Microbial Diversity and Community Structures Among Those With Moderate to Severe TBI: A United States-Veteran Microbiome Project Study.

Objective: To evaluate the association between distal moderate/severe traumatic brain injury (TBI) history and the human gut microbiome. Setting: Veterans Affairs Medical Center. Participants: Veterans from the United States-Veteran Microbiome Project (US-VMP). Veterans with moderate/severe TBI (n = 34) were compared with (1) Veterans with a history of no TBI (n = 79) and (2) Veterans with a history of no TBI or mild TBI only (n = 297).

Design: Microbiome analyses from 16S rRNA gene sequencing with gut microbiota function inferred using PICRUSt2. Main measures: α-Diversity and β-diversity of the gut microbiome, as well as taxonomic and functional signatures associated with moderate/severe TBI.

Results: There were no significant differences in gut bacterial α- and β-diversity associated with moderate/severe TBI status. No differentially abundant taxa were identified when comparing samples from moderate/severe TBI to those with no TBI or no TBI/mild TBI.

Conclusion: Results suggest that moderate/severe TBI-related changes to the gut microbiome do not persist for years postinjury.