Cross‐Sectional Associations Between Gut Microbiota and Neuroimaging Changes in Post‐ COVID ‐19 Condition

Aim Neurological symptoms, including cognitive complaints and fatigue, are common in post‐COVID‐19 Condition (PCC), a complex multisystem disorder following SARS‐CoV‐2 infection. Although gut microbiota changes have been reported in PCC and linked to PCC‐associated neurological manifestations, its relationship to structural or functional brain changes remains unexplored. Methods In this cross‐sectional study, the gut microbiota composition of 42 post‐COVID patients (29 females, 46.7 ± 11.3 years) and 30 healthy controls (22 females, 53.9 ± 17.8 years) was analyzed using 16S rRNA gene amplicon sequencing. Taxa that differed significantly in relative abundance, determined by linear discriminant analysis, were examined for their associations with self‐reported symptoms, neuropsychological measures, inflammatory and neuronal‐injury markers. Previously identified structural and functional brain changes in post‐COVID patients using magnetic resonance imaging were further correlated with relevant taxa. Results At 9 months post‐infection, gut microbiota differed significantly from that of healthy controls. We found a lower relative abundance of butyrate‐producing taxa. A lower relative abundance of Blautia faecis and Anaerobutyricum hallii was linked to diabetes. Bilophila wadsworthia was associated with lower sleep quality and cognitive fatigue. B. wadsworthia , Odoribacter splanchnicus , Coprococcus eutactus , and Streptococcus thermophilus were associated with altered structural and functional brain regions, including the brainstem, the thalamus, the hippocampus and the basal ganglia. Conclusion Our study provides evidence linking microbiota dysbiosis in PCC to symptoms and cerebral alterations, possibly related to depletion of health‐promoting taxa. Future research should investigate the causality of these findings and explore whether microbiome‐targeted therapeutic interventions might be associated with improvements in neurological symptoms and brain recovery.