How Commensal Gut Bacteria Keep Pathogens in Check

Recent studies describe how resident microbiota appear to outcompete unwelcome visitors, either with superior weaponry or by guzzling up local resources.

Written byAlejandra Manjarrez, PhD
| 7 min read
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The gut’s natural inhabitants are key to preventing and fighting some infections. Take Clostridioides difficile, a bacterium causing severe diarrhea that can be life-threatening: it is more likely to cause infection in a gut with an altered microbiota, often due to antibiotic treatment. Conversely, fecal microbiota transplants from healthy donors have proven useful to treat the disease, further evidence for the role of commensal bacteria in warding off the infection.

How commensals fight against such pathogens is beginning to come into focus. Warfare—through toxic compounds or other weaponry—and competition for resources are two common strategies. Now, a trio of studies published this month lends insight into how specific commensals might keep the gut safe from colonization by pathogens using these tactics. Together, the findings hold promise for the future design and prescription of probiotics to help ward off infectious diseases.

Together with her colleagues, Melanie Blokesch, ...

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Meet the Author

  • alejandra manjarrez

    Alejandra Manjarrez is a freelance science journalist who contributes to The Scientist. She has a PhD in systems biology from ETH Zurich and a master’s in molecular biology from Utrecht University. After years studying bacteria in a lab, she now spends most of her days reading, writing, and hunting science stories, either while traveling or visiting random libraries around the world. Her work has also appeared in Hakai, The Atlantic, and Lab Times.

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