(P19-049-25) Shared Dynamics of the Colonic Microbiome Make Responses to Fiber Interventions Unexpectedly Consistent Among Individuals

Objectives: The microbiome is complex and personalized, yet it has been demonstrated that certain dynamics of the human gut microbiome are broadly shared among individuals. However, the effects of this shared rule set on outcomes of clinical importance has not been established. We hypothesized that shared dynamics, specifically referring to the growth rates of individual microbial taxa and the inter-taxa interaction coefficients, would translate to more consistent responses to a dietary intervention.

Methods: We analyzed data from 11 previous studies, encompassing 2,488 biological samples from 469 human participants. Within each study, we referenced each participant’s before and after-intervention samples to determine the log change of each microbial taxa. We then calculated the average log change of each taxa that was found in at least three donors, as well as the Standard Deviation (SD) of each change. Lastly, we conducted taxa-level randomization to computationally remove any shared dynamics, and then re-calculated the magnitude and SD of changes to all taxa. A recently-developed statistical technique called Dissimilarity-Overlap Curve Analysis (DOCA) was then used to verify whether the samples in the original and randomized datasets originated from microbiomes with shared dynamics.

Results: Out of 2,429 taxa-level changes that were quantified across the 11 studies in the dataset, 5.0% of all taxa changed by >0.5 log, 0.3% changed by >1 log, and 0.1% changed by >1.5 log. DOCA showed that the samples in our dataset had shared dynamics (p < 0.05) that were successfully removed by taxa-level randomization (Fns = 0.93 vs 0.06). Comparing the real and randomized datasets demonstrated that the changes to microbial taxa had an average SD of 0.42 log in the real data with preserved, shared dynamics vs 0.55 log in the randomized data which lacked the shared dynamics.

Conclusions: In this study we used meta analysis of a large dataset to show for the first time how certain fundamental dynamics of the gut microbiome are not only shared among individuals, but make the response to dietary interventions more consistent than would be expected in a system with random response.

Funding Sources: Clay Swackhamer is supported by a postdoctoral fellowship through the Agriculture and Food Research Initiative (Project No. IND01234567G) from the USDA National Institute of Food and Agriculture.