Within-host competition causes pathogen molecular evolution and perpetual microbiota dysbiosis.

ABSTRACT: Pathogens newly invading a host must compete with resident microbiota. This within-host microbial warfare could lead to more severe disease outcomes or constrain the evolution of virulence. By passaging a widespread pathogen (Staphylococcus aureus) and a natural microbiota community across populations of nematode hosts, we show that the pathogen displaced microbiota and reduced species richness, but maintained its virulence across generations. Conversely, pathogen populations and microbiota passaged in isolation caused more host harm relative to their respective no-host controls. For the evolved pathogens, this increase in virulence was partly mediated by enhanced biofilm formation and expression of the global virulence regulator agr. Whole genome sequencing revealed shifts in the mode of

SUBMITTER: Stevens EJ 

PROVIDER: S-EPMC12066030 | biostudies-literature | 2025 Jan

REPOSITORIES: biostudies-literature