IntroductionThe aggregation of the neuronal protein alpha-synuclein (alpha-syn) is a key feature in the pathology of Parkinson’s disease (PD). Alpha-syn aggregation has been suggested to be induced in the gut cells by pathogenic gut microbes such asDesulfovibriobacteria, which has been shown to be associated with PD. This study aimed to investigate whetherDesulfovibriobacteria induce alpha-syn aggregation.MethodsFecal samples of ten PD patients and their healthy spouses were collected for molecular detection ofDesulfovibriospecies, followed by bacterial isolation. IsolatedDesulfovibriostrains were used as diets to feedCaenorhabditis elegansnematodes which overexpress human alpha-syn fused with yellow fluorescence protein. Curli-producingEscherichia coliMC4100, which has been shown to facilitate alpha-syn aggregation in animal models, was used as a control bacterial strain, andE. coliLSR11, incapable of producing curli, was used as another control strain. The head sections of the worms were imaged using confocal microscopy. We also performed survival assay to determine the effect ofDesulfovibriobacteria on the survival of the nematodes.Results and DiscussionStatistical analysis revealed that worms fedDesulfovibriobacteria from PD patients harbored significantly more (P<0.001, Kruskal-Wallis and Mann-Whitney U test) and larger alpha-syn aggregates (P<0.001) than worms fedDesulfovibriobacteria from healthy individuals or worms fedE. colistrains. In addition, during similar follow-up time, worms fedDesulfovibriostrains from PD patients died in significantly higher quantities than worms fedE. coliLSR11 bacteria (P<0.01). These results suggest thatDesulfovibriobacteria contribute to PD development by inducing alpha-syn aggregation.