The finding, may have implications for both the understanding of drug resistance and ways of preventing it.

The scientists involved collected 93 strains of bacteria from Lechuguilla cave, approximately 1300 feet deep, and found that all the strains collected were resistant to at least one antibiotic out of the 26 tested with some resistant to up to 14 different types, reported the Los Angeles Times.

The emergence of antibiotic-resistant bacteria has largely been attributed to overconsumption of the drugs by humans and animals.

Yet, given the age and isolation of the cave, said Time, drug resistance may also have other causes.

“Clinical microbiologists have been perplexed for the longest time. When you bring a new antibiotic into the hospital, resistance inevitably appears shortly thereafter, within months to years,” study leader Gerry Wright, a chemical biologist at McMaster University in Ontario, told National Geographic.