TI 07.003_068

Understanding the role of diet in the context of microbiome – immune interactions in hospitalized infectious disease patients

01/10/2024 to 30/09/2025

In addition to antibiotics,increasing evidence is accumulating that also non-antibiotic drugs may impact on individual gutcommensals and even on total intestinal ecologies affecting its metabolic function and colonizationresistance. Dietary shifts, including the introduction of high-fat, low-fiber diets, which
areincreasingly consumed worldwide, also exert a significant impact on microbiome composition and itsmetabolome. As such, low-fiber diets and even caloric restriction can lead to reduced colonizationresistance against Clostridioides difficile infection, for instance. On the other hand, highfibercontent in diets has been shown to mitigate the loss of antibiotic-induced microbiome diversity andmetabolic output. First evidence suggests that nutrition can also increase the antibacterial efficacyof antibiotics through gut microbiome metabolites.
In previous work of my co-supervisor Prof. Stein-Thoeringer, he has described that antibiotic exposuresand dietary factors facilitate microbiome dysbiosis with pathobiont expansion in immunocompromisedpatients. In an international cohort of patients undergoing allogenic hematopoietic cell transplantation(allo-HCT) the gut microbiome was observed to be dominated by Enterococcus spp., which wasassociated with increased mortality. Apart from broad-spectrum antibiotic treatments, the dietarydisaccharide lactose was identified to facilitate the growth and expansion of enterococci in preclinicalmodels, and depletion of lactose from diet reduced the enterococcal load and allo-HCT-relatedmortality in mice. In two other studies in humans and mouse models, they found significantmicrobiome – diet interactions for various dietary sugars in host metabolism or gastrointestinaldisorders. However, they have not yet carried out systematic analyses of diet – drug interactionson the gut microbiome in any of these studies.