Drug-Resistant, Pathogenic Yeasts Can Thrive on the Surface of Apples, Other Fruits

When apples and other fruits are prepared for travel, they are frequently treated with a fungicide to prevent spoiling and improve shelf life.

The method retains freshness, but it may be a double-edged sword: it may aid in the selection and spread of pathogenic yeasts that are multi-drug resistant.

New research published this week in mBio, an open-access publication of the American Society for Microbiology, adds to that theory.

Human pathogen caused by fungicide

(Photo : AHMAD SAHEL ARMAN/AFP via Getty Images))

Earlier research has concerned with the human pathogen Aspergillus fumigatus, according to mycologist Anuradha Chowdhary, M.D., Ph.D., at the University of Delhi, but the new study focuses on drug-resistant cell lines of Candida Auris, a pathogenic yeast secluded from the environment that spreads quickly in hospitals, as per ScienceDaily.

Fungicides used in agriculture may accidentally select drug-resistant fungi, according to Chowdhary.

She and her colleagues looked for pathogenic C. auris and other yeasts on the surfaces of 84 fruits from nine distinct tree fruit species.

The fruits were obtained in northern India in 2020 and 2021 and contained 62 apples (20 harvested in orchards and 42 purchased from a store in Delhi). At least one form of yeast was found in each fruit species.

Many medications are resistant to C auris. It was initially discovered in Japan in 2009, and it has since spread to all inhabited continents.

Researchers have been looking at how the disease develops and spreads.

"We still don't fully grasp the mechanisms that cause the simultaneous formation of numerous separate C auris genetic clusters," Xu added.

Chowdhary and Xu's work, published last year in mBio, was the first to isolate C auris from a natural setting, the marshes and sandy beaches of an Andaman Islands coastal ecosystem in India.

According to the latest results, apples may act as a selection force for the disease and aid in its spread.

Even though the study only looked at fruits from northern India, Xu pointed out that the spread of C. Auris is not a uniquely Indian phenomena.

It's a worldwide threat: the Centers for Disease Control and Prevention designated C. auris as one of five diseases that represent an immediate danger to public health across the world.

To determine how to respond to the pathogen's threat to people, researchers must first understand how it moves through other natural systems.

Effects of agricultural fungicides to people

Modern fungicides sprayed on fruits and vegetables have come under renewed attention after scientists discovered that they triggered comparable genetic abnormalities in mouse neurons to those seen in autism and Alzheimer's disease, as per The Guardian.

Researchers subjected dishes of brain cells to over 300 different pesticides and fungicides and discovered that one family of fungicides, strobilurins, caused patterns of genetic modifications similar to those seen in human situations.

Scientists at the University of North Carolina in Chapel Hill thought that the experiment would offer light on the types of environmental chemicals that contribute to autism cases.

Surprisingly, they discovered substances that produced several genetic markers for autism as well as neurodegenerative disorders at the same time.

The strobilurins have just been licensed for usage in the last 20 years, more than half a century after the first person diagnosed with autism was revealed in the medical literature.

Since their introduction to the market, fungicides have been applied in greater quantities to preserve crops such as cabbages, spinach, lettuce, kale, tomatoes, apples, pears, and grapes.

While the fungicides generated autism- and Alzheimer's-like fingerprints in the way genes are expressed in mouse brains, the significance of the alterations is unclear: the researchers have no proof that the chemicals contribute to either disorder.