A deadly, drug-resistant fungus has been rapidly spreading in recent years at U.S. health care facilities, the Centers for Disease Control and Prevention said Monday.

Infections from the yeast strain Candida auris, or C. auris, have jumped from 476 in 2019 to 1,471 in 2021, while screening cases — those in which the fungus is detected but there is no infection — tripled from 2020 to 2021 to 4,041, according to a CDC study published in the Annals of Internal Medicine.

The number of cases resistant to echinocandins, the antifungal medicine most commonly recommended to treat C. auris infections, also tripled from 2020 to 2021. 

The CDC has declared the fungus an urgent antimicrobial resistance threat because it is often resistant to multiple drugs, spreads easily in health care facilities and can cause severe infections with high death rates. 

The fungus is not considered a threat to healthy people, but those who are very sick, have invasive medical devices — such as ventilators or central venous catheters — or have long or frequent stays in health care facilities are at an increased risk. 

In some patients, the yeast can enter the bloodstream and spread throughout the body, causing severe infections. The CDC says 30% to 60% of people with C. auris infections have died, although many had other serious illnesses that could have contributed to their deaths.

The fungus was first reported in the U.S. in 2016. Cases have increased each year since, and 2022 is on pace for another record high, the CDC said. The fungus has been detected in 28 states.

“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,” CDC epidemiologist Dr. Meghan Lyman, lead author of the paper, said in a statement.

The CDC said the rise in C. auris cases may be a result of poor infection prevention and control practices at health care facilities as well as increased testing. The agency said the findings also suggest the strain on health care systems during the COVID-19 pandemic might have exacerbated the fungus’ spread.

The CDC said it’s important to quickly identify C. auris in a hospitalized patient so that facilities can take steps to contain the fungus. 

The agency said it has increased laboratory testing capacity, including at state and local health departments. The CDC is also working with state and local health officials and other to address what it calls an “emerging threat to public health.”