Oral Flora Composition in Patients With Parkinson’s Disease and Dysphagia

Objectives: Background and Objectives: Few groups have assessed the oral bacteria of patients who have Parkinson’s disease (PD). Swallowing difficulty, known as dysphagia, is a common symptom of PD that changes the microenvironment of the oral cavity and likely alters subjects’ oral flora.
The goals of our study were to characterize and compare the oral flora of PD patients who exhibit dysphagia symptoms with those who do not. We also set out to compare these samples with age- and gender-matched healthy controls.
Methods: Methods: 30 healthy individuals and 30 patients with PD were included in this study. Subjects completed the RADBOUD swallowing inventory (Kalf et al., 2011), which rates severity of dysphagia. Hard and soft oral tissue swabs were collected. After bacterial-specific DNA polymerase chain reaction (PCR), DNA sequencing identified and quantified species. 16S rDNA data was used to identify the significant differences in the oral microbiota community structure.
Results: Results: Oral flora from hard tissue was significantly different than the oral flora from soft tissue. Streptococcus was significantly more abundant in PD patients compared to healthy controls (p<0.05). There were no differences in the overall structure of the microbiota community between dysphagia and non-dysphagia PD patients. However, three anaerobic bacillus species, namely Oribacterium, Lachnoanaerobaculum, and Alloprevotella, were significantly less prevalent in dysphagia PD patients (p<0.05).
Conclusions: Conclusions: We show that the oral microbiome is different between PD patients and healthy individuals. Additionally, we show that patients with PD who also exhibit dysphagia symptoms had a different oral flora composition than patients who did not have dysphagia. Dysphagia samples had lower quantities of 3 anaerobic bacillus species (p<0.05). Future studies may tell us what role these species have in maintaining a healthy oral cavity. This study is a significant first step towards understanding the oral biology of PD.