Set of Bacteroides thetaiotaomicron strains expressing single capsular polysaccharides

Many gut commensal microorganisms produce capsular polysaccharides (CPS). While CPS have been well studied in pathogenic microbes, it is yet unclear what roles these structures play in commensal microbes. Members of the gut-dwelling Bacteroides genus typically encode for multiple CPS synthesis loci. To facilitate identification of the functions of individual Bacteroides CPS, we generated a set of isogenic strains of the type strain of Bacteroides thetaiotaomicron that each encode and express a single CPS synthesis locus and compared these to each other and to the wild-type strain (which can express 8 different CPS loci). We validated these new strains by genome sequencing and expression analyses.