Nasal commensals reduce Staphylococcus aureus proliferation by restricting siderophore availability

Area of Science:

• Microbiome research
• Bacterial pathogenesis
• Human health and disease

Background:

• The human microbiome plays a critical role in health and disease.
• Antibiotic-resistant pathogens like methicillin-resistant Staphylococcus aureus (MRSA) can colonize the nasal cavity, increasing infection risk.
• Molecular mechanisms governing interactions within the nasal microbiome are poorly understood, particularly regarding iron acquisition via siderophores.

Purpose of the Study:

• To investigate the role of siderophore acquisition in Staphylococcus aureus nasal colonization.
• To explore siderophore-mediated interactions between S. aureus and other nasal bacteria.
• To understand the impact of inter-species competition and collaboration on pathogen proliferation in the nasal environment.

Main Methods:

• Screening of 94 nasal bacterial strains for siderophore production and consumption.
• In vivo assessment of siderophore acquisition's importance for S. aureus nasal colonization.
• Co-culture experiments to evaluate the effect of siderophore consumption on S. aureus growth.

Main Results:

• Siderophore acquisition is essential for S. aureus nasal colonization in vivo.
• 80% of screened nasal bacterial strains interact with S. aureus through siderophores.
• Non-pathogenic corynebacteria are significant consumers of S. aureus siderophores, reducing pathogen growth in an iron-dependent manner.

Conclusions:

• A complex network of siderophore-mediated interactions exists within the human nasal microbiome.
• Inter-species competition and collaboration involving siderophores significantly impact pathogen proliferation.
• These findings suggest potential for developing nasal probiotics to control S. aureus colonization.