Project Summary Alcohol associated health problems are a major medical burden in industrialized countries. Alcoholic hepatitis (AH) is a distinct acute on chronic disease with significant morbidity and mortality. Patients with alcoholic hepatitis show intestinal dysbiosis and increased intestinal permeability. Recent evidence suggests that AH is a gut dysbiosis driven disease. The mechanism of how the microbiota contributes to AH is largely unknown. Results from our laboratories suggest that alterations in the bacterial microbiome contribute to the development of alcoholic liver disease. We observed significantly greater numbers of Enterococcus faecalis in fecal samples from AH patients, which exacerbates alcoholic liver disease in preclinical models. Although the intestinal microbiome consists of bacteria, fungi, bacteriophages and viruses, research in the field of alcoholic liver disease has almost exclusively focused on the interaction between the host and bacteria. We demonstrate alcohol-associated compositional changes in gut fungal populations with reduced fungal diversity and overgrowth of Candida albicans in AH patients. The degree of exposure to fungal products such as β-glucan correlates with mortality in patients with cirrhosis due to alcohol abuse. We have generated a testable central hypothesis of this proposed collaborative research application that implicates disturbances in intestinal bacteria, bacteriophages and fungi as important etiological factors for the development of AH. We predict that the degree of dysbiosis and translocated microbial products correlate with levels of systemic and hepatic inflammation, and with AH severity. Through the proposed study we will characterize gut bacteriophages and bacteria in patients with AH. Towards this goal, we will use lytic bacteriophages to reduce intestinal Enterococcus faecalis and improve liver disease in a humanized AH model (Aim 1). We will characterize the intestinal mycobiome in patients with AH. Reducing intestinal fungal overgrowth with antifungals or supplementation with probiotic Saccharomyces boulardii will ameliorate liver disease in a humanized AH model (Aim 2). We believe these studies will provide important insights into the contribution of the intestinal microbiome to AH. Eventually this approach will lead to new therapeutics for patients with alcoholic hepatitis.