This episode features Prof. Kevin Foster PhD from University of Oxford (UK), speaking about his lab’s ecological approach to the gut microbiome and efforts to understand and predict dynamics of different species in the microbiome. They also focus on how these ecological dynamics map onto health outcomes, and how they inform interventions. In a 2023 paper, they explored the concept of colonization resistance in the gut, and why certain bacteria or combinations of bacteria are particularly good at preventing pathogens from thriving. Both diversity and composition are important for determining the extent to which a community resists a pathogen. But a microbiome may equally resist a probiotic that’s introduced because the probiotic microorganism doesn’t have access to a unique nutrient. How bacteria interact with each other can help determine resiliency or stability of the microbiome overall. While it’s true that hundreds of species of bacteria exist in the gut, the scale at which the microbes interact locally is much more limited (on the scale of tens of species). Episode abbreviations and links: 2023 paper examining colonization resistance against 2 pathogens: Microbiome diversity protects against pathogens by nutrient blocking.  About Prof. Kevin Foster PhD: Professor Kevin Foster FRS is the Chair of Microbiology at the Dunn School of Pathology, University of Oxford. Prior to this, he was Professor of Evolutionary Biology in the departments of Biology and Biochemistry at Oxford. Before Oxford, he had a lab at Harvard as a Bauer Fellow in the FAS Center for Systems Biology. He did his undergrad at Cambridge in Natural Sciences and his Ph.D. at the University of Sheffield in evolutionary biology. Professor Foster’s research integrates the traditional fields of ecology and evolution with the latest methods in computation, microbiology, molecular genetics, and the study of the mammalian microbiome. The lab focuses on how bacteria compete and succeed in their communities and seeks to use this to manipulate gut communities for better health.