title: Microbiota-liberated host sugars facilitate post-antibiotic expansion of enteric pathogens.
abstract: The human intestine, colonized by a dense community of resident microbes, is a frequent target of bacterial pathogens. Undisturbed, this intestinal microbiota provides protection from bacterial infections. Conversely, disruption of the microbiota with oral antibiotics often precedes the emergence of several enteric pathogens. How pathogens capitalize upon the failure of microbiota-afforded protection is largely unknown. Here we show that two antibiotic-associated pathogens, Salmonella enterica serovar Typhimurium (S. typhimurium) and Clostridium difficile, use a common strategy of catabolizing microbiota-liberated mucosal carbohydrates during their expansion within the gut. S. typhimurium accesses fucose and sialic acid within the lumen of the gut in a microbiota-dependent manner, and genetic ablation of the respective catabolic pathways reduces its competitiveness in vivo. Similarly, C. difficile expansion is aided by microbiota-induced elevation of sialic acid levels in vivo. Colonization of gnotobiotic mice with a sialidase-deficient mutant of Bacteroides thetaiotaomicron, a model gut symbiont, reduces free sialic acid levels resulting in C. difficile downregulating its sialic acid catabolic pathway and exhibiting impaired expansion. These effects are reversed by exogenous dietary administration of free sialic acid. Furthermore, antibiotic treatment of conventional mice induces a spike in free sialic acid and mutants of both Salmonella and C. difficile that are unable to catabolize sialic acid exhibit impaired expansion. These data show that antibiotic-induced disruption of the resident microbiota and subsequent alteration in mucosal carbohydrate availability are exploited by these two distantly related enteric pathogens in a similar manner. This insight suggests new therapeutic approaches for preventing diseases caused by antibiotic-associated pathogens.
authors.affiliation: Department of Microbiology and Immunology, Stanford University School of Medicine, Stanford, California 94305, USA.
authors.forename: Katharine M
authors.initials: KM
authors.lastname: Ng
authors.forename: Jessica A
authors.initials: JA
authors.lastname: Ferreyra
authors.forename: Steven K
authors.initials: SK
authors.lastname: Higginbottom
authors.forename: Jonathan B
authors.initials: JB
authors.lastname: Lynch
authors.forename: Purna C
authors.initials: PC
authors.lastname: Kashyap
authors.forename: Smita
authors.initials: S
authors.lastname: Gopinath
authors.forename: Natasha
authors.initials: N
authors.lastname: Naidu
authors.forename: Biswa
authors.initials: B
authors.lastname: Choudhury
authors.forename: Bart C
authors.initials: BC
authors.lastname: Weimer
authors.forename: Denise M
authors.initials: DM
authors.lastname: Monack
authors.forename: Justin L
authors.initials: JL
authors.lastname: Sonnenburg
mesh_terms: D000818:Animals; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D001439:Bacteroides / Q000502:physiology; D050260:Carbohydrate Metabolism / Q000187:drug effects*; D016360:Clostridioides difficile / Q000502:physiology*; D004761:Enterocolitis, Pseudomembranous / Q000382:microbiology*; D005260:Female; D005643:Fucose / Q000378:metabolism; D020869:Gene Expression Profiling; D015964:Gene Expression Regulation, Bacterial; D007413:Intestinal Mucosa / Q000378:metabolism / Q000382:microbiology*; D008297:Male; D054892:Metagenome / Q000187:drug effects / Q000502:physiology; D051379:Mice; D019158:N-Acetylneuraminic Acid / Q000378:metabolism; D009439:Neuraminidase / Q000235:genetics / Q000378:metabolism; D012480:Salmonella Infections / Q000382:microbiology*; D012486:Salmonella typhimurium / Q000502:physiology*; D013047:Specific Pathogen-Free Organisms
chemical_list: D000900:Anti-Bacterial Agents; D005643:Fucose; D009439:Neuraminidase; D019158:N-Acetylneuraminic Acid