Progression of Parkinson's disease is associated with gut dysbiosis: Two-year follow-up study

PLoS One. 2017 Nov 1;12(11):e0187307. doi: 10.1371/journal.pone.0187307. eCollection 2017.


Background: We previously reported gut dysbiosis in patients with Parkinson's disease (PD).

Objective: The aim of this study is to examine whether gut dysbiosis correlates with the progression of PD.

Methods: We examined changes in gut microbiota and demographic features in 2 years in 36 PD patients.

Results: A change of total UPDRS scores in 2 years was predicted by the counts of Bifidobacterium and Atopobium cluster at year 0 with a correlation coefficient of 0.52. Correlation analysis additionally revealed that low counts of Bifidobacterium and Bacteroides fragilis at year 0 were associated with worsening of UPDRS I scores in 2 years. In addition, low counts of Bifidobacterium at year 0 were associated with worsening of hallucinations/delusions in 2 years. Similarly, low counts of B. fragilis at year 0 were associated with worsening of motivation/initiative in 2 years. The patients were evenly divided into the deteriorated and stable groups based on the degree of worsening of total UPDRS scores. The deteriorated group had lower counts of Bifidobacterium, B. fragilis, and Clostridium leptium than the stable group at year 0 but not at year 2, suggesting that the deteriorated group may demonstrate accelerated lowering of these bacteria at year 0.

Conclusions: The total counts of intestinal bacterial decrease in the course of PD progression. Temporal profiles of lowering of bacterial counts are likely to be different from bacteria to bacteria, and also between the deteriorating and stable groups, which may be able to be exploited to differentiate patients with rapidly and slowly progressive PD pathology.

MeSH terms

  • Aged
  • Bacteroides fragilis / isolation & purification
  • Bifidobacterium / isolation & purification
  • Clostridium / isolation & purification
  • Colony Count, Microbial
  • Disease Progression
  • Dysbiosis / microbiology*
  • Female
  • Follow-Up Studies
  • Gastrointestinal Microbiome*
  • Humans
  • Male
  • Middle Aged
  • Parkinson Disease / microbiology*

Grant support

The authors acknowledge funding by the Japan Society for the Promotion of Science (JP) (24500458, 15H04840) (, the Japan Agency for Medical Research and Development (JP) (17gm1010002h0002) (; and Smoking Research Foundation (JP) ( The Yakult Central Institute provided support in the form of salaries for HT and KN, but did not play any further role in study design, data collection and analysis, decision to publish, or preparation of the manuscript. HT and KN blindly quantified intestinal microbiota, and were not involved in the data analysis. HT and KN provided essential experimental information, but did not affect the results and interpretation of our study.