Gut microbiota in the Alzheimer’s disease (AD) patients and the control subjects. The relative abundance of the bacterial taxa in the feces from the control subjects and the AD patients classified in the stages GDS-3, GDS-4 and GDS-5. The data are the means ± the SEM; (n = 10, control subjects; n = 12, AD patients; 4 per stage). (A) The bacterial phylum. (B) The bacterial class and the family belonging to the Firmicutes phylum. (C) The genera belonging to the Firmicutes phylum. The ANOVA shows an effect (p < 0.05) between AD classified in the stages and the bacterial taxa. Tukey’s test: * p < 0.05 and ** p < 0.01. p, phylum; c, class; f, family; g, genus.