title: Different food sources elicit fast changes to bacterial virulence.
abstract: Environmentally transmitted, opportunistic bacterial pathogens have a life cycle that alternates between hosts and environmental reservoirs. Resources are often scarce and fluctuating in the outside-host environment, whereas overcoming the host immune system could allow pathogens to establish a new, resource abundant and stable niche within the host. We tested if short-term exposure to different outside-host resource types and concentrations affect Serratia marcescens-(bacterium)'s virulence in Galleria mellonella (moth). As expected, virulence was mostly dictated by the bacterial dose, but we also found a clear increase in virulence when the bacterium had inhabited a low (versus high) resource concentration, or animal-based (versus plant-based) resources for 48 h prior to injection. The results suggest that temporal changes in pathogen's resource environment can induce very rapid changes in virulence and affect infection severity. Such changes could also play an important role in shifts from environmental lifestyle to pathogenicity or switches in host range and have implications for the management of opportunistic pathogens and disease outbreaks.
authors.affiliation: Centre of Excellence in Biological Interactions, Department of Biological and Environmental Science, University of Jyväskylä, PO Box 35, Jyväskylä 40014, Finland tketola@jyu.fi.
authors.forename: T
authors.initials: T
authors.lastname: Ketola
authors.affiliation: Centre of Excellence in Biological Interactions, Department of Biological and Environmental Science, University of Jyväskylä, PO Box 35, Jyväskylä 40014, Finland.
authors.forename: L
authors.initials: L
authors.lastname: Mikonranta
authors.affiliation: Centre of Excellence in Biological Interactions, Department of Biological and Environmental Science, University of Jyväskylä, PO Box 35, Jyväskylä 40014, Finland Centre of Excellence in Biological Interactions, Department of Biological and Environmental Science, University of Helsinki, PO Box 65, Helsinki 00014, Finland.
authors.forename: J
authors.initials: J
authors.lastname: Laakso
authors.affiliation: Centre of Excellence in Biological Interactions, Department of Biological and Environmental Science, University of Jyväskylä, PO Box 35, Jyväskylä 40014, Finland.
authors.forename: J
authors.initials: J
authors.lastname: Mappes
mesh_terms: D000220:Adaptation, Biological; D000818:Animals; D058491:Bacterial Load; D004777:Environment; D054884:Host-Pathogen Interactions; D007814:Larva / Q000382:microbiology; D008018:Life Cycle Stages; D009036:Moths / Q000382:microbiology*; D012706:Serratia marcescens / Q000378:metabolism / Q000472:pathogenicity*; D014774:Virulence
keywords: Serratia marcescens; eutrophication; pathogen; plasticity; resources; virulence