CDC Report Finds Brain-Infecting Mold Cases Rising at One Lab as Drug-Resistant Candida auris Spreads in Hospitals

Since British officials called the CDC in the winter of 2015 about a yeast they could not remove from a London hospital, Candida auris has gone from oddity to a standing agenda item for the people who study fungi. This fall, a second fungal problem has joined it.

A rare brain mold is showing up more often

A new CDC report describes Cladophialophora bantiana, a dark, yeast-like mold that can infect the brain. Between January 2009 and July 2026, researchers identified 48 confirmed cases and one probable case in tissue samples from 21 states and the District of Columbia. The median patient age was 68.

Data from a University of Washington microbiology lab shows detections nearly quadrupled between 2023 and 2025. From 2009 through 2023 the lab found one to five cases a year. The CDC says the count hit eight in 2024 and 14 in 2025.

Researchers checked whether more testing explained the jump. It did not appear to. Detections rose from 8.4 per 1,000 brain tissue specimens in 2017 to 2023 to 26 per 1,000 in 2025.

The infection is brutal. A systematic review in Medical Mycology put the fatality rate at 60% to 70% even with aggressive treatment. About half of cases occur in otherwise healthy people, unlike many fungal infections that mostly hit those with weakened immune systems.

Researchers believe the mold gets in through inhalation or a skin wound and then travels through the blood to the brain. Of the cases, 88% were found in brain tissue and 12% in lung tissue, which fits the inhalation theory.

The CDC report says plainly: "Reasons for the apparent increase are unknown." It calls for systematic national reporting and urges clinicians to consider fungal causes when they see brain abscesses. The numbers come from one lab's samples, so they show a trend there, not a national count. That is the point of the reporting request.

Candida auris keeps its hold on hospitals

C. auris was first identified in 2009 in a patient's ear in Japan. Later testing of older samples traced it to South Korea as far back as 1996. It has since sickened tens of thousands of people in more than 80 countries on six continents.

The CDC ranks it an "urgent threat," its highest alert level for a microbe. Invasive infections carry mortality rates of 30% to 60% among hospitalized patients.

It behaves unlike most fungi. It clings to skin and to slick hospital surfaces, survives for weeks or longer on them, and resists many antifungal drugs. Common cleaners, including quaternary ammonium compounds, do not reliably kill it. It spreads through direct contact and through contaminated curtains, floors, cellphones and blood pressure cuffs.

Most people who carry it never get sick. Those who are colonized can stay that way indefinitely, and can still spread it to equipment and other patients. A persistent fever that does not respond to antibiotics can signal a fungal infection, since antibiotics do nothing against fungi.

Dr. Tom Chiller, who ran the CDC's fungal-diseases branch in 2015, said he had never seen a life-threatening fungus spread so easily between people. "We realized that, huh, maybe this little ear fungus isn't just a little ear fungus anymore," he said.

About 200 doctors and researchers met near Denver in September for a three-day fungal-disease conference, and C. auris led the agenda. "Almost everyone who works in mycology is here," said Dr. Luis Ostrosky-Zeichner, an infectious-disease specialist at UTHealth Houston.

Why is this happening?

No one has a settled answer. Dr. Arturo Casadevall, chair of molecular microbiology and immunology at Johns Hopkins, argues that a warming planet and shifting human physiology are letting fungi breach human defenses. He warns that "humanity is not prepared for a fungal pandemic." Casadevall also says overuse of antifungal chemicals in agriculture may be helping fungi evolve resistance before they ever infect a person.

His point about timing: C. auris emerged around the same few years in South America, South Africa and the Indian subcontinent, and the isolates were unrelated, he says.

A review by Carla Schuh and Chaitanya Gokhale at Germany's University of Würzburg explores the heat link. Human body temperature, about 98.6°F, keeps out most fungi. C. auris grows readily at that temperature, and some samples survive up to about 117°F. Schuh and Gokhale pull together earlier research on whether warming helped it adapt. Their paper does not prove climate change caused its emergence.

The two organisms also differ. C. auris is a hospital problem that moves person to person. C. bantiana appears to come from the environment, and no source describes it spreading between people. The two should not be treated as one threat.

What comes next

The immediate question is data. No national system tracks C. bantiana cases, so the CDC cannot say whether the University of Washington pattern is local or widespread. Public health officials are asking for national case reporting, and no timeline for it has been announced.

The unanswered question is what is driving the C. bantiana rise. The CDC says the cause is unknown.