Project Summary GI colonization with C. albicans is common for humans and generally does not have adverse effects on human health. However, if a patient becomes immunocompromised, colonizing C. albicans cells can escape the GI tract, reach the blood stream and cause disseminated, life-threatening disease. GI colonization is therefore significant because disease-causing fungal cells arise from the populations that colonize the host as harmless commensals. The goal of this research project is to develop a dietary intervention that reduces GI colonization with Candida. The project is based on preliminary results that demonstrate the ability of diets high in medium chain triglycerides to reduce GI colonization by C. albicans in mice. The long-term goal of this project is to reduce the incidence of candidemia and candidiasis by reducing the level of colonizing Candida in patients who are at high risk. In Specific Aim 1, the goal is to test the hypothesis that a modified diet will reduce the level of Candida gut colonization in preterm infants, a population that is at risk for developing systemic Candida infection. The focus of Specific Aim 2 is to identify changes that occur in microbiota composition as a consequence of dietary change and to determine whether the colonizing Candida strains change during the administration of the modified diet. These studies may lead to the development of a dietary method for decreasing Candida gut colonization. The diet may reduce the incidence of invasive candidiasis in hospitalized patients across the life cycle who are at high risk for disease.