Abstract: In one aspect of the present invention, a method is provided for reducing or eliminating antibiotic resistance in bacteria, comprising exposing the bacteria to a composition comprising a yeast cell wall preparation in an amount effective for reducing or eliminating resistance of the bacteria to at least one antibiotic. In one embodiment, the method comprises exposing the bacteria to the yeast cell wall preparation in an amount effective for eliminating a plasmid conferring resistance to the antibiotic, or for preventing transfer of the plasmid between bacteria. In another aspect, a method is provided for reducing prevalence of antibiotic-resistant bacteria in an animal, comprising administering to the animal a composition comprising a yeast cell wall preparation in an amount effective for reducing or eliminating the presence of an antibiotic-resistant bacterial population in the animal.