Effect of Streptococcus sanguinis/Porphyromonas gingivalis single and combined biofilms upon platelet aggregation

Oral Diseases (2012) 18, 586594 Objective: To assess the effect of two oral bacteria Streptococcus sanguinis and Porphyromonas gingivalis upon platelet aggregation. Materials and Methods: Streptococcus sanguinis, P.gingivalis, S.sanguniis + P.gingivalis were added to platelet-rich plasma and platelet aggregation measured using a platelet aggregometer. Platelets were passed through a flow chamber with S.similar to sanguinis, P.gingivalis or a biofilm of S.sanguinis and P.gingivalis coated with saliva. Platelet adhesion to the chamber was observed under a fluorescence microscope for 15 min. The positive control was platelets treated with adrenaline; the negative control was platelets treated with phosphate-buffered saline. Results: The mean (+/- s.e.) aggregation magnitude of S.sanguinis and P.gingivalis was 77.7 +/- 7.4% and 79.3 +/- 9.9%, respectively. The aggregation magnitude of S.sanguinis + P.gingivalis was 51.3 +/- 12.9%, which was significantly lower than that for S.sanguinis/P.gingivalis (P < 0.05). In the flow chamber system, platelets adhered to S. sanguinis/P.gingivalis respectively within 3 min, and reached a plateau at 515 min. Under the condition of the S.sanguinis- and P.gingivalis-saliva biofilm, platelet adhesion to the biofilm was significantly reduced at 515 min (P < 0.05). Conclusions: In the static or dynamic flow system, platelets adhered to S.sanguinis or P.similar to gingivalis. However, if S.sanguinis was mixed with P.gingivalis, the aggregation magnitude (%) was significantly reduced.