Bacteria resistant to carbapenem, a last-resort antibiotic used to treat severe infections, have been discovered in farm animals and have the potential to spread to humans, according to a study published in the journal Antimicrobial Agents and Chemotherapy.

Researchers from Ohio State University first made the discovery while collecting environmental samples from a pig farm. The findings suggest that the antibiotic—which is illegal to use on animals—was used on or somehow transferred to livestock there.

The carbapenem-resistant organisms have been discovered in European and Asian livestock, however, this is the first time the bacteria has been found in the United States.

Though researchers “found no evidence that these organisms were entering the food supply,” lead author of the study Thomas Wittum stated that there is a major concern that the genetic mutation “could happen on this or other farms” and pork infected by carbapenem-resistant bacteria could end up on the market and infect humans.

The discovery supports experts’ belief that the wider trend of antibiotic misuse on animals is contributing to the rise of more powerful superbugs.

Dr. Wittum stated: “The spread of this particular resistant strain on this farm may be related to antibiotics used to treat sick pigs, for the same reason that resistant bacteria like these are present in human hospitals because of the way we treat sick people with antibiotics.”

According to Time, many “experts estimate that in 2050, 10 million people will die from infections that are resistant to antibiotics each year. The use of antibiotics in livestock animals contributes to the problem, as does the inappropriate—but common—overprescribing of antibiotics.”