Nearly three dozen people in the United States have been diagnosed with a deadly and highly drug-resistant fungal infection since federal health officials first warned U.S. clinicians last June to be on the lookout for the emerging pathogen that has been spreading around the world.
The fungus, a strain of a kind of yeast known as Candida auris, has been reported in a dozen countries on five continents starting in 2009, where it was first found in an ear infection in a patient in Japan. Since then, the fungus has been reported in Colombia, India, Israel, Kenya, Kuwait, Pakistan, South Korea, Venezuela and the United Kingdom.
Unlike garden variety yeast infections, this one causes serious bloodstream infections, spreads easily from person to person in health-care settings, and survives for months on skin and for weeks on bed rails, chairs and other hospital equipment. Some strains are resistant to all three major classes of antifungal drugs. Based on information from a limited number of patients, up to 60 percent of people with these infection have died. Many of them also had other serious underlying illnesses.
Those at greatest risk are individuals who have been in intensive care for a long time or who are on ventilators or have central line catheters inserted into a large vein.
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In the United States, the largest number of infections has been reported in New York, with at least 28 cases, according to the Centers for Disease Control and Prevention. Infections have also been reported in Illinois, Maryland, Massachusetts and New Jersey. Last June, the CDC sent an urgent alert to clinicians to start looking for the infections, which are difficult to identify with standard laboratory methods.
"As soon as we put out that alert, we started to get information about cases and now we know more about how it spreads and how it's acting," Tom Chiller, the CDC's top fungal expert, said in an interview Thursday. The CDC now tracks the number of infections, updating the case count every few weeks.
In addition to the 35 infected patients, an additional 18 were carrying the organism but weren't sickened by it.
The microbe is among a group of newly emerging drug-resistant threats, health officials said.
"These pathogens are increasing, they're new, they're scary and they're very difficult to combat," said Anne Schuchat, CDC's acting director, during a briefing in Washington this week about growing antimicrobial resistance.
Of the first seven cases that were reported to the CDC last fall, four patients had bloodstream infections and died during the weeks to months after the pathogen was identified. Officials said they couldn't be sure whether the deaths were caused by the infection because all the individuals had other serious medical conditions. Five patients had the fungus initially isolated from blood, one from urine, and one from the ear.
The infection is still relatively rare. "It's really hitting the sickest of the sick," Chiller said.
So far, the fungus doesn't seem to be evolving into new strains within the United States. Because the country doesn't yet have any "homegrown" strains of the deadly fungus, "it gives us a better opportunity to contain it and stop it from spreading," Chiller said.
In other countries, infections have been resistant to all three major types of antifungal drugs, but so far the U.S. cases have been treatable with existing drugs.
Because invasive bloodstream infections with Candida are common in hospitalized patients in the United States, health officials are concerned that this deadly strain could "get into that mix," Chiller said. Unlike Candida infections in the mouth, throat or vagina (which are typically called yeast infections), invasive yeast infections can affect the blood, heart, brain, eyes, bones and other parts of the body and are more dangerous.
Among infectious disease clinicians and laboratory personnel, infections involving fungi don't typically ring the same kind of alarm bells as antibiotic-resistant bacteria - until now.
"This is a paradigm shift, because Candida is not generally thought of as highly resistant or passed person to person," he said.
Since the CDC issued its alert in June, the agency has provided funds and additional expertise to help regional laboratories and hospitals identify the organism.