“…Also, inflammatory or Aβ-associated bacteria such as Erysipelotrichaceae ( Bäuerl et al, 2018 ; Ticinesi et al, 2019 ) and Proteobacteria ( Nagpal et al, 2019 ; Ticinesi et al, 2019 ; Nagu et al, 2021 ) increased in APP/PS1 mice, which play key roles in the pathogenesis of AD. Similarly, some differential metabolites have been reported to be AD-related, such as 8-hydroxy-2-deoxyguanosine, a marker of nucleic acid oxidation ( Mecocci et al, 2018 ; Cioffi et al, 2021 ), and beneficial substances, including 15-oxoETE ( Snyder et al, 2015 ), 12-oxo-9(Z)-dodecenoic acid ( Yang et al, 2021 ), arbutin ( Dastan et al, 2019 ), 18β-glycyrrhetinic acid ( Wagle et al, 2018 ), and n -oleoylethanolamine ( Xu et al, 2016 ). Here, several previously unidentified differential bacteria and fecal metabolites were discovered, and their roles in AD need to be explored in further studies.…”