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Updated: Aug 6, 2026

Guided Protocol for Fecal Microbial Characterization by 16S rRNA-Amplicon Sequencing
Published on: March 19, 2018
Fecal metagenomic profiling in patients with colorectal adenomas to characterize gut microbial composition and
Guo Zhili1, Liu Jie1,2, Xue Yuyue1
1Department of Oncology, Jiaxing Hospital of Traditional Chinese Medicine, Jiaxing University, Jiaxing, Zhejiang, China.
Objective:
To investigate differences in gut microbiota between patients with colorectal adenoma (CRA) and healthy individuals using metagenomic sequencing, and to analyze the correlation between microbial abundance and polyp diameter and number.
Methods:
Metagenomic sequencing was performed on fecal samples from 60 patients with CRA and 30 healthy controls. Species-level and functional analyses of the gut microbiome were conducted.
Results:
Metagenomic profiling revealed a distinct microbial signature in CRA. Statistical analysis identified significant differences in taxonomic composition between the two groups. Overall, 487 genes showed significant abundance differences. Among these, approximately 55.37% were significantly enriched in the adenoma group, suggesting specificity for CRA, while 175 genes were significantly reduced. Alpha diversity analysis indicated similar microbial richness and evenness between the groups, whereas beta diversity confirmed significant structural differences in the microbial community. KEGG enrichment analysis of the top 20 differentially abundant species showed that these microbes were primarily associated with metabolic pathways. The greater number of increased versus decreased genes implied a more pronounced expansion of pathogenic bacteria relative to the loss of beneficial bacteria. Linear discriminant analysis effect size (LEfSe) analysis indicated that Fusobacterium nucleatum, Alistipes, and Bacteroides fragilis could serve as diagnostic microbial biomarkers for CRA. LEfSe further identified 38 differentially abundant bacterial clades, with genera such as Bacteroides, Peptostreptococcus, and Parabacteroides enriched in patients. Finally, correlation analysis linked the abundance of specific microbial taxa with polyp number and diameter.
Conclusion:
This study confirms distinct gut microbiota profiles in patients with CRA compared with healthy individuals, highlights significant microbiome alterations associated with CRA, and reveals novel correlations between specific microorganisms and polyp characteristics, suggesting that microbial changes may contribute to adenoma development.
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