Scientists have found a secret 'switch' that lets bacteria resist antibiotics — and it's been evading lab tests for decades

An illustration showing rod-shaped bacteria on a purple background. A few of the bacteria are colored red.

In 2021, a man in his 50s was transferred to the intensive care unit at Emory University Hospital in Atlanta. He was in septic shock due to a bacterial infection that had spread to his bloodstream. The culprit? Klebsiella pneumoniae, which was resistant to most antibiotics.

Finally, hope emerged: A two-week course of an antibiotic called cefiderocol seemed to clear the infection. But just 10 days later, the man was rushed back to the ICU, where doctors discovered a pus-filled mass covering his liver. The same bacteria had returned with a vengeance.