A study using citizen science data has shown people across the UK are being widely exposed to drug-resistant airborne fungal spores that cause potentially fatal lung infections for those with weakened immune systems.
Almost 500 members of the public responded to an appeal on social media by the UK Centre for Ecology & Hydrology (UKCEH), providing air samples for the study after exposing air samplers on the outdoor windowsills of their homes or workplaces. Around 1,900 samples were sent back, making it the largest study of the environmental resistance of Aspergillus fumigatus, the main fungal pathogen that causes aspergillosis.
Aspergillosis is rare in healthy people but can occur in those with a chronic lung condition, a weakened immune system or have previously contracted tuberculosis (TB), severe flu or coronavirus infection.
Aspergillosis takes multiple forms: from a severe allergy to inhaled spores, to chronic colonisation of the lungs by mould spores, to potentially fatal systemic infection if spores spread from the lungs into the bloodstream and other organs.
Scientists believe the widespread use of agricultural fungicides, which are based on the same chemistry as the clinical drugs to treat aspergillosis, is causing the evolution of environmental resistance to these medications.
Half the air samples collected grew Aspergillus, totalling 2,366 colonies of the fungi. A selection of agricultural and medical anti-fungal drugs were then applied to these colonies. Some 5% of spores were found to be resistant to at least one of the five anti-fungal drugs tested and, of these, 14% were resistant to all four medicines used to treat aspergillosis.
The scientists carrying out the study, published in the journal Science Advances, estimated each individual in the UK will have a cumulative exposure of 21 days a year to drug-resistant Aspergillus spores.
Dr Jennifer Shelton, now a molecular ecologist at UKCEH, led the study after asking the public to collect air samples on the northern hemisphere seasonal equinoxes and solstices in June, September and December 2018 and March 2019.
Dr Shelton explained: “Air sampling for Aspergillus fumigatus has not been done on this scale before. The involvement of citizen scientists allowed us to collect a huge number of samples from a single timepoint – which is not achievable by a research group alone – and to estimate background levels of drug-resistant spores in UK air.
“Once we understand the scale of the problem we can begin to mitigate it and help those most at risk of developing aspergillosis to reduce their exposures."
Professor Mat Fisher of Imperial College London, a co-author of the study, added: "Fungal infections are often neglected, yet cause a global public health burden. The worsening problem of resistance to antifungal drugs needs urgent attention if we are to continue to protect those that are at risk from fungal disease"
The research also involved the University of Nottingham, Public Health England, the University of Exeter and Radboud University Medical Centre in Nijmegen. It was funded by the Natural Environment Research Council and the UK Medical Research Council, which are part of UK Research and Innovation.
Shelton et al. 2023. Citizen science reveals landscape-scale exposures to multiazole-resistant Aspergillus fumigatus bioaerosols. Science Advances. DOI: 10.1126/sciadv.adh8839