Old European Drug Nitroxoline Beats "Brain-Eating" Amoeba

A decades-old drug used to treat urinary tract infections (UTIs) appears to have saved the life of a man infected by the “brain-eating” amoeba — and his case highlights the tremendous potential of a new type of genetic sequencing technology, Kristin Houser reported for BigThink.

Photo Insert: Nitroxoline is a broad-spectrum antimicrobial agent.

The patient: In 2021, a 54-year-old man was admitted to a Northern California hospital following a seizure. After an MRI revealed a mass in his brain, he was transferred to the UCSF Medical Center, where the mass was biopsied.

Based on the biopsy, doctors suspected that the patient’s brain was being attacked by an amoeba — a highly dangerous and unusual infection.

They sent a sample to the University of Washington, Seattle, where a PCR test identified the pathogen as Balamuthia mandrillaris — a deadly brain-eating amoeba that kills more than 90% of people it infects.

With the man showing signs of several brain lesions, the team started him on an intense regimen of antiparasitic, antibacterial, and antifungal drugs. “It’s what’s recommended because it was what happened to be used in patients who survived,” Natasha Spottiswoode, leader of the patient’s medical team, told Science Magazine.

After two weeks, the man’s lesions had shrunk slightly, but he began experiencing severe side effects from the treatment. The team cut back on his meds, and two weeks later, his lesions were growing again.

Within a week of treatment, his lesions began shrinking, and he was soon discharged. Spottiswoode came across a 2018 study in which UCSF biochemist Joseph DeRisi screened more than 2,000 compounds in the hope of finding one that would be effective against Balamuthia.

DeRisi’s team did find one candidate — an antibiotic called “nitroxoline.” Nitroxoline has been prescribed for UTIs in Europe for about 50 years, but isn’t approved in the US, so Spottiswoode had to reach out to the FDA for permission to administer it to her patient.

Once that was settled, she had to track down the medication — Chinese biotech company Asieris Pharmaceuticals, which is studying its use as a bladder cancer treatment, agreed to provide the pills, pro bono. It worked to defeat the brain-eating amoeba, which afflicted only 200 people since it was identified in 1986.

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