Don’t be grossed out: This is a story in part about, well, poop. Three healthy adults collected weeks of stool samples so that scientists could count exactly how two separate rounds of a fairly mild antibiotic caused a surprising population shift in their microbial netherworld — as some original families of germs plummeted and other types moved in to fill the gap.
It’s also a story of how we coexist with trillions of bacteria, fungi, and other microbes in the skin, nose, digestive tract, what scientists call the human microbiome.
Many are beneficial, even indispensable, especially the gut bacteria that play an underappreciated role in overall health.
“Gut communities are fundamentally important in the development of our immune system,’’ explained Dr. David Relman of Stanford University, who led the antibiotic study published Monday in Proceedings of the National Academy of Sciences. “Let’s not take them for granted.’’
Next, Relman plans to track whether antibiotics used during the first year or two of life, when youngsters form what will become their unique set of gut bacteria, seem to predispose children later to immune-related diseases.
Antibiotics already should be used cautiously because they can spur infection-causing bacteria to become drug-resistant. The new research raises different questions about effects on beneficial bacteria.
“We should start paying attention to this,’’ said Dr. Martin Blaser, a microbiome specialist at New York University Langone Medical Center, who was not involved with Relman’s work but also is planning to study the issue in children. “The main point is that antibiotic use is not free in a biological sense.’’
