Airway microbiome dysbiosis in severe pneumonia: metagenomic evidence of pathogen expansion and commensal depletion

Our multicenter observational analysis suggests that severe pneumonia is associated with marked ecological disruption of the lower-airway microbiome, characterized by commensal loss, opportunist expansion, and fragmented interspecies networks, and with concurrent inflammatory and coagulative abnormalities. These hypothesis-generating findings warrant external validation in independent, multi-region cohorts and longitudinal sampling to test directionality and causality before informing clinical decision-making.