Antibiotic resistance discovered in the guts of ancient mummies

The gut bacteria inside 1000-year-old mummies from the Inca Empire are resistant to most of today’s antibiotics, even though we only discovered these drugs within the last 100 years.

“At first we were very surprised,” Tasha Santiago-Rodriguez of California Polytechnic State University in San Louis Opisbo, told the Annual Meeting of the American Society for Microbiology last month.

Her team studied the DNA within the guts of three Incan mummies dating back to between the 10th and 14th centuries and six mummified people from Italy, from between the 15th and 18th centuries. They found an array of genes that have the potential to resist almost all modern antibiotics, including penicillin, vancomycin and tetracycline.

These ancient genes were largely in microbes whose resistance is problematic today, including Enteroccocus bacteria that can infect wounds and cause urinary tract infections. But they found that many other species, including some harmless ones, carried some of these resistant genes too.

“When you think about it, almost all these antibiotics are naturally produced, so it makes sense to find antibiotic genes as well,” says Santiago-Rodriguez.

Their finding shows that genes that can confer resistance to antibiotics were relatively widespread hundreds of years before Alexander Fleming discovered penicillin in 1928. “It’s ridiculous to think evolution of antibiotic resistance began when penicillin was discovered,” said team-member Raul Cano, also at California Polytechnic State University, at the meeting while discussing the findings. “It’s been going on for 2 billion years.”