Table 1.

Microbes’ effects in Parkinson’s Disease.

Phylum	Genus	Change	Effects on Parkinson’s Pathophysiology	References
Bacteroidetes	Prevotella	Reduced	Reduced secretion of neuroprotective hydrogen sulfide into the gut lumen and decreased intestinal motility	[117,118,121,125]
	Bacteroides	Reduced		[119,126]
Firmicutes	Lactobacillus	Reduced	Less neuroprotective effects, unable to rescue dopaminergic neuron loss, Inability to downregulate MAO-B, Reduced BDNF and tyrosine hydroxylase expression	[34,97,119,121]
	Lactobacillus	Elevated	Deconjugates neuroprotective bile acids, TDCA and UDCA	[118,124,127,128]
	Clostridium	Reduced	Increased α-synuclein accumulation	[117,124,128,129]
	Enterococcus	Elevated		[122]
	Ruminococcus	Elevated	Ruminococcus Albus reduces ROS species, increases BDNF effects, and has associations with decreased neuroprotective bile acids	[120,121,127,130]
Actinobacteria	Bifidobacterium	Elevated	Confers neuroprotective effects on dopaminergic neuron loss	[97,121]
Verrucomicrobia	Akkermansia	Elevated	Mucin-degrading genus, increases LPS and microglial activity	[116,117,118,131]