26.07.2023The Kümmerli group shows that negative interactions and virulence differences drive polymicrobial infection dynamics

See Schmitz et al., Proc Biol Sci. 

Bacterial infections are often polymicrobial, leading to intricate pathogen-pathogen and pathogen-host interactions. Here, the Kümmerli group co-infected larvae of Galleria mellonella with one to four opportunistic human pathogens to show that host mortality is always determined by the most virulent bacterial species, regardless of the number of species and pathogen combinations injected. This work reveals positive associations between a pathogen's growth inside the host, its competitiveness towards other pathogens and its virulence, supporting the experimentally validated prediction that treatments against polymicrobial infections should first target the most virulent species to reduce host morbidity.