A method of altering intercellular interactions between a combination of microorganisms includes contacting a combination of different species of microorganisms with at least one mucin. Isolated compositions include a combination of microorganisms and at least one mucin. One microorganism of the combination inhibits cell growth or promotes cell death of at least one other microorganism of a different species in the combination. The combination of microorganisms with the mucin results an increase in cell growth or a reduction in cell death, respectively, of the at least one other microorganism.
