The Centers for Disease Control and Prevention (CDC) warned on Monday that a deadly fungus called Candida auris (C. auris) is spreading at an “alarming rate” in U.S. hospitals.

In a press release, Dr. Meghan Lyman, an epidemiologist at the CDC and the paper’s lead author, said that the rapid increase and geographic spread of cases are worrying and show the need for continued surveillance, more lab space, faster diagnostic tests, and sticking to methods that have been shown to prevent and control infections.

The number of C. auris infections resistant to echinocandins, the antifungal medicine most commonly used to treat these infections, tripled by 2021. This increased the agency’s concern.

The CDC called C. auris an “urgent antimicrobial resistance (AR) threat.” This means that it is often resistant to multiple antifungal drugs, spreads easily in hospitals, and can cause serious infections with high death rates.

Since the first case of C. auris was reported in 2016, there have been a total of 3,270 clinical cases and 7,413 screening cases.

The agency said that the spread is due to “poor general infection prevention and control (IPC) practices in healthcare facilities.” But the increase in reported cases is also due to more people trying to find them.