Table 1.

Several bacterial and prokaryotic phyla are implicated in dysbiotic processes related to the onset of neurodegenerative diseases. The Akkermansiaceae and Prevotellaceae families are increased in Alzheimer’s, Parkinson’s, and ALS patients. Likewise, prokaryotic Bacteroidiaceae families are present in AD and ALS. In contrast, the Lachnospiraceae and Peptostreptococcaeae are respectively less numerous in these diseases. Opposite patterns of bacterial abundance were found in the Bifidobacteriaceae families between AD and ALS; in the Oscillospiraceae, and in Lactobacillaceae between PD and ALS [23,30,42].

Neurodegenerative Disease	Kingdom	Phylum	Class	Family	Alteration of Abundance	References
Alzheimer’s disease	Bacteria	Verrucomicrobiota Bacteroidota Proteobacteria Bacteroidota Actinobacteria Firmicutes	Verrucomicrobiae Bacteroidia Gammaproteocbacteria Bacteroidia Actinobacteria Clostridia	Akkermansiaceae Prevotallaceae Enterobacteriaceae Bacteroidiaceae Bifidobacteriacedae Lachnospiraceae	+ + + + − −	[23,25,27]
Amyotrophic lateral sclerosis	Bacteria	Verrucomicrobiota Bacteroidota Actinomycetota Firmicutes Bacteroidota Firmicutes Actinobacteria Firmicutes	Verrucomicrobiae Bacteroidia Coriobacteria Clostridia Bacteroidia Bacilli Actinobacteria Clostridia	Akkermansiaceae Prevotellaceae Coriobacteriaceae Oscillospiraceae Bacteroidiaceae Lactobacillaceae Bifidobacteriaceae Peptostreptococcaeae	+ + + + + + + −	[42,43]
Parkinson’s disease	Bacteria	Verrucomicrobiota Bacteroidota Firmicutes Firmicutes Firmicutes Firmicutes	Verrucomicrobiae Bacteroidia Clostridia Bacilli Clostridia Clostridia	Akkermansiaceae Prevotellaceae Oscillospiraceae Lactobacillaceae Lachnospiraceae Clostridiaceae	+ + − − − −	[30,31,32]