Characteristics of multimodal co-aggregation between Fusobacterium nucleatum and streptococci

The co-aggregation characteristics between Fusobacterium nucleatum and streptococci were examined to clarify the adherence factors participating in the co-aggregation. Nineteen strains of F. nucleatum were classified into 8 groups according to co-aggregation titer and inhibition by L-arginine, L-lysine and N-acetyl-D-galactosamine (or lactose). The inhibition activity was, however, very different from strain to strain. With two fusobacterial strains, two inhibitors, which were both inhibition negative on their own, completely inhibited the co-aggregation when used together in a mixture. In some co-aggregation pairs, the protease treatment of F. nucleatum inactivated one of the adherence factors, and resulted in the change of inhibition characteristics. These results indicate the multimodal co-aggregation of F. nucleatum with streptococci mediated by L-arginine-sensitive, L-lysine-sensitive, N-acetyl-D-galactosamine-sensitive and in some resistant factors, and that the adherence factor or factors participating the co-aggregation change according to the co-aggregation partners.