Metabiosis underlies a microbiota permissive to Pseudomonadota and increases the risk of gut-borne bloodstream infection

. Guided by this insight, we used metagenomics to identify the PUL-encoded functions underlying the metabiotic potential of a patient's microbiota and establish a link to gut-derived Gram-negative bacteremia in allo-HCT. Together, our findings translate mechanistically based microbiome ecology into a clinically actionable framework for early risk stratification and intervention.