Cobamide Sharing Is Predicted in the Human Skin Microbiome

Area of Science:

• Microbiology
• Human Health
• Metagenomics

Background:

• The skin microbiome plays a crucial role in human health, influencing immunity and barrier function.
• Understanding microbial interactions is key to deciphering skin microbiome structure and stability.
• Cobamides (vitamin B12 cofactors) are vital but produced by limited prokaryotes, suggesting community-level sharing.

Purpose of the Study:

• To conduct the first large-scale metagenomic analysis of cobamide biosynthesis and utilization in the human skin microbiome.
• To investigate the role of cobamides in mediating skin microbial community dynamics and host interactions.

Main Methods:

• Large-scale metagenomic sequencing of skin microbial communities.
• Analysis of cobamide biosynthesis and utilization pathways across skin taxa.
• Culturing and laboratory quantification of cobamide production by human skin-associated species.

Main Results:

• Numerous skin bacteria possess cobamide-dependent enzymes, but few can synthesize cobamides *de novo*.
• Cobamide producers and users are integrated within skin microbial networks across different body sites.
• Abundance of cobamide-producing *Corynebacterium* correlates with skin microbiome diversity and structure in health and disease.
• *De novo* cobamide biosynthesis is enriched in host-associated *Corynebacterium* species.

Conclusions:

• Cobamide sharing is a potential mechanism shaping skin microbial community dynamics.
• Cobamides may play a significant role in host-microbe interactions and maintaining skin health.
• *Corynebacterium* species are key players in skin cobamide metabolism and microbiome regulation.