Scientists warn of the spread of a gene that turns bacteria into antibiotic-resistant superbugs.

A gene called npmA2, capable of giving dangerous bacteria complete resistance to antibiotics that are vital when there is no alternative, is spreading worldwide, according to an international team of scientists led by the Complutense University of Madrid.

"npmA2 is like a ghost: almost no one knew of its existence, and yet, without making a fuss, it has begun to appear in different parts of the world and in bacteria that are already difficult to control," explained Dr. Bruno González-Zorn, professor in the Department of Animal Health at the Complutense University of Madrid and director of the study.

According to the results, published this Wednesday in Nature Communications, this virtually unknown gene is spreading through hospitals and farms, generating impossible-to-treat "superbugs." Specifically, researchers have detected it in strains from six countries and in human, animal, and environmental samples, confirming its global spread.

For this study, the experts analyzed nearly two million bacterial samples, confirming that this gene acts as a "genetic passport" that travels in a mobile fragment, acting as a Trojan horse, and embeds itself in various bacteria that already pose a risk.

For example, professionals have detected the gene in the bacterium Clostridioides difficile, which causes serious intestinal infections, and in Enterococcus faecium, which causes hospital-acquired infections with a 30 percent mortality rate in Spain. "The npmA2 gene makes these infections practically incurable," stated Dr. Carlos Serna, co-author of the study.

The authors emphasized that research into new strategies to combat infections and monitoring antibiotic use are now more urgent than ever. "If we don't act now, we are heading for an era where a simple infection will once again be fatal," González-Zorn warned.

Along with the Complutense University of Madrid, scientists from the Welcome Sanger Institute in Cambridge (United Kingdom), the Pasteur Institute in Paris (France), and research centers in the Netherlands and Australia participated in this study.