It’s common knowledge that a protective navy of bacteria normally floats in our intestinal tracts. Antibiotics at least temporarily disturb the normal balance. But it’s unclear which antibiotics are the most disruptive, and if the full array of “good bacteria” return promptly or remain altered for some time.
In studies in mice, University of Michigan scientists have shown for the first time that two different types of antibiotics can cause moderate to wide-ranging changes in the ranks of these helpful guardians in the gut. In the case of one of the antibiotics, the armada of “good bacteria” did not recover its former diversity even many weeks after a course of antibiotics was over.
The findings could eventually lead to better choices of antibiotics to minimize side effects of diarrhea, especially in vulnerable patients. They could also aid in understanding and treating inflammatory bowel disease, which affects an estimated 500,000 to 1 million Americans, and Clostridium difficile, a growing and serious infection problem for hospitals.
Normally, a set of thousands of different kinds of microbes lives in the gut – a distinctive mix for each person, and thought to be passed on from mother to baby. The microbes, including many different bacteria, aid digestion and nutrition, appear to help maintain a healthy immune system, and keep order when harmful microbes invade.
“Biodiversity is a well-known concept in the health of the world’s continents and oceans. Diversity is probably important in the gut microsystem as well,” says Vincent B. Young, M.D., Ph.D., senior author of the study, which appears in the June issue of Infection and Immunity.
The study results suggest that unless medical research discovers how to protect or revitalize the gut microbial community, “we may be doing long-term damage to our close friends,” says Young, assistant professor in the departments of internal medicine and microbiology and immunology at the U-M Medical School.
Mice, which normally develop a diverse set of microbes after being born without one, then were given either cefoperazone, a broad-spectrum cephalosporin antibiotic, or a combination of three antibiotics (amoxicillin, bismuth and metronidazole). The scientists then observed what changes in the gut microbiota occurred immediately after the antibiotics were stopped or six weeks following the end of treatment.
“Both antibiotic treatments caused significant changes in the gut microbial community. However, in the mice given cefoperazone, there was no recovery of normal diversity. In other mice given the amoxicillin-containing combination, the microbiota largely recovered, but not completely,” says Young.
However, Young’s team found that a little socializing sparked recovery in even the most severely affected mice. Some of the mice given cefoperazone soon recovered normal microbes after an untreated mouse was placed in the same cage. That wasn’t a complete surprise, since mice have a habit of eating the feces of their cage mates and therefore picked up normal gut microbes quickly.
Not a lesson applicable to humans? In patients with refractory antibiotic-associated diarrhea due to C. difficile, there have been limited trials of treatments using “fecal transplants” to replace lost gut microbiota. Although this is a pretty unpalatable treatment at first glance, the clinical response was quite remarkable, Young says.Implications
The findings will guide Young in related work in which he is using mouse models to examine how changes in the microbiota in the gut may influence how inflammatory bowel disease develops and progresses. The study will also inform ongoing research in his lab to gain insights into colitis associated with C. difficile infection. The Young laboratory recently published a study that demonstrates that long-term decreases in gut microbe diversity from repeated antibiotics are associated with recurring C. difficile infection in human patients.
Young cautions against concluding that popular probiotics supplements necessarily are safe and effective for everyone looking for a way to restore healthy gut microbes. An individual’s specific health needs and vulnerabilities have to be considered. “Probiotics may be part of the solution, but we don’t know that yet,” he says.Other authors are: first author Dionysios A. Antonopoulos, Ph.D. Department of Internal Medicine, University of Michigan; Susan M. Huse, Ph.D., Mitchell L. Sogin,Ph.D., and Hilary G. Morrison, Ph.D., Marine Biological Laboratory, Woods Hole, Mass.; and Thomas M. Schmidt, Ph.D., Michigan State University.
Anne Rueter | EurekAlert!
Further reports about: > Amoxicillin > C. difficile infection > Clostridium difficile > Ernst & Young > Infection > antibiotics > bismuth > cephalosporin antibiotic > good bacteria > harmful microbes invade > helpful guardians > immune system > immunity > inflammatory bowel disease > intestinal tracts > metronidazole > mouse model > recovery of microbiota
Multi-institutional collaboration uncovers how molecular machines assemble
02.12.2016 | Salk Institute
Fertilized egg cells trigger and monitor loss of sperm’s epigenetic memory
02.12.2016 | IMBA - Institut für Molekulare Biotechnologie der Österreichischen Akademie der Wissenschaften GmbH
A multi-institutional research collaboration has created a novel approach for fabricating three-dimensional micro-optics through the shape-defined formation of porous silicon (PSi), with broad impacts in integrated optoelectronics, imaging, and photovoltaics.
Working with colleagues at Stanford and The Dow Chemical Company, researchers at the University of Illinois at Urbana-Champaign fabricated 3-D birefringent...
In experiments with magnetic atoms conducted at extremely low temperatures, scientists have demonstrated a unique phase of matter: The atoms form a new type of quantum liquid or quantum droplet state. These so called quantum droplets may preserve their form in absence of external confinement because of quantum effects. The joint team of experimental physicists from Innsbruck and theoretical physicists from Hannover report on their findings in the journal Physical Review X.
“Our Quantum droplets are in the gas phase but they still drop like a rock,” explains experimental physicist Francesca Ferlaino when talking about the...
The Max Planck Institute for Physics (MPP) is opening up a new research field. A workshop from November 21 - 22, 2016 will mark the start of activities for an innovative axion experiment. Axions are still only purely hypothetical particles. Their detection could solve two fundamental problems in particle physics: What dark matter consists of and why it has not yet been possible to directly observe a CP violation for the strong interaction.
The “MADMAX” project is the MPP’s commitment to axion research. Axions are so far only a theoretical prediction and are difficult to detect: on the one hand,...
Broadband rotational spectroscopy unravels structural reshaping of isolated molecules in the gas phase to accommodate water
In two recent publications in the Journal of Chemical Physics and in the Journal of Physical Chemistry Letters, researchers around Melanie Schnell from the Max...
The efficiency of power electronic systems is not solely dependent on electrical efficiency but also on weight, for example, in mobile systems. When the weight of relevant components and devices in airplanes, for instance, is reduced, fuel savings can be achieved and correspondingly greenhouse gas emissions decreased. New materials and components based on gallium nitride (GaN) can help to reduce weight and increase the efficiency. With these new materials, power electronic switches can be operated at higher switching frequency, resulting in higher power density and lower material costs.
Researchers at the Fraunhofer Institute for Solar Energy Systems ISE together with partners have investigated how these materials can be used to make power...
16.11.2016 | Event News
01.11.2016 | Event News
14.10.2016 | Event News
02.12.2016 | Medical Engineering
02.12.2016 | Agricultural and Forestry Science
02.12.2016 | Physics and Astronomy