The Centers for Disease Control and Prevention is tracking an emerging fungus that presents a “serious global health threat.” The CDC said healthcare facilities in 29 states, including Florida, have reported that a type of yeast called Candida auris (C. auris) has been causing severe illness or death in hospitalized patients.

Nevada has reported the most cases, at 384. California has reported 359 cases. Florida has the third most cases, with 349 reported. “In some patients, this yeast can enter the bloodstream and spread throughout the body, causing serious invasive infections,” the CDC said. Researchers said the yeast often does not respond to “commonly used” antifungal drugs, which makes it difficult to treat.

“People who have recently spent time in nursing homes and have lines and tubes that go into their body (such as breathing tubes, feeding tubes and central venous catheters), seem to be at highest risk for C. auris infection,” the CDC said.

An invasive infection with any Candida species can be deadly, according to the CDC. Based on limited information, researchers said more than 30% of patients with C. auris infections have died. However, the CDC said many of these patients had other serious illnesses that increased their risk of death.

The fungus is spread in healthcare settings through contact with contaminated surfaces or equipment, or from person to person. The CDC said it needs to continue to research the fungus to learn more about how it spreads. The CDC said it is alerting healthcare facilities to be on the lookout for the fungus.