Fig. 7.

Interkingdom assemblages in human saliva behave like supraorganisms with new functionalities and disease-promoting activity. 1) C. albicans and S. mutans coassemble into structured cell groups in human saliva, which are remarkably similar to the native interkingdom aggregates found in intact saliva from diseased patients. 2) Bacteria and fungi collectively colonize the surface as a structured cell group with enhanced binding affinity. 3) The assemblage displays enhanced tolerance to shear stress and antimicrobials. 4) The assemblages behave as single units that grow faster than single-species aggregates, spreading three-dimensionally and merging with each other, resulting in high surface coverage. 5) The interkingdom assemblages display a novel mode of migratory group-level mobility with forward motions and a hitchhiking growth mechanism during biofilm initiation that allows nonmotile bacteria to relocate after surface colonization, which promotes biofilm spatial surface spreading. 6) The interkingdom assemblages cause extensive and severe damage of the tooth-enamel surface.