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. Author manuscript; available in PMC: 2019 Jun 13.
Published in final edited form as: Cell Host Microbe. 2018 Jun 13;23(6):737–748. doi: 10.1016/j.chom.2018.05.008

Figure 3. Changes in dietary metal availability alter the microbiota and susceptibility to pathogen colonization.

Figure 3

Under homeostatic conditions, a diverse commensal microbiota typically provides colonization resistance against multiple bacterial pathogens. Low zinc or high iron in the diet reduces overall commensal bacterial diversity along with key members of a healthy gut such as the Verrucomicrobia. This allows for an increase in abundance of members of the Enterobacteriaceae, many of which are pathogenic and encode high affinity metal transporters and siderophores to obtain nutrient metals. High zinc also disrupts the microbiota, reducing the amount of antibiotics needed to allow for C. difficile colonization and disease. Neutrophils recruited during C. difficile infection release calprotectin to sequester extracellular zinc, but the immune protein is overwhelmed with excess dietary zinc and is not effective at limiting zinc access to C. difficile.