mdpi.com/2072-6643/14/2/355...
"5. Conclusions
These findings suggest that oral microbiota could be associated with the development of PD. Firmicutes and Actinobacteria dominated the oral cavity microbiome in both examined groups. Patients with PD stand out with a higher concentration of phylum Bacteroidetes, and the healthy controls were recognizable because of the significant participation of Proteobacteria."