MAPT and Alzheimer disease: Among genera that were more abundant in patients with AD and MCI (Bacteroides, Ruminococcus, Butyricimonas, Paraprevotella, and Sutterella), we observed a positive relationship between ASV abundance and AD and MCI pathology (increasing amyloid burden), as implied by positive correlations (t-value >0) with CSF p-tau/Aβ42 ratios.