A potentially deadly yeast pathogen is fueled by some antifungal chemicals used on fruits while they are being grown.
Discovered in 2009, C. auris can be incredibly dangerous to immunocompromised people who come into contact with it.
While the fungus does not harm the majority of people who come into contact with it, those who develop a fungal infection have few treatment options as some cases are resistant to all known drugs.
The fungus was recently found in fruit grown or sold in India in 2020 and 2021 when the infection reemerged.
Researchers from India warn that applying antifungal drugs to fruit, particularly apples, could cause the growth of a potentially dangerous fungal infection called C. auris. Pictured: A man sprays an apple orchard with pesticides in Srinagar, Kashmir, India
Researchers from the University of New Delhi conducted an experiment published in mBio last month in which they examined the surface of 84 fruits for the infectious fungus.
Of the fruits used in the study, 62 were apples, and the fruits came either from orchards in the New Delhi region or from markets in the country’s capital.
Researchers found that each of the fruits was the host of at least one species of yeast.
Eight of the apples included in the study, or 13 percent, were found to have strains of the C. auris fungus that are resistant to common antifungal drugs.
All had been placed in some form of storage between purchasing the pick from the orchard and conducting the study.
They believe the antifungal treatments used on apples grown on commercial orchards help these resistant fungi grow.
Like other pathogens, these fungi evolve over time and through these evolutions build resistance to treatments.
Since these fruits are doused in anti-fungal treatments, almost all of the pathogen is killed.
However, the small pieces that remain will begin to mutate in ways that will help her survive the anti-fungal chemicals.
In doing so, it also begins to take on properties that make it more likely to survive known treatments for infections that are available to humans.
“High levels of antifungal resistance are common in these environmental isolates of apples,” the researchers wrote.
“The results expand our understanding of the ecology of C. auris and should help develop a better strategy to minimize the spread of this multidrug-resistant fungal pathogen.”
Although C. auris is known to form on apples produced in India, researchers fear that it is present on fruit around the world and that collecting data on the pathogen is currently impossible (file photo).
While none of the fruits in the Indian study contained C. auris, researchers write that the presence of other fungi raises the possibility and that their findings are not at all shocking.
The successful isolation of C. auris from apple surfaces is not surprising,” the researchers wrote.
“Yeasts are widespread from an ecological point of view. Candida auris belongs to the Metschnikowiaceae family, a group of yeasts isolated primarily from non-human sources such as plants (both living and dead) and marine environments.
“Previous studies have shown that several, including Metschnikowia pulcherrima, Metschnikowia sinensis, and Metschnikowia fructicola … are commonly associated with fruit.”
The exact spread of the fungal virus among fruits is difficult to determine because it is so widespread, and likely in so many places, that experts don’t currently have the tools to track it closely.
However, this is a serious concern for infectious disease experts. The Centers for Disease Control and Prevention consider C. auris a pathogen that poses an urgent public health threat.
The inability to collect and properly track data on the number of people infected makes it nearly impossible to conduct surveillance.
A majority of those infected also feel no symptoms, which is good on the one hand, but it also means that people can carry a dangerous disease without even knowing it.