LONDON — People traveling to India for medical procedures have brought back to Britain a new gene that allows any bacteria to become a superbug, and scientists are warning this type of drug resistance could soon appear worldwide.

Though already widespread in India, the new superbug gene is being increasingly spotted in Britain and elsewhere. Experts warn the booming medical tourism industries in India and Pakistan could fuel a surge in antibiotic resistance, as patients import dangerous bugs to their home countries.

The superbug gene, which can be swapped between different bacteria to make them resistant to most drugs, has so far been identified in 37 people who returned to the U.K. after undergoing surgery in India or Pakistan.

The resistant gene has also been detected in Australia, Canada, the U.S., the Netherlands and Sweden. The researchers say since many Americans and Europeans travel to India and Pakistan for elective procedures like cosmetic surgery, it was likely the superbug gene would spread worldwide.

In an article published online Wednesday in the journal Lancet Infectious Diseases, doctors reported finding a new gene, called NDM-1. The gene alters bacteria, making them resistant to nearly all known antibiotics. It has been seen largely in E. coli bacteria, the most common cause of urinary tract infections, and on DNA structures that can be easily copied and passed onto other types of bacteria.

The researchers said the superbug gene appeared to be already circulating widely in India, where the health system is much less likely to identify its presence or have adequate antibiotics to treat patients.

“The potential of NDM-1 to be a worldwide public health problem is great, and coordinated international surveillance is needed,” the authors wrote.

Still, the numbers of people who have been identified with the superbug gene remains very small.

“The spread of these multi-resistant bacteria merits very close monitoring,” wrote Johann Pitout of the division of microbiology at the University of Calgary, Canada, in an accompanying Lancet commentary.