from Teresa Binstock
This study used a single high dose of streptomycin orally in one arm, and
low doses of several antibiotics in drinking water in another arm. The results
are quite dramatic:
"The most profoundly altered pathways involved steroid hormones, eicosanoid
hormones, sugar, fatty acid, and bile acid"
Antibiotics Disrupt Gut Ecology, Metabolism
ScienceDaily (Apr. 19, 2011) — Humans carry several pounds of microbes in our
gastro-intestinal tracts. Recent research suggests that this microbial ecosystem
plays a variety of critical roles in our health. Now, working in a mouse model,
researchers from Canada describe many of the interactions between the intestinal
microbiota and host, and show that antibiotics profoundly disrupt intestinal
homeostasis. The research is published in the April 2011 issue of the journal
Antimicrobial Agents and Chemotherapy.
"Intestinal microbes help us digest our food, provide us with vitamins that we
cannot make on our own, and protect us from microbes that make us sick, amongst
other things," says L Caetano M. Antunes of the University of British Columbia,
a researcher on the study. In this study, the investigators used powerful mass
spectrometry techniques to detect, identify, and quantify more than two thousand
molecules which they extracted from mouse feces. They then administered
antibiotics to the mice, to kill off most of their gut microbiota, and analyzed
the feces anew.
The second round of mass spectroscopy revealed a very different metabolic
landscape. The levels of 87 percent of the molecules detected had been shifted
up or down by factors ranging from 2-fold to 10,000-fold.
The most profoundly altered pathways involved steroid hormones, eicosanoid
hormones, sugar, fatty acid, and bile acid. "These hormones have very important
functions in our health," says Antunes. "They control our immune system,
reproductive functions, mineral balance, sugar metabolism, and many other
important aspects of human metabolism."
The findings have two important implications, says Antunes. "First, our work
shows that the unnecessary use of antibiotics has deleterious effects on human
health that were previously unappreciated. Also, the fact that our gut microbes
control these important molecules raises the possibility that manipulating these
microbes could be used to modulate diseases that have hormonal or metabolic
origins (such as inmmunodeficiency, depression, diabetes and others). However,
further studies will be required to understand exactly how our microbial
partners function to modulate human physiology, and to devise ways of using this
information to improve human health."
(L.C.M. Antunes, J. Han, R.B.R. Ferreira, P. Lolic, C.H. Borchers, and B.B.
Finlay, 2011. Effect of antibiotic treatment on the intestinal metabolome. Antim.
Agents Chemother. 55:1494-1503.)
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- The above story is reprinted (with editorial adaptations by ScienceDaily
staff) from materials provided by American
Society for Microbiology, via
EurekAlert!, a service of AAAS.
- L. C. M. Antunes, J. Han, R. B. R. Ferreira, P. Lolic, C. H. Borchers,
B. B. Finlay. Effect of Antibiotic Treatment on the Intestinal Metabolome.
Antimicrobial Agents and Chemotherapy, 2011; 55 (4): 1494 DOI:
Antimicrobial Agents and Chemotherapy, April 2011, p. 1494-1503, Vol. 55, No. 4
Copyright © 2011,
American Society for Microbiology. All Rights
Effect of Antibiotic Treatment on the Intestinal Metabolome
L. Caetano M. Antunes,1 Jun Han,2 Rosana B. R. Ferreira,1 Petra Loli
,1,3 Christoph H. Borchers,2, and B. Brett Finlay1,3*
Michael Smith Laboratories, The University of British Columbia, Vancouver,
British Columbia V6T 1Z4, Canada,1 University of Victoria Genome BC Proteomics
Centre, University of Victoria, Victoria, British Columbia V8Z 7X8, Canada,2
Department of Microbiology and Immunology, The University of British Columbia,
Vancouver, British Columbia V6T 1Z3, Canada3
Received 1 December 2010/ Returned for modification 8 January 2011/ Accepted 21
The importance of the mammalian intestinal microbiota to human health has been
intensely studied over the past few years. It is now clear that the interactions
between human hosts and their associated microbial communities need to be
characterized in molecular detail if we are to truly understand human
physiology. Additionally, the study of such host-microbe interactions is likely
to provide us with new strategies to manipulate these complex systems to
maintain or restore homeostasis in order to prevent or cure pathological states.
Here, we describe the use of high-throughput metabolomics to shed light on the
interactions between the intestinal microbiota and the host. We show that
antibiotic treatment disrupts intestinal homeostasis and has a profound impact
on the intestinal metabolome, affecting the levels of over 87% of all
metabolites detected. Many metabolic pathways that are critical for host
physiology were affected, including bile acid, eicosanoid, and steroid hormone
synthesis. Dissecting the molecular mechanisms involved in the impact of
beneficial microbes on some of these pathways will be instrumental in
understanding the interplay between the host and its complex resident microbiota
and may aid in the design of new therapeutic strategies that target these