Speaker
Description
The mammalian intestine is a unique ecosystem for thousands of bacterial species and strains. How naturally co-existing bacteria of the microbiota interact with each other is not yet fully understood. Here, we systematically studied over 100 interactions between bacteria of the genus Bacteroides that were isolated from the intestine of healthy mice. We find a vast diversity of interactions ranging from positive to negative. Intraspecific interactions are dominated by mutualistic and parasitic interactions. Interspecific interactions are subject to intraspecific diversity and differ between hosts. These findings on obligate host-associated bacteria (i) identify novel molecular mechanisms by which bacteria affect each other and (ii) demonstrate high strain-level variation of bacteria-bacteria interactions. The results have implications for our basic understanding of the microbiota and for the design of synthetic microbial communities.