06 Sep 2011 Antibiotic resistance an ancient trait

Scientists were surprised at how fast bacteria developed resistance to antibiotic drugs when they were developed less than a century ago. Now, scientists at McMaster University in Ontario have found that antibiotic resistance has been around for at least 30 000 years.

Research findings published Aug 31 in the scientific journal Nature show that antibiotic resistance is a natural phenomenon that predates modern clinical antibiotics.

Principal investigators for the study were Gerry Wright, scientific director of the Michael G DeGroote Institute for Infectious Disease Research, and Hendrik Poinar, McMaster evolutionary geneticist.

“Antibiotic resistance is seen as a current problem, and the fact that antibiotics are becoming less effective because of resistance spreading in hospitals is a known fact,” Wright said. “The big question is” Where does all of this resistance come from?”

After years of studying bacterial DNA extracted from soil frozen in 30 000-year-old permafrost from the Yukon Territories, the researchers were able to develop methods to isolate DNA within McMaster University’s Ancient DNA Centre. Using state-of-the-art molecular biological techniques, methods were developed to tease out small stretches of ancient DNA.

The researchers discovered that antibiotic-resistant genes existed alongside genes that encoded DNA for ancient life, such as mammoths, horses and bison as well as plants only found in that locality during the last interglacial period in the Pleistocene era, which occurred at least 30 000 years ago.

They specifically focused on antibiotic resistance to the drug vancomycin – a significant clinical problem that emerged in the 1980s and continues to be associated with outbreaks of hospital-acquired infections worldwide.

Wright said the breakthrough will have an important impact on understanding antibiotic resistance.

“Antibiotics are part of the natural ecology of the planet, so when we think that we have developed some drug that won’t be susceptible to resistance or some new thing to use in medicine, we are completely kidding ourselves. These things are part of our natural world, and therefore, we need to be incredibly careful in how we use them. Microorganisms figured out a way of how to get around them well before we even figured out how to use them,” Wright explained.