Gut bacteria recorded in the stomachs of Amazonian natives is revealing new information about the human microbiome — the complete makeup of microorganisms in the body. The finding was developed from a study of people living in remote regions of Venezuela.
Natives of this village were shown to have the greatest diversity of bacteria seen in any population in the world. Some of the bacteria found in the guts of these villagers exhibit genes that could make the microorganisms resistant to treatment with antibiotics, even synthetic ones. This is both surprising and alarming to researchers, as these people had rarely come in contact with humans from outside their area and had never taken commercial antibiotics.
The tribe of Yanomami Amerindians were first seen by westerners in 2009, after 11,000 years of isolation from the outside world. Investigators believe that this extreme isolation may have led to the development of the highly-diverse microbiome observed in the people living in the jungles of southern Venezuela.
Some of the bacteria seen in the Venezuelan villagers had never before been seen in human beings. Human bodies contain trillions of bacteria, many of which are beneficial, assisting in the digestion of food, fending off disease-carrying microbes and strengthening the immune system.
Data collected from 34 of the 54 Yanomami villagers was compared with the microbiome of Europeans, South Africans, Americans and the Guahibo people of the Venezuelan Amazon.
"Our study suggests that the pre-modern human microbiota was composed of a greater diversity of bacteria and a greater diversity of bacterial functions when compared to populations impacted by modern practices, such as processed foods and antibiotics," said Gautam Dantas of Washington University.
Yanomani natives were shown to have 30 percent to 40 percent more types of bacteria than other natives and twice as many as Americans. This may be due to the increase in diabetes, allergies, obesity and asthma seen in Americans over the last several decades. One type of bacteria found in the natives but not in most cultures appears to protect the body from kidney stones, an extremely painful condition that commonly affects Americans.
This new investigation also suggests that antibiotic-resistant bacteria was prevalent long before the development of antibiotics. Many health professionals blame the overuse of the drugs for spawning microorganisms resistant to the medicines.
The village where these natives live is so remote that it can only be accessed by helicopter. The people there, nomadic hunter-gatherers, possessed a few T-shirts, metal cans and machetes, showing they have had some contact with the outside world, although such exposure is believed to be extremely limited.
"We see this as one more piece of clear evidence that antibiotic resistance is indeed a natural feature of the human microbiota but that it's primed to be activated and amplified for greater resistance after antibiotic use," Dantas said.
Discovery of the highly-diverse microbiome of uncontacted Amerindians was published in the journal Science Advances.
Photo: Eric Pheterson | Flickr