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Candida auris is a newly discovered fungus that is baffling scientists. Getty Images

A deadly fungus that’s resistant to commonly used antifungal medications is spreading in healthcare facilities around the world.

Already, hundreds of infections have been reported in the United States, and the Centers for Disease Control and Prevention (CDC) has called this a “global emerging threat.”

Here’s everything you need to know about this potentially deadly drug-resistant fungus.

C. auris is a type of fungus that can cause a serious infection in people with a weakened immune system, often in those hospitalized for other medical reasons.

This fungus was first identified in 2009 in Japan. Since then, infections with C. auris have been reported in over 20 countries, including the United States.

As of the end of February, 12 U.S. states have confirmed infections, including New York, New Jersey, and Illinois.

C. auris is concerning for several reasons, said Mahmoud Ghannoum, PhD, MBA, a professor and director of the Center for Medical Mycology at Case Western Reserve University and University Hospitals Cleveland Medical Center.

“With this species, we are starting to see that it is not only resistant to one drug,” said Ghannoum. “It can also be resistant to two drugs, and sometimes we have some isolates that are resistant to all antifungals that are available on the market.”

Like drug-resistant bacteria before them, fungi are evolving ways to survive drugs commonly used to treat infections.

A CDC review of 51 C. auris infections that occurred in healthcare facilities in New York City from 2016 to 2018 found 98 percent of C. auris samples were resistant to one of the commonly used antifungal drugs.

Ghannoum said C. auris is also able to adapt to different environments. In hospitals, it can be found on benches, beds, medical equipment, and other surfaces.

The fungus is so persistent that hospitals sometimes have to close down an entire ward and use special cleaning equipment to get rid of it.

Any infection can be serious and fatal, especially if it’s difficult to treat and a person has a compromised immune system.

C. auris can cause many different types of infections, including in wounds, the bloodstream, and ears.

The fungus has also been found in the respiratory tract and urine samples, although it’s unknown whether it causes infections in those areas of the body.

The CDC reports that 30 to 60 percent of people with C. auris infections have died. However, this is based on a small number of cases.

It’s difficult for doctors to point to C. auris as the main cause of death because many of these patients had other medical conditions that may have contributed to their death.

Ghannoum said people with weakened immune systems are prime targets for C. auris, especially those exposed to the fungus in healthcare settings.

“Risk factors for C. auris infection include frequent or prolonged hospitalizations and residence in skilled nursing facilities,” said Dr. Bernard Camins, medical director for infection prevention at Mount Sinai Health System. “Other risk factors are diabetes, previous surgery, and exposure to multiple antibiotics and antifungals.”

This includes people who have a central venous catheter, endotracheal tube, or urinary catheter entering their body.

Camins said people who are in good health aren’t at risk for developing C. auris infections.

However, the fungus can colonize their skin. Ghannoum said it can even be found on the skin of people who’ve been successfully treated with antifungals.

“When it is on the skin, it is possible for a person to infect other people with it,” he said.

Camins said the majority of C. auris isolates in the United States are resistant to at least one of three major classes of antifungals.

Some are resistant to two. And some to all three.

“Fortunately,” said Camins, “C. auris isolates that are resistant to all three classes of antifungals are not commonly reported.”

One type of drug, the echinocandins, is still effective against 95 percent of C. auris isolates, reports the CDC, although this may change over time.

Infections caused by resistant C. auris are more difficult to treat. Sometimes, they can only be treated with high doses of multiple types of antifungals.

Although C. auris affects mainly people with compromised immune systems, Camins said, “Everyone should be concerned about the emergence of multidrug-resistant pathogens.”

Researchers at the Washington University School of Medicine estimate that 162,000 people died in 2010 as a result of multidrug-resistant organisms.

Camins said the increase in resistant organisms is fueled by overuse of antimicrobial drugs, not just in healthcare settings but also in agriculture.

As more microorganisms evolve ways to survive commonly used drugs, treating infections becomes more difficult. This increases the risks associated with hospitalizations and surgeries.

Scientists are already testing other compounds to see if they can work as antifungals against C. auris, including in a mouse study published in 2017 by Ghannoum and his colleagues.

“We tested new antifungals, which are under development now,” he said. “They seem to have very good activity against this organism.”

If effective in animals, these potential drugs would still need to be tested in clinical trials in people before they could be used in the hospital. That could take several years.

This research should be helped along by additional support from the federal government.

“The NIH has now started to provide funding to do studies,” said Ghannoum. “And the awareness that the CDC is raising is going to really help contain this organism.”