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bioRxiv · 10.1101/2025.03.24.644983

Evaluation of Probiotic Bacteria for the Reduction of Urea, p-Cresol, and Indole Levels

Hammer, S. S.·Avvaru, B.·Bahl, A.·Quay, S. C.
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Abstract

IntroductionEnd-stage kidney disease (ESKD) is associated with the accumulation of uremic toxins such as urea, p-cresol, and indole, which significantly contribute to systemic complications such as inflammation, oxidative stress, and gut dysbiosis. Probiotics have demonstrated potential in modulating gut microbiota and reducing these toxins. We evaluated the in vitro efficacy of multiple probiotic strains of Lactobacillus, Bifidobacterium, Sterptococcus, Bacillus and others in degrading urea, p-cresol, and indole. MethodsThe probiotic strains were initially trained on toxin media prior to their evaluation of their toxin breakdown efficiency. Additionally microbiological methods using selective Christiansons broth/agar and Stuarts broth/agar were applied to assess urea breakdown. Liquid Chromatography-Mass Spectrometry (LC-MS) was utilized to quantify p-cresol and indole degradation. ResultsThe results indicated that all probiotic strains exhibited significant activity in reducing urea, p-cresol, and indole concentrations in the culture media. In urea breakdown we observed an oscillation urea/ammonia ratio at 24 hr intervals, although a complete elimination of the ammonium byproduct was not feasible. Among all tested probiotics, Lactobacillus species showed the highest efficiency in urea breakdown. Furthermore, the toxin removing efficacy of the probiotics was evaluated in a simulated gut environment using the TNO invitro gut model. ConclusionCumulatively, the findings suggest that probiotics could offer a promising strategy for the reduction of uremic toxins and their associated complications in ESKD patients.

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Hammer, S. S., Avvaru, B., Bahl, A., Quay, S. C.. 2025-03-24. Evaluation of Probiotic Bacteria for the Reduction of Urea, p-Cresol, and Indole Levels. https://doi.org/10.1101/2025.03.24.644983

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