COAGGREGATION OF PREVOTELLA-INTERMEDIA WITH ORAL ACTINOMYCES SPECIES

Five strains of Prevotella intermedia were examined for their ability to coaggregate with various gram-positive and gram-negative species of oral bacteria. Two of the P. intermedia strains coaggregated with sel ected Actinomyces species, P. intermedia 27 with Actinomyces viscosus T14V and Actinomyces naeslundii ATCC 12104, PK606, PK984, and PK947, a nd P. intermedia 113 with Actinomyces odontolyticus WVU 1546 and Actin omyces israelii WVU 838. Exposure of both Prevotella strains but not t he Actinomyces strains to heat, trypsin, or proteinase K abolished mos t coaggregations. All pairs were disaggregated by the addition of sodi um dodecyl sulfate, but only those coaggregations involving P. interme dia 113 were reversed by the addition of 2.0 M urea. P. intermedia 27 was sensitive to periodate oxidation, whereas the partner strains were stable to this treatment. Most coaggregations occurred in the presenc e of saliva; however, reactions involving P. intermedia 27 were not as strong as those of buffer-suspended cells. Treatment of both P. inter media 113 coaggregations pairs with proteinase K and the results obtai ned from suspension of these pairs in saliva suggest that different su rface molecules of this P. intermedia strain may mediate each of these coaggregations. These data suggest that all of these coaggregations i nvolve either a protein or glycoprotein on the Prevotella strain, whic h may interact with carbohydrates or carbohydrate-containing molecules on the surface of the Actinomyces strain.