The drug's promise was demonstrated in a recent case report, published in January in the journal Emerging Infectious Diseases(opens in new tab), which describes a 54-year-old man whose brain was infiltrated by the amoeba Balamuthia mandrillaris.

The single-celled organism lives in dust, soil and water, and can enter the body through skin wounds and cuts or through the lungs, when it's inhaled, according to the Centers for Disease Control and Prevention(opens in new tab) (CDC).

The amoeba can then infiltrate the bloodstream and travel to the brain, triggering a very rare infection called "granulomatous amebic encephalitis" that kills around 90% of people affected.

"It's what's recommended because it was what happened to be used in patients who survived," Dr. Natasha Spottiswoode(opens in new tab), an infectious disease physician-scientist at UCSF and first author of the case report, told Science.

In search of another solution, Spottiswoode dug up a 2018 report, published in the journal mBio(opens in new tab), in which UCSF scientists found evidence that an antibiotic called nitroxoline can kill B. mandrillaris in laboratory settings.

The patient was soon discharged from the hospital and he continued to take nitroxoline at home, along with other medications; his clinicians plan to eventually discontinue his use of the drugs.