Exploring microbial interactions and communities in human gut under ulcerative colitis and colorectal cancer

Microbes play an important role in human gut ecosystems by building complex interactions. Some highly connected microbial taxa, called keystone species, influence ecosystems individually or through a combinatorial effect. Although previous studies have explored numerous microbial associations in different ecosystems, studies on gut microbial interactions remain insufficient. We have focused on exploring the important taxa and their associations with other microbes in the human gut under ulcerative colitis (UC) and colorectal cancer (CRC). We have applied a network-based approach to build microbial co-abundance networks from the gut microbiome. Our study has pointed out several important disease-associated microbes and their communities in co-abundance networks of UC and CRC. Although a good overlap is observed between the microbes of the two networks, a clear difference has been found in their co-abundance patterns. The global topology shows a change in the network connectivity, modularity and microbial combinatorics between these two disease conditions. Further we have identified several microbial pathways with beneficial functions in healthy gut but harmful potential in dysbiosis. Our study provides insight into alteration of the microbial co-abundance patterns and communities under two different disease conditions and extends our understanding of microbial interactions in the human gut.