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C. auris, isolated in Japan a decade ago, now on global list of superbugs

A computer illustration of the Candida auris fungus.

A computer illustration of the Candida auris fungus. C. auris was first identified in 2009. It causes serious multidrug-resistant infections in hospitalized patients and has high mortality rates.  Credit: Alamy Stock Photo/Science Photo Library / Alamy Stock Photo

Candida auris, a pathogenic fungus that has been spreading throughout the United States, was discovered in Japan a decade ago after its isolation from a patient with an ear infection. 

Shortly afterward, the fungus — which was new to medicine — was identified around the globe. 

It was detected elsewhere in Asia and as far south as Australia. By 2013, it was in Britain, where it spread to 55 hospitals, and by 2017 had infected more than 200 patients, a report in the scientific journal Public Health England revealed.

British doctors remarked about the tenacity of the fungus and the difficulty of removing it from hospital surfaces.

Dr. Tom Chiller, who heads the fungal division at the Centers for Disease Control and Prevention in Atlanta, believes the drug-resistant pathogen emerged in multiple sites simultaneously.

"This bug has a predilection for being resistant," Chiller said. "Most of the isolates we find are resistant right out of the gate. We don't understand why this bug likes to be resistant and is happy being resistant, but it may have something to do with its ability to spread."

Other medical experts see the overuse of human antifungal medications in agriculture and floriculture as potential reasons for resistance in Candida auris, known as C. auris, and possibly other fungi.

Dr. Matt McCarthy, a specialist in infectious diseases at Weill Cornell Medicine in Manhattan, said tulips, signature flowers of the Netherlands, are dosed with the same antifungal medications developed to treat human infections.

"Antifungals are pumped into tulips in Amsterdam to achieve flawless plants," he said. "As a fungal expert, I know that we have very few antifungal medications, and this is a misuse of the drugs."

Studies conducted at Trinity College in Ireland support McCarthy's argument and have demonstrated that tulip and narcissus bulbs from the Netherlands may be vehicles that spread drug-resistant fungi.

Trinity scientists, who examined resistance in another potentially deadly fungus, Aspergillus fumigatus, uncovered why the bugs repelled the drugs known as triazoles. The fungi became resistant because of the overuse of triazoles in floriculture. As with C. auris, drug-resistant A. fumigatus can be deadly in people with poor immunity.

When patients need treatment with triazole-class medications, the drugs don't work because the fungi have been overexposed in the environment, McCarthy said.

He added that the use of antifungal medications in floriculture is similar to the overuse of antibiotics in the poultry and beef industries, which have helped drive resistance to those drugs.

The floriculture example is just one way that drug-resistant fungi can spread around the world. Global trade networks, human travel and the movement of animals and crops are others.

C. auris, studies have revealed, resists antifungals by way of “efflux pumps” that have evolved over time to efficiently force antifungal drugs out as soon as they flow in. The pumps render the fungi impervious to being killed.

Global health experts view C. auris as yet another threat in the rapidly growing number of health care-associated superbugs.

Unless multi-drug-resistant microbes of all kinds are defeated, they will kill more people by 2050 than cancer does now, according to experts at the World Health Organization. The agency has declared drug resistance one of the most pressing medical problems today.

Deaths worldwide from all types of drug-resistant superbugs could rise from the estimated 700,000 now to 10 million in 30 years, WHO researchers estimate, noting that the economic impact could be similar to the 2008 financial crisis because drug-resistant infections are difficult and expensive to treat. A superbug infection can add 30 days to a hospital stay, which inevitably drives up costs.