(EurekaAlert!) Scientists have found antibiotic resistance genes in the bacterial flora of a South American tribe that never before had been exposed to antibiotic drugs. The findings suggest that bacteria in the human body have had the ability to resist antibiotics since long before such drugs were ever used to treat disease.

The research stems from the 2009 discovery of a tribe of Yanomami Amerindians in a remote mountainous area in southern Venezuela. Largely because the tribe had been isolated from other societies for more than 11,000 years, its members were found to have among the most diverse collections of bacteria recorded in humans. Within that plethora of bacteria, though, the researchers have identified genes wired to resist antibiotics.

The study, published April 17 in Science Advances, reports that the microbial populations on the skin and in the mouths and intestines of the Yanomami tribespeople were much more diverse than those found in people from the United States and Europe. The multicenter research was conducted by scientists at New York University School of Medicine, Washington University School of Medicine in St. Louis, the Venezuelan Institute of Scientific Research and other institutions.

“This was an ideal opportunity to study how the connections between microbes and humans evolve when free of modern society’s influences,” said Gautam Dantas, PhD, associate professor of pathology and immunology at Washington University and one of the study’s authors. “Such influences include international travel and exposure to antibiotics.”

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