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How antibiotics enable pathogenic gut infections

Study pinpoints ways to counter the effects of the antibiotics-driven depletion of friendly, gut-dwelling bacteria.

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A number of intestinal pathogens can cause problems after antibiotic administration, said Justin Sonnenburg, PhD, assistant professor of microbiology and immunology at the Stanford University School of Medicine, and the senior author of a study published in Nature.

"Antibiotics open the door for these pathogens to take hold. But how, exactly, that occurs hasn't been well understood," Sonnenburg said.

In the first 24 hours after administration of oral antibiotics, a spike in carbohydrate availability takes place in the gut, the study says. This transient nutrient surplus, combined with the reduction of friendly gut-dwelling bacteria due to antibiotics, permits at least two potentially deadly pathogens to get a toehold in that otherwise more forbidding environment.

In the past decade or so, much has been learned about the complex microbial ecosystem that resides in every healthy mammal's large intestine, including ours. The thousands of distinct bacterial strains that normally inhabit this challenging but nutrient-rich niche have adapted to it so well that we have difficulty living without them. They manufacture vitamins, provide critical training to our immune systems and even guide the development of our own tissues. Antibiotics decimate this gut-microbe ecosystem, which begins bouncing back within a few days but may take a month or more to regain its...

The full text of this article can be purchased from Informit.