PhD student studies fungus that makes vulnerable people life-threateningly ill
In recent years, the fungus Candida auris spread rapidly in hospitals around the world. UvA PhD student and molecular biologist Auke de Jong investigated how the fungus spreads and makes vulnerable people life-threateningly ill. “I discovered that the problem is actually much bigger than Candida auris alone.”
After a coronavirus pandemic, should we now be preparing for a fungus pandemic?
“Fungi are increasingly causing problems, with the caveat that fungi are not as dangerous as viruses: they do not directly infect healthy individuals. Fungi are opportunistic: they live everywhere on and around us, and when your immune system weakens you can get sick from them. Every year, 1.6 million people worldwide die from fungal infections, and that number is growing.”
Why this growth?
“First, the group of susceptible people is increasing. These are people with weakened immune systems, such as leukemia or AIDS patients. But also premature infants, people with transplant organs and the elderly. In addition, globalization and climate change have increased the range of fungi. Fungi that used to be found only in the tropics are increasingly appearing in countries with temperate climates because it is getting warmer there, too. Also, trade and tourism are spreading fungi around the world.”
You did research on the Candida auris fungus that has been popping up in hospitals in recent years. Why specifically that fungus?
“There has been a kind of ‘hype’ around Candida auris in recent years, because the fungus turned up in hospitals all over the world and proved resistant to all available drugs. Ten years ago, the fungus was first discovered in an ear, where it caused an infection. The first Candida auris variant was treatable, but within a few years variants appeared that were resistant to one or more antifungals. Meanwhile, the fungus is resistant to all drugs. I wanted to chart: how does this fungus work? How does it spread and how does it make people sick?”
And?
“One of the discoveries I made in my dissertation is that related fungal species of Candida auris also have high resistance to antifungal drugs, which means that the story of Candida auris is not unique but that many more such fungi are spreading. So the problem is in fact much bigger than Candida auris alone.”
How worrisome is that?
“I do not want to exaggerate, Candida auris is not corona or ebola, but I do find the growing group of susceptible patients and the rise of resistant fungi worrying. With fungi, the same thing is happening now as with antibiotic resistance. Fungi are becoming increasingly resistant because of the widespread use of antifungal drugs, for example, in agriculture for plants and animals. As a result, people with fungal infections in the hospital can no longer be treated properly either.”
How do you get infected by the fungus Candida auris?
“One theory is that people already carry the fungus on their skin when they enter the hospital and that the fungus enters the body during surgery. The fungus then enters your bloodstream, starts growing there and results in a blood infection. These kinds of infections are life-threatening and if not recognized and treated in time, patients can die within days.
So far, all studies indicate that the fungus can only be transmitted from skin to skin, i.e. not via aerosols in the air. However, an object can transmit the fungus. For example, in a hospital in England an entire ward was infected by Candida auris transmitted by a contaminated ear thermometer.”
How do people initially come into contact with the fungus?
“That remains a mystery for now. So far, studies have not shown that the fungus is part of our own microbiome, so we would have to contract it somewhere. But where exactly remains to be seen. What I think is the most logical hypothesis is that the fungus would grow in seawater. After all, Candida auris can withstand high salinity and other extreme conditions very well. Related species have also been found on coral and fish. Ear infections reinforce the sea hypothesis because water gets into your ear when you swim. But conspecifics of the fungus do not just show up in coastal sites; they have also been found on tropical plants in the jungle. We would have to take many more samples to find an original source.”
What can you do against a fungus yourself?
“As a person, there is not much you can do, fungi are all around us and that is a good thing, because they are essential for all life on earth. But hospitals could develop better diagnostics to screen patients preventively for fungi.”
Auke de Jong hopes to receive his doctorate on Friday, December 22 at 4 p.m. for his dissertation Fungal Pathogens Exposed. Novel insights into Candida auris and emerging relatives of the Candida haemulonii species complex. The defense will take place in the Agnietenkapel and is free to attend.
