In one of the most remote corners of the earth, a drug-resistant super-fungus has been discovered that can make millions of people sick.
Thousands of feet above sea level in a mountainous region of southwestern China, Canadian researchers identified a common type of fungus that had evolved to become resistant to common drugs used to treat fungal infections.
Fungi can become resistant to treatment after prolonged exposure to antifungal agents or fungicides used for agricultural practices, although the samples collected in China were far from agricultural lands where fungicides are more common.
A rapidly spreading, treatment-resistant fungus could spell disaster for the healthcare system still reeling from the damage done by three years of dealing with a never-before-seen pathogen.
As treatment-resistant fungi become more common, experts worry that the source of the next global pandemic could be a fungal infection.
The fact that the fungal samples collected from more remote areas of the valley showed the same level of antifungal resistance as the samples taken from areas where fungicides are used more frequently indicates that a greater spread of harder-to-treat fungi is likely to occur
Lead researcher Jianping Xu, of McMaster University in Ontario, Canada, discovered the drug-resistant strain of Aspergillus fumigatus in the Three Parallel Rivers region of southern China, nestled in the eastern Himalayas.
The type of fungus, Aspergillus fumigatus, is a common fungus that so readily releases spores into the air called conidia that people unknowingly inhale hundreds of them a day without getting sick.
But the discovery of a thriving, drug-resistant variant of A. fumigatus in the remote reaches of the Himalayas could pose a danger to humans, said Dr Xu, whose work also covers pandemic preparedness.
Treatment-resistant fungal infections may seem more in line with a science fiction drama on premium cable than a possibility to be reckoned with, but the burden of these pathogens is already being felt nationwide.
Fungal infections caused by Candida auris are becoming more common in the US and Europe. The number of infections even increased more than eightfold in the US from 2017 to 2021, from 171 annual cases to 1,420. The mortality rate for C. auris infection ranges from 30 to 60 percent.
The team from McMaster University headed to the remote Three Parallel Rivers region of Yunnan, China, a unique geographic area nestled amid glacial peaks and mountains that span more than 4.2 million acres.
They sampled 331 strains of A. fumigatus in nearly 2,000 soil samples in the Three Parallel Rivers region and found that nearly seven percent of them were resistant to common antifungal infection treatments itraconazole and voriconazole.
Dr. Xu said, ?Seven percent may seem like a small number, but these drug-resistant strains are able to spread very quickly and take over local and regional populations of this species.
“There is a need for increased surveillance of environmental drug resistance in different geographic regions.”
The findings were published in the journal mSphere.
Some 4.8 million people worldwide have a type of lung disease that stems from an allergy to Aspergillus.
Most varieties of the aspergillus genus are harmless, but inhaling A. fumigatus spores can lead to severe aspergillosis infection in immunocompromised individuals or those with underlying lung disease. An estimated three to four million people worldwide become ill with aspergillosis each year.
Dr. Xu said, ?This fungus is very ubiquitous ? it is around us all the time. It is estimated that we all inhale hundreds of spores of this species every day.
“It can be very dangerous – it can lead to lung removal or even death – and now more and more of these infections will be affected by drug resistance.”
The fact that the fungal samples collected from more remote areas of the valley showed the same level of antifungal resistance as the samples taken from areas where fungicides are used more frequently indicates that a greater spread of harder-to-treat fungi is likely to occur .
The study’s authors pointed out that drug-resistant fungi can easily spread from agricultural fields to non-agricultural areas through human influences such as travel and trade, as well as weather and runoff.
The outlook for Aspergillus is murky, because the Centers for Disease Control and Prevention doesn’t track it in the same way. But it is estimated to cause severe aspergillus infections approximately 14,000 hospital admissions annual.
Unlike Candida auris, which is mainly found in hospitals, people can contract treatment-resistant aspergillus from their home flower beds.
An April 2022 study published in the journal Nature microbiology tested this by collecting lung samples from infected people in the UK and Ireland and matching some of them to drug-resistant strains in nearby environments.