Liping Zhao and colleagues, in their recent paper on a dietary intervention for simple and genetic obesity, discussed evidence for the existence of gut microbiota ‘guilds’: bacterial genomes within the gut ecosystem that responded to the dietary intervention as a group.

Zhao further explains to GMFH editors, “Guilds are functional groups formed by different species in an ecosystem. Members in the same guild co-thrive or co-decline together.”

A single bacterial species probably cannot hold membership in multiple guilds, and the species in a guild need not be taxonomically close to each other. Zhao notes, though, that guild membership is probably not rigid: “Under different perturbations, some functional interactions among members may change so that re-organizations may occur and you may see new guilds emerge.”

“One thing we should keep in mind is that [the] definition of guild is based on statistics of the co-occurrence patterns,” says Zhao.

He and his colleagues noted that a detailed (i.e. species-level) analysis was important for finding members of the 18 Genome Interaction Groups (GIGs) identified in their study.

Zhao says, “All guild delineations need to be validated eventually by mechanistic studies.” Understanding how bacteria form and maintain these groups could lead to important insights about ecological interactions among bacteria in the gut.

Zhao thinks the concept of guilds could apply broadly, to different areas of gut microbiota research. “This should be a general phenomenon in all microbial ecosystems, not just a special case for obesity-related microbiota,” he says.

In the future, guilds may be useful for identifying certain states of health or disease in humans.

See below a short video interview with Liping Zhao on diet, obesity, and quality FMT samples.

Zhang C, et al. (2015) Dietary Modulation of Gut Microbiota Contributes to Alleviation of Both Genetic and Simple Obesity in Children
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