A drug-resistant fungus is spreading in US hospitals—here’s what you need to know

Candida auris is deadly in sick patients with weakened immune systems.
Candida auris in a petri dish taken in a laboratory of Wuerzburg University in Wuerzburg, Germany, January 23, 2018.
Candida auris in a petri dish taken in a laboratory of Wuerzburg University in Wuerzburg, Germany, January 23, 2018. Nicolas Armer/DPA/picture alliance via Getty Images

We aren’t in an apocalyptic The Last of Us scenario, but there’s still plenty of fungus to be wary of. The Centers for Disease Control and Prevention (CDC) announced on March 20 that a deadly and highly drug resistant fungus is spreading at “an alarming rate” in nursing homes, long-term care hospitals, and other medical facilities that treat very sick patients.

Data from the CDC shows that infections from Candida auris (C. auris) tripled nationally from 476 infections in 2019 to 1,471 in 2021. Additionally, cases where a person carries the fungus but is not infected almost quadrupled from 1,077 in 2019 to 4,040 in 2021. Their early data suggests that these numbers have continued to increase. The CDC’s findings were published in a paper in the Annals of Internal Medicine on March 21

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“The rapid rise and geographic spread of cases is concerning and emphasizes the need for continued surveillance, expanded lab capacity, quicker diagnostic tests, and adherence to proven infection prevention and control,” Meghan Lyman, a CDC epidemiologist and co-author of the new paper, said in a press release.

The fungus primarily affects older patients with weakened immune systems. However, the fungus is resistant to some common antifungal medications, making it particularly dangerous.  A 2020 report found that 86 percent of the germ samples tested by the CDC were resistant to a broad class of drugs known as Azoles. Additionally, 1.3 percent of C. auris samples were resistant to echinocandins. These drugs are often the first treatment against the fungus, and if resistance grows as the germ evolves, C. auris could become extremely difficult to treat. 

C. auris was first reported in the United States in 2016 and public health officials hoped that it could be contained (primarily in Illinois and New York) through intensive screening and infection control in healthcare settings.

Now, C. auris can now be found in half of the 50 states, with higher concentrations in California, Texas, Florida, and Nevada. The strain on healthcare systems due to the COVID-19 pandemic may have also worsened the spread of the fungus.

According to the CDC, case counts may have increased due to enhanced screening efforts, including colonization screening. This is a test to see if a patient has the fungus somewhere inside of their body, but does not have the symptoms of infection. Symptoms include chills and fever that intensify without treatment, which are common to other fungal infections

While scientists believe that C. auris is not a threat to those with immune systems that can fight it off, it poses a danger to medically fragile individuals, including patients on ventilators, cancer patients on chemotherapy, and nursing home patients. It forms in medical equipment and is estimated to be fatal in between 30 to 70 percent of hospitalized people who develop bloodstream infections.

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Robust cleaning of medical supplies and screening will be needed to help stop the spread since it tends to cling to protective gear like nursing gowns and gloves. These items should be changed frequently, but were reused due to supply shortages brought on by the pandemic. It can also attach to medical equipment like ventilators.

“If [the fungi] get into a hospital, they are very difficult to control and get out.” William Schaffner, a professor of medicine in the infectious diseases division of Vanderbilt University Medical Center, told The Washington Post,“They can persist, smoldering, causing infections for a considerable period of time despite the best efforts of the infection control team and everyone else in the hospital.”

However, it’s not a hopeless situation, Lyman told The New York Times. She cited intensive efforts by Illinois and New York to stop the spread that appear to be effective within health care settings.