A woman in a robe sitting on an examination table.

Health experts continue to be troubled by the increase in the U.S. of Candida auris, a potentially deadly yeast infection that appears to spread more like a bacterial infection than a fungus.

C. auris is "an urgent threat" for several reasons, according to a commentary from Centers for Disease Control and Prevention experts published today in the Annals of Internal Medicine.

"It's highly drug-resistant—the level of resistance is higher than we see for almost any yeast disease in humans," says CDC epidemiologist Snigdha Vallabhaneni, M.D., M.PH., the lead author of the new commentary. "It causes invasive infections, not just something on the skin or a vaginal yeast infection. This has a very high mortality, and it's hard to treat, which is concerning. The most alarming thing is how readily it spreads among a vulnerable population in healthcare settings: hospitals, skilled nursing facilities like those that have patients on ventilators or feeding tubes living on this kind of life support for months or years." 

In some cases, usually in people who are already quite ill, C. auris can cause a widespread, or invasive, bloodstream infection. What’s more, invasive Candida bloodstream infections are becoming increasingly unresponsive to the most commonly used antifungal medications.

As of late May, the CDC says, 685 confirmed cases and another 30 probable cases of C. auris have been reported in the U.S., across 12 states. The majority were in New York, New Jersey, and Illinois, typically in people who were already extremely ill and hospitalized or in long-term care facilities.

While the number of total cases in the U.S. is still small, it’s more than double the 243 from approximately a year earlier. Between 2013 and 2016, there were only 13 known cases in the U.S. (The infection is thought to have first been seen in Japan in 2009 and has since appeared in about 15 countries.)

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Around the world, some 60 percent of people who contracted C. auris have died. In the U.S., the CDC says, more than 30 percent of those with C. auris have died, but it’s unclear whether the deaths were the direct result of the fungal infection or an underlying health problem. Many of the people who have died had serious illnesses.

Compounding the problem is that C. auris can move from one person to another in hospitals, unlike other yeast infections. It can live on contaminated objects such as bed rails, chairs, catheters, and other equipment, and on the hands of healthcare providers.

“C. auris acts more like a type of bacteria called a nosocomial bacteria, which sticks to surfaces, so it can spread from patient to patient or from a healthcare provider to a patient,” says Cornelius Clancy, M.D., director of the mycology program at the University of Pittsburgh School of Medicine. “That makes it hard to get rid of, even in hospitals that have excellent infection-control methods.”

Currently, it’s unclear what’s behind the rise in C. auris. But a changing climate may be contributing, allowing the fungus to thrive in the human body, according to recent research from scientists in the U.S. and the Netherlands, published in mBio, a journal from the American Society for Microbiology. The researchers say C. auris may be the first invasive fungal infections to be able to adapt to temperatures as high as those inside the body, but may not be the last.

It's important to remember this, however: “C. auris is not going to be something that will affect a healthy person, or even a sick person who may be temporarily in the hospital," says Vallabhaneni.

While scientists work to understand more about how C. auris spreads and how best to prevent, diagnose, and treat it, here’s what you need to know if someone you love is at risk.

Who Is at Risk?

If you’re generally healthy, there’s no current cause for concern.

“We haven’t seen [C. auris] in the general community. It’s mainly a hospital-acquired infection,” says Peter Pappas, M.D., a professor of medicine in the division of infectious diseases at the University of Alabama and spokesman for the Infectious Diseases Society of America.

Thus far, this infection, like other invasive yeasts, has struck only “the sickest of the sick—people who are in and out of ICUs and also have central lines or immune-system-lowering conditions such as diabetes,” says Tom Chiller, M.D., chief of the CDC’s mycotic diseases branch and a co-author of the new commentary.

Those at higher risk for C. auris include people in intensive care units for an extended period of time, such as transplant recipients or cancer patients on intravenous antibiotics, as well as those who've been hospitalized often, have already had multidrug-resistant infections, or have been prescribed multiple courses of very broad-spectrum antibiotics.

These antibiotics, notably carpabenems, may change the microbiome of the skin, making it a more hospitable place for the fungus to grow. “We think disruption of the microbiome probably sets up the right environment for C. auris to take over the skin flora,” says Vallabhaneni.   

A prior hospitalization—even overnight—in a country where C. auris has been seen, or being in a skilled nursing facility and having a device like a central line (for medication administration), ventilator, or feeding tube also increases the risk. “All those devices that enter your body put you at risk for all sorts of infections, including Candida auris,” says Vallabhaneni. 

5 Protective Steps

If someone you love or care for is in a hospital, nursing home, or physical rehabilitation facility:

1. Wash your hands well whenever you enter his or her room. “One of the best ways to prevent the spread of dangerous germs like C. auris in healthcare settings is simply good hand hygiene,” Chiller says. The patient should also wash his or her hands regularly and well.

2. Speak up if others aren’t washing their hands correctly. (Healthcare providers do this less than half the time, according to the CDC.) You may need to remind nurses, doctors, and other healthcare professionals to scrub up not only when they come into the room but also after handling a patient’s open wound, blood, or bodily fluids—or even touching his or her skin. Anyone who is wearing medical gloves and removes them should still wash his or her hands.

3. Ask whether any patients in the facility have C. auris. If so, Chiller says, find out whether additional precautionary measures have been put in place. Infected patients should be in a single room, those who come in contact with them should wear gowns and gloves, and healthcare providers should use disposable patient-care equipment for them (such as some blood pressure cuffs) when possible.

4. Make sure the hospital is cleaning properly. There’s no research yet available on the best disinfectant for C. auris, but the CDC recommends the use of an Environmental Protection Agency-registered hospital-grade disinfectant that’s effective against Clostridium difficile spores. These tend to be the strongest disinfectants currently available, Chiller says.

5. If the person is put on IV antibiotics in the ICU, ask whether it’s really necessary. “Antibiotic therapy, specifically IV antibiotics, is a significant risk factor [for any invasive candida], both the number of different antibiotics and the length of therapy,” says David Denning, M.D., a professor of infectious diseases in global health at the University Hospital of South Manchester in the U.K.

6. Make sure doctors are aware of the person's travel history, especially about any healthcare he or she obtained. "People who travel and get healthcare abroad could be at risk for multidrug-resistant organisms like C. auris," says Vallabhaneni. 

Diagnosis and Treatment Challenges

People who develop C. auris are often already very ill, so it may be difficult to distinguish its symptoms from those of other medical conditions.

The most common signs are fever and chills that don’t improve after antibiotic treatment for suspected bacterial infections, Chiller says. If you notice this, bring it to the attention of a health professional on site.

Blood tests are usually used to diagnose invasive candida infections. When C. auris is suspected, hospital staff members should use a special laboratory test with a technology called matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF). 

If the test is positive for the fungal infection, the CDC says that treatment with a class of antifungals known as echocandins is usually effective. In some cases, people may need to be given high doses of several antifungal drugs.

The CDC is aware of a small number of cases in the U.S. that are resistant to all the current antifungal medications. “It’s very uncommon, but we have seen it, and that’s what we’re ultimately concerned about—limited treatment options,” says Vallabhaneni. “That’s why we’re trying to increase awareness, to have clinicians be aware of and help with early detection.”

Early detection, she says, is key. Because C. auris develops resistance quickly, it’s important for anyone with this fungal infection to be monitored to see whether treatment is working and to have follow-up cultures. And because C. auris can live on the skin and other body sites after treatment, continue protective practices—such as ensuring that healthcare workers wear gowns and gloves—until a doctor determines that it’s appropriate to stop them.