Scientist said it that can turn almost any type of bacteria into a powerful superbug.
Even the strongest antibiotics are unable to treat these infections.
Doctors said new antibiotics are needed to tackle this problem, but they aren't being produced.
"We are not developing new drugs, and the few drugs in development are not going to handle our problem. We have a real crisis in antibiotic development right now," said Dr. Brad Spellberg of Harbor-UCLA Medical Center.
The gene was first discovered in India and Pakistan, but has now been seen in the U.S., Netherlands, Australia, Canada and the United Kingdom.
Scientists said the spread may be linked to tourists who receive medical care in India and Pakistan.