Elucidating the human gut microbiota of healthy and CRC patients in Asian population via shotgun metagenomics approach

The gut microbiota is the densest microbiota compared to other sites in the human body. Together as a balanced gut community, their symbiotic relationship with humans help to maintain the host health via crucial involvement in various body mechanisms. This study reports a preliminary finding of a comparative study of gut microbiota in healthy subjects and colorectal cancer patients in Malaysia. To further understand the association of gut microbiota and health condition, we also incorporated the data from other populations available in the public domain namely China, India, and Japan. Taxonomic profiles constructed based on taxonomic observations, alpha and beta diversity, and linear discriminant analysis showed unique gut microbiota pattern for each country, and distinct between the different study conditions. Further analysis on the healthy and different CRC stages identified potential intermediate species that are discriminant in the gut microbiota of healthy to early stage CRC transition. Functional profiles of discriminant species for each country and study condition highlights several microbial pathways that indicates specific microbial activities in the gut microbiota. Taxonomic and functional profiles generated in this study successfully identified microbial species that are unique and discriminant in each population and study conditions. Hence, these findings may serve as an important resource for development of microbiome based biomarkers representing the Asia population.