It’s worth noting that not every dire superbug prediction comes true. In the early 2000s, physicians were very alarmed when resistance to vancomycin—like colistin, another last-resort antibiotic preserved from the 1950s—moved via a plasmid from Enterococcus into Staphylococcus aureus, or staph. At the time, people were already worried about the better-known form of drug-resistant staph, MRSA; the emergence of VRSA, as it became known, ratcheted worries way up. In the end, though, VRSA turned out not to be much of a threat: In 15 years, there have been only 14 such infections in the United States.

But what makes MCR, this new colistin resistance, different from VRSA is the role that agriculture seems to be playing in its evolution and dispersal. There are two problems here. First, that thousands to millions of animals are getting the drug, which exponentially expands the opportunities that favor resistance. And second, that projects such as the Chinese one that allowed the new gene to be discovered are rare—so colistin resistance could begin moving, from animals and into people, without being noticed.

And, in fact, it may be on the move now. The authors note that, while they were writing up their findings, the European Molecular Biology Laboratory received five submissions of bacterial data that appeared to contain the MCR gene—but not from China; from Malaysia.