Amino acid availability influences Staphylococcus aureus interaction with the nasal microbiota in a strain- and community-specific manner

BACKGROUND: Only some individuals carry Staphylococcus aureus in the nose, predisposing them to endogenous infections. While microbial cooperation and competition are known to shape environmental and intestinal microbial communities, their impact on pathogen colonization within the nasal microbiome is largely unknown. RESULTS: Using a newly curated nasal strain collection and systematic pairwise interaction analysis, we investigated competitive and collaborative traits between diverse S. aureus strains and nasal communities. Our experiments revealed that nasal species strongly modulate S. aureus growth in a strain- and community-specific manner both in vitro and in gnotobiotic mice. Nutrient-dependent interactions emerged as key drivers. In one example, we found that tyrosine provided by synthetic communities supported proliferation of an auxotrophic S. aureus strain. Screening of a large collection of S. aureus strains identified tyrosine dependency in 8% of strains, with colonization impaired in the absence of supportive communities, indicating broader relevance of this interaction. CONCLUSIONS: Our findings reveal distinct metabolic adaptations that enable S. aureus to exploit specific features of resident nasal communities, highlighting complex interspecies networks that influence colonization in the human nose. These insights may inform microbiome-editing strategies to displace S. aureus from the nasal niche. Video Abstract.