BIOTHERAPEUTIC EFFECTS OF PROBIOTIC BACTERIA ON CANDIDIASIS IN IMMUNODEFICIENT MICE

Four species of probiotic bacteria were assessed for their capacities to protect athymic bg/bg-nu/nu and euthymic bg/bg-nu/+ mice from mucos al and systemic candidiasis. Each bacterial species and Candida albica ns colonized the gastrointestinal tracts of both strains of mice. The presence of probiotic bacteria (Lactobacillus acidophilus, Lactobacill us reuteri, Lactobacillus casei GG, or Bifidobacterium animalis) in th e gastrointestinal tracts prolonged the survival of adult and neonatal bg/bg-nu/nu mice compared to that of isogenic mice colonized with C. albicans alone, The incidence of systemic candidiasis in bg/bg-nu/nu m ice was significantly reduced by each of the four probiotic bacterial species, The numbers of C. albicans present in the alimentary tracts o f euthymic bg/bg-nu/+ mice were significantly reduced by L. casei GG a nd B. animalis. None of the probiotic bacteria species completely prev ented mucosal candidiasis, but B. animalis reduced its incidence and s everity. Probiotic bacteria also modulated antibody-and cell-mediated immune responses to C. albicans. The prolonged survival of mice, decre ased severity of mucosal and systemic candidiasis, modulation of immun e responses, decreased number of C. albicans in the alimentary tract, and reduced numbers of orogastric infections demonstrated not only tha t probiotic bacteria have biotherapeutic potential for prophylaxis aga inst and therapy of this fungal disease but also that probiotic bacter ia protect mice from candidiasis by a variety of immunologic (thymic a nd extrathymic) and nonimmunologic mechanisms in this model.