Targeted in vitro suppression of Parkinson's disease-associated Desulfovibrio by selective probiotic and potential probiotic strains.

INRODUCTION: Emerging evidence links fecal Desulfovibrio (DSV) abundance with Parkinson's disease (PD) severity. While probiotics may relieve symptoms, their direct effects on DSV remain unexplored.

METHODS

This study evaluated the inhibitory potential of 32 probiotic and potential probiotic strains against three DSV strains isolated from three individual PD patients. Antimicrobial activity was quantified using agar well diffusion and microplate assays, and the operational minimum inhibitory con centration (MIC₉₀) was determined based on the total crude dry matter content of cell-free supernatants (CFS).

RESULTS

All tested lactic acid bacteria (LAB) strains, except Limosilactobacillus reuteri Hambi410, inhibited DSV. Quantitative micro assay results showed that Lacticaseibacillus rhamnosus LGG exhibited the highest inhibition (up to 44.82% ± 8.31%) after neutralization and catalase treatment. Among the eight tested Bifidobacterium strains, Bifidobacterium bifidum CUL-17 and Bifidobacterium longum E-96664 exhibited inhibitory effects comparable to those observed in LAB. The MIC₉₀ values revealed that Lactobacillus acidophilus Hambi1448 and Lactiplantibacillus plantarum E98 were the most potent, with MIC₉₀ values ranging from 25.2 to 29.8 mg/mL. Spearman's correlation confirmed a significant inverse relationship between initial pH and inhibition zones (p < 0.001). Crucially, analysis of covariance (ANCOVA) demonstrated that strain specific inhibitory variations remained highly significant (p < 0.005) after statistically controlling for the confounding effect of acidification, which is consistent with the involvement of non-acidic bioactive metabolites. Probiotic Bacillus strains showed no direct inhibition but are discussed for their role in alleviating PD-related constipation.

DISCUSSION: These findings demonstrate that specific probiotics can target PD-derived DSV, offering a novel strategy for microbiome-based PD management.