To study the association of microbial translocation in patients with Parkinson’s disease in Zambia.

Over the past few years evidence has emerged that Parkinson’s disease (PD) could originate from the gastrointestinal tract. Gut leakiness in patients who are genetically susceptible to PD might be an important early component to initiation and progression of the disease. We hypothesized that markers of microbial translocation might be elevated in persons that suffer from PD.

We conducted a case control study at the University Teaching Hospital in Lusaka, Zambia between October 2019 and March 2020. We enrolled 22 PD patients and compared them to 44 unmatched controls from the PD patient household or non-household individuals. We measured 16S ribosomal RNA (16S rRNA) gene copy number, by quantitative real-time polymerase chain reaction.

The 16S rRNA gene copy number was dichotomized at 2 for both PD and the control groups. At 16S rRNA gene copy > 2 no significant difference was found between the two groups (11.36%, controls vs 0% in PD cases, p= 0.12, by Fisher’s exact test). However on sensitivity testing (16S rRNA ≥ 2), controls had higher copy numbers (25% vs 0%, p= 0.007).

The PD participants were older than controls, [median age of 69.5 years (IQR: 63-75) vs 47years (IQR: 37–56), p< 0.001, by Kruskall-Wallis test]. They also had slower bowel transit time (median bowel movements/week, 3 vs 5.7, p=0.017) and were more likely to have mild cognitive impairment, [median mini mental state exam score 25.5, (IQR: 18-29) vs 29, (IQR: 26.5-30) p= 0.002)].

The data suggests that patients with PD have low to undetectable levels of 16S rRNA, comparable to controls. This similarity could be accounted for by similarities in the environments of the participants. Further study into other markers of microbial translocation is needed.