Deadly, drug-resistant yeast infection is spreading around the world

This emerging strain of yeast, known as Candida auris, causes bloodstream, wound and ear infections. Photo / iStock

US health officials are warning hundreds of thousands of clinicians in hospitals around the country to be on the lookout for an emerging and highly drug-resistant type of yeast that is causing potentially fatal infections in hospitalised patients around the world.

Most people are familiar with the garden variety kind of yeast infections that people get on the skin or in their genitals. But invasive yeast infections can be fatal, especially for patients in intensive care or having surgery. Others at risk include people with diabetes, patients taking powerful antibiotics and antifungal medications, and those with catheters.

This emerging strain of yeast, known as Candida auris, has triggered outbreaks in health-care settings, causing bloodstream, wound and ear infections. Since 2009, the pathogen has been found in nine countries on four continents, including one possible infection in the United States in 2013.

The Centers for Disease Control and Prevention sent a clinical alert late last week to U.S. health-care facilities and dozens of medical societies to share with their members.

"CDC is concerned that C. auris will emerge in new locations, including the United States," the alert said. The infections have most commonly been acquired in hospitals and occurred several weeks into a patient's hospital stay.

Officials warn that the yeast doesn't respond to common antifungal drugs and is difficult to identify with standard laboratory methods.

"What concerned us is that it is potentially resistant to one or two, if not all three" main classes of antifungal drugs used to treat these infections, said Tom Chiller, the CDC's top fungus expert, in an interview yesterday.

Invasive infections with any type of Candida can be fatal. Based on information from a limited number of patients, 60 per cent of people with this new type of Candida infection have died, but it's not clear how many of them had other serious illnesses that also increased their risk of death.

Most hospital labs in the United States also don't have the capacity to identify the new strain because it can be confused with other more common types of yeast. As a result, misidentification could lead to inappropriate treatment, he said.

That's particularly important with this organism because the limited data so far suggests that the infections have occurred primarily in patients who were already in the hospital for other reasons. Unlike other types of yeast that typically spread from person to person, "this one seems to get into hospital settings and stay there," Chiller said, and may spread from contact with the environment, such as contaminated surfaces or equipment.

The organism was first identified in 2009 in Japan from a patient's external ear discharge. Infections have also occurred in South Korea, India, South Africa, Kuwait, Pakistan, Colombia, Venezuela and the United Kingdom. Because identification requires specialized laboratory methods, the CDC alert said infections likely occurred in other countries but have not been identified or reported.

Based on a review of specimens collected in the past, CDC officials said they are aware of one possible infection in the United States in 2013 that was collected by a private lab. The CDC has tested a small sample of Candida specimens over the last eight years, and so far the deadly new yeast has not turned up. But the testing is limited, he said - there's surveillance at only four sites in the country, and only about 7,000 samples have been analysed.

The CDC is recommending that hospitals and other health-care facilities that suspect they have a patient with such an infection contact local public health authorises and the CDC. They also recommend that patients carrying or infected with this organism have their own rooms, and that their rooms are thoroughly cleaned and disinfected every day with an EPA-registered, hospital-grade disinfectant that targets fungus.