Abstract
An estimated 95-97% of Parkinson's disease (PD) cases are idiopathic, emphasizing the absence of a clear etiologic linkage for this debilitating, neurodegenerative, and progressive motor disease. Increasing evidence suggests a peripheral disease origin and the gradual transition of a pathological process along the gut-brain axis and olfactory routes into the brain. This disease pattern is reminiscent of an infectious process and suggests the presence of one or multiple infectious agents, such as bacteria, viruses, fungi, or prion-like proteins. This unusual paradigm, known as Braak's hypothesis, was first described by the scientist who developed the staging standard for cellular PD pathology and. Here, we describe a case where the small, anaerobic, Gram-positive Cutibacterium acnes was recurrently isolated from intraoperative spinal tissues in a patient with early-onset PD. C. acnes is also the bacterium that we previously isolated from cadaveric PD brain tissue. Both observations are consistent with Braak's hypothesis underscoring the importance of homeostasis and maintained immune-competence for healthy aging of the body and mind.