A deadly new drug-resistant fungus has been linked to the deaths of four hospital patients in the U.S., according to a report released Friday from the Centers for Disease Control and Prevention.

The fungus, called Candida auris, preys on the sickest patients and can spread in hospitals. Although doctors have been concerned about the spread of antibiotic-resistant bugs for many years, this fungus is relatively new on the world scene. It was first identified in Japan in 2009 and has since spread around the globe, emerging in South America, the Middle East, Africa and Europe, according to the CDC.

The CDC first identified the fungus as a potential threat in 2013, based on a possible case in the U.S., and has been on the lookout for the fungus since June. In its new report, the CDC said the fungus has been detected in a total of 13 patients since May 2013; the agency provided details on the first seven cases, which were reported in New York, Illinois, Maryland and New Jersey.

All of the patients had serious underlying medical conditions, including cancer, and had been hospitalized an average of 18 days when they tested positive for the fungus. Two patients had been treated in the same health care facility and had nearly identical fungal strains. Doctors can’t say for sure if the patients died from the fungus or their underlying health problems.

But health officials say the nation’s hospitals need to be on alert.

“We need to act now to better understand, contain and stop the spread of this drug-resistant fungus,” said Thomas Frieden, director of the CDC. “This is an emerging threat, and we need to protect vulnerable patients and others.”

Identifying the fungus is difficult and requires special laboratory methods because it’s so similar to other bugs. Most of the samples in the new report were initially misidentified as other fungal species, the CDC said.

Treating the fungus is even harder; 71 percent of the fungal samples were resistant to current drugs. Samples of the fungus in other countries have been resistant to all three major classes of antifungal drugs.

Hospitalized patients are at especially high risk from the fungus because many have had antibiotics, which can kill off healthy bacteria that help protect us from disease, said Peter Hotez, dean of the National School of Tropical Medicine at Baylor College of Medicine in Houston.

“It’s a warning or wake-up against the indiscriminate use of antibiotics, especially in hospital settings,” Hotez said.

Hospitals have been testing for the fungus more frequently due to outbreaks in Asia and the United Kingdom, said Amesh Adalja, senior associate at the UPMC Center for Health Security in Baltimore.

In earlier outbreaks, the fungus has killed 59 percent of patients, including 68 percent of patients whose infection spread to the bloodstream, said Adalja, who published a brief report on the infection Friday. Previous patients have had a median age of 54, Adalja said. The most common underlying medical problem was diabetes, and half of the patients had undergone surgery within 90 days. Nearly 80 percent of patients had a catheter placed in a major vein in the chest and 61 percent had a urinary catheter.

“Candida auris is a major threat that carries a high mortality,” Adalja said. “Candida fungal species are ubiquitous.  …  As we learn more about this species, it will be essential to understand how it spreads in health care facilities and what the best infection control and treatment strategies are.”

Although it’s unclear exactly how the patients were infected, the CDC said that the fungus strains were related to ones found in South Asia and South America. None of the patients had traveled to those regions, however, and likely caught the infections here in the U.S.

The fungus apparently “arrived in the United States only in the past few years,” said Tom Chiller, chief of the CDC’s mycotic diseases branch. “We’re working hard with partners to better understand this fungus and how it spreads so we can improve infection control recommendations and help protect people.”

Hospitals should thoroughly clean rooms where patients with the fungus has stayed, the CDC said.

This article originally appeared on Kaiser Health News, a national health policy news service that is part of the nonpartisan Henry J. Kaiser Family Foundation.  

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