title: Metabolite cross-feeding enhances virulence in a model polymicrobial infection.
abstract: Microbes within polymicrobial infections often display synergistic interactions resulting in enhanced pathogenesis; however, the molecular mechanisms governing these interactions are not well understood. Development of model systems that allow detailed mechanistic studies of polymicrobial synergy is a critical step towards a comprehensive understanding of these infections in vivo. In this study, we used a model polymicrobial infection including the opportunistic pathogen Aggregatibacter actinomycetemcomitans and the commensal Streptococcus gordonii to examine the importance of metabolite cross-feeding for establishing co-culture infections. Our results reveal that co-culture with S. gordonii enhances the pathogenesis of A. actinomycetemcomitans in a murine abscess model of infection. Interestingly, the ability of A. actinomycetemcomitans to utilize L-lactate as an energy source is essential for these co-culture benefits. Surprisingly, inactivation of L-lactate catabolism had no impact on mono-culture growth in vitro and in vivo suggesting that A. actinomycetemcomitans L-lactate catabolism is only critical for establishing co-culture infections. These results demonstrate that metabolite cross-feeding is critical for A. actinomycetemcomitans to persist in a polymicrobial infection with S. gordonii supporting the idea that the metabolic properties of commensal bacteria alter the course of pathogenesis in polymicrobial communities.
authors.affiliation: Section of Molecular Genetics and Microbiology, The University of Texas at Austin, Austin, Texas, United States of America.
authors.forename: Matthew M
authors.initials: MM
authors.lastname: Ramsey
authors.forename: Kendra P
authors.initials: KP
authors.lastname: Rumbaugh
authors.forename: Marvin
authors.initials: M
authors.lastname: Whiteley
mesh_terms: D000038:Abscess / Q000382:microbiology; D000818:Animals; D018920:Coculture Techniques; D060085:Coinfection / Q000382:microbiology*; D005947:Glucose / Q000378:metabolism; D019344:Lactic Acid / Q000378:metabolism*; D051379:Mice; D056265:Microbial Interactions; D009154:Mutation; D015661:Pasteurellaceae / Q000235:genetics / Q000254:growth & development / Q000472:pathogenicity*; D054773:Streptococcus gordonii / Q000235:genetics / Q000254:growth & development / Q000472:pathogenicity*
chemical_list: D019344:Lactic Acid; D005947:Glucose