Thirteen cases of a sometimes deadly and often drug-resistant fungal infection, Candida auris, have been reported in the United States for the first time, health officials said Friday.
The infection, which often spreads in hospitals and other health care settings, can invade the ear canal, urine and bloodstream.
Four of the US patients diagnosed with the infection have died, although the precise causes remain unclear, the CDC said.
"We need to act now to better understand, contain and stop the spread of this drug-resistant fungus," the US Centers for Disease Control and Prevention (CDC) Director Tom Frieden said.
"This is an emerging threat and we need to protect vulnerable patients and others."
The CDC first identified the fungus as an emerging global threat in June 2016.
It was first described in 2009 after being isolated from external ear canal fluids from a patient in Japan, and has since been reported in Britain, Colombia, India, Israel, Kenya, Kuwait, Pakistan, South Africa, South Korea and Venezuela.
The report in the CDC's Morbidity and Mortality Weekly Report (MMWR) described seven of the US cases, which occurred between May 2013 and August 2016.
Another six "were identified after the period covered by the report and are still under investigation," it said.
The first seven cases were reported in New York, Illinois, Maryland and New Jersey.
"All of the patients had serious underlying medical conditions and had been hospitalized an average of 18 days when C. auris was identified," the report said.
Of the four who died, "it is unclear whether the deaths were associated with C. auris infection or underlying health conditions."
A total of 71 percent of the C. auris strains from US patients "showed some drug resistance, making treatment more difficult," the CDC report added.
"Samples of C. auris strains from other countries have been found to be resistant to all three major classes of antifungal medications."
Although lab tests showed the US strains were related to strains from South Asia and South America, none of the patients had traveled to or had any direct links to those regions.
The health authorities believe the US infections were acquired locally.
"It appears that C. auris arrived in the United States only in the past few years," said Tom Chiller, chief of 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."
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