APP and Alzheimer disease: Notably, in the present study, alterations in the gut microbiota of WT recipient mice caused by transplanting the gut microbiota of AD patients and APP/PS1 mice were similar to those observed in the latter study, with a decrease in RA of Bacteroidetes and an increase in RA of Firmicutes, in contrast to the observations in the former study, which may be due to a different region and different interventions administered.