[permaculture] Mount Sinai Scientists Find Unprecedented Microbial Diversity in Isolated Amazonian Tribe Previously Unexposed to Antibiotics or Processed Foods

Lawrence London lfljvenaura at gmail.com
Fri Jul 31 00:06:41 EDT 2015

Mount Sinai Scientists Find Unprecedented Microbial Diversity in Isolated
Amazonian Tribe Previously Unexposed to Antibiotics or Processed Foods
*Released:* 17-Apr-2015 2:00 PM EDT

*Newswise — NEW YORK — April 17, 2015 /Press Release/* — Scientists from
the Icahn School of Medicine, collaborating with a multicenter team of U.S.
and Venezuelan researchers, have discovered the most diverse collection of
bacteria yet in humans among an isolated tribe of Yanomami Amerindians in
the remote Amazonian jungles of Venezuela. Bacterial diversity in the
Yanomami, previously unexposed to antibiotics or industrialized diets, was
found to be nearly double that of people living in industrialized
countries, and was also significantly higher than in other remote
populations moderately exposed to modern practices. The team published its
findings today in the journal *Science Advances*.

The results suggest that antibiotic usage or western diet are linked to the
reduced bacterial diversity observed in modern societies, and that this
loss of diversity happens quickly upon initial exposure to those practices.
“There is a gradient of bacterial diversity that appears to be inversely
correlated with exposure to modern practices, such as antibiotics,
C-section, or processed foods,” said Jose C. Clemente, PhD, Assistant
Professor of Genetics and Genomics at the Icahn School of Medicine at Mount
Sinai and first author of the study. “Even minimal exposure to these
practices greatly decreases diversity and removes potentially beneficial
bacteria from our microbiome.”

To date, the vast majority of studies on the human microbiome—the trillions
of bacteria harbored in the body that are essential to our well-being—have
focused on Western populations. “Characterizing the bacterial communities
of non-Western, unexposed populations is essential to understand how the
microbiome changes and adapts to westernization,” said Dr. Clemente, “and
how those changes might be driving the increased incidence of diseases
linked to imbalances in the microbiome.”

The Yanomami villagers of this study, who have subsisted as
hunters-and-gatherers for hundreds of generations, are believed to have
lived in total seclusion from Western civilization until 2009 when they
were first contacted by a medical expedition. Among a rare population of
people unexposed to modern antibiotics, the villagers offer a unique window
onto the human microbiome.

“We have found unprecedented diversity in fecal, skin, and oral samples
collected from the Yanomami villagers,” said Maria Dominguez-Bello, PhD,
Associate Professor of Medicine at NYU Langone Medical Center and the
senior author of the study. “Our results bolster a growing body of data
suggesting a link between, on the one hand, decreased bacterial diversity,
industrialized diets, and modern antibiotics, and on the other,
immunological and metabolic diseases—such as obesity, asthma, allergies,
and diabetes, which have dramatically increased since the 1970s,” said Dr.

The analysis of gut and oral bacteria also revealed that the Yanomami
villagers had bacteria encoding antibiotic resistance genes, despite their
lack of previous exposure to antibiotics. Surprisingly, the bacterial genes
conferred resistance not only to natural antibiotics, such as those
produced by soil microbes, but also to synthetic antibiotics.

“During the 1940s and 1950s, in the heyday of pharmaceutical antibiotic
development, most antibiotics were derived from naturally occurring
bacteria in the soil,” said co-author Gautam Dantas, PhD, Associate
Professor of Pathology, Immunology, and Biomedical Engineering at
Washington University School of Medicine. “So, we would expect that natural
resistance to antibiotics would emerge over millions of years of
evolution,” he said. “We didn’t expect to find resistance to modern
synthetic antibiotics.” The presence of resistance genes in microbiota
unexposed to antibiotics may help explain the rapid rate at which bacteria
develop resistance to new classes of antibiotics, noted Dr. Dantas.

“The results from this study have given us a much better understanding of
our microbial past,” said Dr. Clemente. “Characterizing now the functions
encoded in those bacteria that we are missing will provide further insights
into the mechanisms behind these immune and metabolic conditions, and
potentially guide us in the development of new therapeutics.”

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