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Updated: Sep 5, 2025

Microbiota Analysis Using Two-step PCR and Next-generation 16S rRNA Gene Sequencing
Published on: October 15, 2019
A Bayesian method for identifying associations between response variables and bacterial community composition
Adrian Verster1, Nicholas Petronella1, Judy Green2
1Bureau of Food Surveillance and Science Integration, Food Directorate, Health Products and Food Branch, Health Canada, Ottawa, Canada.
We developed a new Bayesian model (BRACoD) to accurately identify intestinal bacteria associated with physiological outcomes. This method improves upon existing techniques for analyzing complex microbiome data, offering more precise results for bacteria-host relationship studies.
Area of Science:
- Microbiome research
- Statistical modeling
- Host-microbiome interactions
Background:
- Understanding the relationship between intestinal bacteria and host physiology is crucial.
- Analyzing compositional abundance data of bacteria presents statistical challenges due to non-normal distribution.
- Existing methods may lack precision in identifying true bacterial contributors to physiological outcomes.
Purpose of the Study:
- To develop a robust statistical model for determining associations between bacterial abundances and continuous physiological measurements.
- To improve the accuracy and precision of identifying bacteria that directly influence host physiological outcomes.
- To address the challenges posed by compositional microbiome data in regression analysis.
Main Methods:
- Developed a fully Bayesian linear regression model named BRACoD (Bayesian Regression Analysis of Compositional Data).
- Employed Stochastic Search Variable Selection for identifying associated bacterial taxa.
- Validated the model using simulated communities and compared its performance against clr-LASSO and clr-SS methods.
Main Results:
- BRACoD demonstrated higher precision and true positive rates compared to clr-LASSO and clr-SS.
- A cut-off value of inclusion probability ≥ 0.3 optimized true positive rate while maintaining a false positive rate ≤ 5%.
- Analysis of rat fecal samples identified 47 operational taxonomic units associated with butyrate levels, including known butyrate-metabolizing bacteria.
Conclusions:
- BRACoD offers a more precise and accurate method for analyzing microbiome data and identifying bacteria associated with physiological outcomes.
- The model effectively distinguishes genuine bacterial contributors from those merely correlated, enhancing the understanding of bacteria-host relationships.
- BRACoD's ability to handle compositional data makes it suitable for microbiome research.
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