Topology of gut Microbiota Network and Guild-Based Analysis in Chinese Adults

Gut microbiota with co-abundant behaviors is considered belonging to the same guild in micro-ecosystem. In this study, we established co-abundance networks of operational taxonomic units (OTUs) among 2944 Chinese adults from the Shanghai Men's and Women's Health Studies and observed a positive connection-dominated scale-free network using Sparse Correlations for Compositional data (SparCC). The closeness centrality was negatively correlated with other degree-based topological metrics in the network, indicating the isolated modularization of the bacteria. A total of 130 guilds were constructed, with a high modularity of 0.68, and retaining more diversity of OTUs than genus classification. The scores of guild structure similarity for comparisons between all, the healthy and the unhealthy subjects were higher than those derived from randomized permutations, suggesting a robust guild structure. We further used the constructed 130 guilds as the aggregation units to identify gut microbiota that may be associated with type 2 diabetes, and found that the OTUs in 21 significant guilds relevant to diabetes belonged to 19 of 41 (46.3%) previously reported genera (derived from Disbiome database), while only 10 (24.4%) showed different abundances between diabetes patients and healthy subjects in genus-based analysis. Our study reveals modularization of gut microbiota as guilds in Chinese populations, and demonstrates advantages of guild-based analysis in identifying diabetes-related gut bacteria. The analytical method based on microbial networks should be widely used to deepen our understanding of the role of gut microbiota in human health.