Drug-resistant fungus is spreading at an 'alarming rate' in the US, CDC says

• Candida auris is a fungus that hit the US in 2016 and has evolved resistance to many common drugs.
• While C. auris is not usually a threat to healthy people, it can be deadly to sick people.

Compared to the deadly fungal outbreak of mutated Cordyceps in "The Last of Us," the current fungal threat in the US may seem relatively benign. But according to the US Centers for Disease Control and Prevention, we also have a fungus spreading through the country at an "alarming rate."

The fungus, Candida auris, won't turn you into a zombie or a "clicker" like in the popular TV show. In fact, for most healthy people, a brush with Candida won't end in illness.

But C. auris poses a growing threat to sick people in healthcare facilities, and according to the latest update from the CDC, it appears to be evolving new levels of drug resistance as it spreads across the US.

A growing portion of C. auris infections have not responded to treatment with the top-recommended antifungal, a medicine called echinocandins. According to the CDC, the number of drug-resistant C. auris cases recorded in the US tripled from 2020 to 2021.

The CDC's findings suggest that the fungus thrived during the COVID-19 pandemic, spreading throughout critical care settings as hospitals were overwhelmed by COVID cases.

Candida cases tripled in 2021

C. auris first infected the US in 2016. At the time, hospitals and nursing homes in New York and Illinois were hit the hardest. A select few cases were classified as pan-resistant, meaning they did not respond to treatment with all three common types of antifungal drugs.

By the end of 2021, the fungus spread to half of the 50 states. A total of 3,270 clinical cases, where the fungus caused an infection requiring treatment, have been recorded in the US since 2016, according to the CDC. A huge portion — 1,474 of those cases — were recorded in 2021.

Case counts for C. auris have continued to rise in 2022, and the fungus has hit California, Nevada, and Florida the hardest. According to CDC surveillance data, the states each had about 350 clinical cases or more in that year alone.

Public health officials have gotten into the habit of screening for C. auris in healthcare settings, so they're getting better at catching the fungus before it infects patients with compromised immune systems. These screening cases, where the fungus is detected but does not cause an infection, tripled from 2020 to 2021.

The fungus poses a deadly threat to the sickest patients

The most common symptoms of C. auris infection are fever and chills. Since most people who get symptomatic C. auris infections are already sick, it can be difficult to tell the infection apart from other underlying causes, leading to delays in getting the right treatment.

Only a specialized laboratory test can diagnose C. auris infection with certainty, as it can be easily confused with other types of yeast, the CDC said.

People who have breathing tubes, feeding tubes, and catheters seem to have the highest risk of infection with C. auris, according to the CDC. Other risk factors for infection include recent surgery, diabetes, and broad-spectrum antibiotic or antifungal use.

While most C. auris infections are curable with antifungal drugs, the fungus' evolving resistance makes it more difficult to treat. Based on information from a limited number of patients, the CDC estimates that 30–60% of people with C. auris infections have died. However, many of them had serious co-infections that increased their risk of death.

As Candida risks infecting more sick people, the CDC is working with regional health departments to track the emerging threat of antifungal resistance.