Interference with Aggregatibacter actinomycetemcomitans: colonization of epithelial cells under hydrodynamic conditions.

Introduction: Microbial interactions are considered to be important for bacterial colonization. Interactions that inhibit colonization of pathogens could possibly be used as a new treatment approach for periodontitis. The aim of this study was to test this hypothesis on soft surfaces in vitro, taking into account the hydrodynamic forces continuously present in vivo.
Methods: Cultured epithelial cells were precolonized with Streptococcus sanguinis KTH-4, Streptococcus cristatus CC5A, Streptococcus salivarius TOVE and Streptococcus mitis BMS before Aggregatibacter actinomycetemcomitans colonization. Experiments were performed in a modified Robbins-device-type flow cell. Bacterial colonization and the number of epithelial cells were evaluated by microbial culturing and quantitative polymerase chain reaction.
Results: The streptococci were able to inhibit A. actinomycetemcomitans colonization on soft tissue surfaces under flow conditions. Statistically significant differences were found between streptococcal pretreatments and the controls, with the most pronounced effect caused by S. sanguinis.
Conclusion: These data confirm the possibility of applying beneficial bacteria in periodontal treatment.