Antibiotic resistance is nothing new

SMALL PRINT:TODAY WE think of antibiotic resistance in bacteria as a result of overusing certain drugs to treat infections. But a new study highlights that it may have been around for quite a while.

The findings, detailed in the open-access website PLoS One (plosone.org), came when scientists collected bacteria from Lechuguilla Cave in New Mexico. They grew samples taken from a region of the cave system that has been isolated for more than four million years, and tested them against various antibiotics.

“We report that, like surface microbes, these bacteria were highly resistant to antibiotics; some strains were resistant to 14 different commercially available antibiotics,” they write. This “supports a growing understanding that antibiotic resistance is natural, ancient and hard-wired in the microbial pangenome”.

The study demonstrates that antibiotic resistance exists in bacteria that have not been exposed to human sources of antibiotics, says Dr Jim O’Gara from University College Dublin’s Conway Institute, who was not involved in the study.

“This is unsurprising because bacteria like Streptomyces produce antibiotics in natural environments,” he says. “In order to survive, other bacteria existing in these environments need to be resistant to these antibiotics.”

The study also found previously undiscovered mechanisms of antibiotic resistance in the bacteria from the cave. “It suggests that bacterial populations in general have as-yet untapped mechanisms of resistance that they can deploy to overcome existing and indeed any new antibacterial drugs used clinically,” Dr O’Gara says.

This led the authors to suggest that their findings might represent an early warning for antibiotic resistance mechanisms we might encounter among human pathogens in the future.