GoKawiilTrials of drugs to fight deadly resistant infections are advancing, but they might fall victim to overuse of agricultural fungicides just like their predecessors.
Fungicides are often sprayed onto crops in large quantities to prevent fungal diseases occurring later in the season.Credit: Dave Thurber/Design Pics Editorial/Universal Images Group via Getty
Not for nothing are fungi often described as the ‘hidden kingdom’. Many exist mainly or entirely underground, and only around 5% of the world’s fungal species are thought to have been discovered so far.
Although the problem of bacteria becoming resistant to the drugs used to defeat them has long attracted attention, its fungal parallel has flown mostly under the radar. “Very little research is done on human fungal infections compared to other types of infections,” says Matthew Fisher, a fungal epidemiologist at Imperial College London. He is one of a number of researchers who think that this urgently needs to change. “When it comes to antifungal resistance in the clinic, the situation is deteriorating alarmingly,” he says.
Nature Outlook: Antimicrobial resistance
Common fungal infections, such as thrush and athlete’s foot, are merely a source of discomfort. Most people can easily repel even the deadliest fungal pathogen, Aspergillus fumigatus, which is abundant in decaying plant matter and inhaled daily by most people without them noticing. But the same cannot be said for individuals with weakened immune defences.
For people with chronic lung diseases or HIV, or who are taking corticosteroids or other immunosuppressive drugs, a fungal infection can have serious consequences. David Denning, a medical mycologist at the University of Manchester, UK, estimates that more than 2.5 million deaths worldwide are caused by fungal infections annually, and that fungi contribute to another 1.2 million deaths ascribed to other conditions. Most deaths from fungal infections are caused by A. fumigatus — either in the lungs or, in the case of invasive aspergillosis, elsewhere in the body.
The main treatment is with drugs called azoles, resistance to which is a growing problem. In Dutch hospitals, for example, azole resistance in A. fumigatus samples obtained from patients increased from 8% in 2013 to 15% in 20181. It has also been found in 14% of A. fumigatus samples taken from soil in UK gardens2, and in around 80% of greenhouse soil samples in China3.
Expanding problem
Aspergillus fumigatus is not the only fungal pathogen that is gaining resistance. Since it was discovered in Japan in 2009, Candida auris has spread to more than 60 countries and is rapidly becoming resistant to treatment. It is “a quiet pandemic”, says Fisher.
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