius and some other related streptococcal species were tested for chondroitin sulfate C-depolymerizing activity employing a modified screening plate method of Smith and Willett. As the results, S. intermedius strains except for ATCC 31412 strain were found to possess this activity. Propionibacterium acnes ATCC 11828 used as a positive control strain demonstrated strong activity, whereas S. intermedius strains showed only slightly detectable activity. This finding might be interesting in view of the classification of this species as well as its pathogenicity.