Apples may be fuelling the superbug crisis by harbouring drug-resistant strains of a deadly fungus, a study suggests.
Indian and Canadian academics believe fungicides used to keep the fruit fresh are to blame.
Experts found candida auris present on the surface of 13 per cent of apples analysed in Delhi. All of them were stored before purchase — none were freshly picked.
Candida auris was first spotted in 2009 and has since struck hundreds in Britain and the US.
The team admitted they ‘still don’t really understand’ what is driving the fungus. But they speculated fungicides ‘inadvertently select’ the drug-resistant fungi and help it spread.
Indian and US researchers found fungicides used to keep fruit fresh are boosting levels of candida auris (pictured) by improving its survival rate compared to other types of yeasts
Researchers found it was present on the surface of 13 per cent of the apples analysed in the study in Delhi
Multiple cases of C. auris have been reported around the world since the fungus was first discovered in 2009
The study, published in the journal mBio, screened the surfaces of 84 different bits of fruit on sale in northern India.
This included 62 apples — 42 which were picked up in a market in Delhi and 20 that came from orchards.
Results showed candida auris was present on eight apples — five Red Delicious and three Royal Galas.
WHAT IS CANDIDA AURIS?
Candida auris (C auris) is a harmful form of yeast, identified by the CDC as a ‘superbug’ fungus.
It tends to be diagnosed in patients after they’ve been in hospitals for several weeks.
The fungus can infect wounds, ears and the bloodstream and take root in the urinary tract.
The source of the infection for C auris isn’t the person who got sick but rather the hospital environment, including catheters, counters, and other surfaces.
It was first identified in Japan in 2009 and has since spread to more than a dozen countries worldwide.
Two of the three kinds of commonly used antifungal drugs have had little effect in treatment.
About 60 percent of those who’ve been infected with C auris have died.
None of the freshly picked apples had the fungus, according to academics from the universities of Delhi and McMaster.
Being treated with fungicides to increase the fruits’ shelf-life appeared to kill off all types of yeast on the surface of the fruit, apart from candida auris.
The authors claimed this suggested fungicides could be actively helping more resistant fungi thrive.
Drug resistance is caused by pathogens learn to evade the drugs designed to kill them.
Dr Jianping Xu, co-author, said: ‘We still don’t really understand the forces that drive the simultaneous emergence of multiple distinct genetic clusters of candida auris.
‘When we look at human pathogens, we tend to look at what’s immediate to us.
‘But we have to look at it more broadly. Everything is connected, the whole system. Fruit is just one example.’
Candida auris was first described in 2009 after being found in the ear canal of a 70-year-old Japanese lady. Auris is latin for ear, giving the fungus its name.
In 2011, it was reported as a cause of bloodstream infection in South Korea.
The fungus has since been spotted in Canada, Venezuela, Colombia, South Africa and India, as well as Spain, Norway, and Germany.
The US Centers for Disease Control and Prevention (CDC) considers the fungus a ‘serious global health threat’ and one of the five pathogens posing the greatest danger to humans worldwide.
In the US there have been 587 reported cases, mostly in New York, New Jersey and Illinois, leading candida auris to be put onto an ‘urgent threats’ list by the CDC.
Based on current information, 30–60 per cent of people with candida auris infections have died, according to the CDC.
But many of these people had other serious illnesses that also increased their risk of death.
British health chiefs issued guidance to protect against the fungus in 2017 amid fears it was spreading in hospitals ‘like wildfire’.
Advice included telling doctors to isolate any infected patients and ramp up hygiene measures.