More than 600 cases of the infection, which can be fatal if it gets into the bloodstream, have been reported.
The gene is resistant to one of the world's "last resort" antibiotics.
Nearly a dozen U.S. residents have returned with drug-resistant infections after getting medical procedures in Tijuana, the CDC said.
Soil found in Fermanagh, Northern Ireland, had long been reputed to have healing properties.
The bacteria is also resistant to almost all antibiotics, according to scientists
"It's yet another good reason to pack the condoms for the summer holidays—and actually use them," one doctor said.
Government health officials in England say a man in the U.K. picked up the world's "worst-ever" case of super-gonorrhea after a sexual rendezvous with a woman in southeast Asia.
The bacterium, known as CRE, kills as many as half of those infected.
Scientists have developed a new alternative to antibiotics that could revolutionise the way we treat superbugs and avoid a scenario in which people die from routine procedures