Azole-resistant Aspergillus fumigatus in Thailand

What is it about?

This study explored the prevalence, genetic diversity, and population structure of azole-resistant Aspergillus fumigatus (ARAf) at Walailak University in Southern Thailand. Three hundred samples were collected from dwellings and workplaces, screened for azole resistance, and tested for drug susceptibility. Molecular detection of alterations in the cyp51A gene and CSP1 typing were performed. Nucleotide polymorphism and haplotype diversity were calculated, and selective neutrality tests were performed. In total, 62 A. fumigatus isolates were identified, with 17 isolates displaying resistance to medical azoles. The prevalence of ARAf in the A. fumigatus isolates was 27.4%. Almost all azole-resistant isolates harbored an amino acid substitution in the hotspot region of the cyp51A gene, especially at or nearby the G54 residue that has been reported as a cause of azole resistance arising from long-term azole treatment. Moreover, some of the ARAf isolates harbored tandem repeats in the promoter region which have been reported as a cause of resistance arising from the use of azole fungicides in crop protection. Finally, selective neutrality testing also suggested an impact of natural selection on DNA diversity. Therefore, we hypothesize that the factors causing the high prevalence of ARAf in this area are both in vivo- and ex vivo-acquired resistance.

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Photo by Tim Goedhart on Unsplash

Photo by Tim Goedhart on Unsplash

Why is it important?

This is the first study to report the prevalence and population structure of azole-resistant Aspergillus fumigatus at Walailak University in Southern Thailand. This work is significant because aspergillosis can increase morbidity and mortality in patients with immunocompromised or immunocompetent conditions, such as chronic lung and myeloproliferative diseases, solid tumor, and neutropenia, and those undergoing corticosteroid treatments. Moreover, aspergillosis can increase morbidity and mortality in patients with respiratory infections such as influenza and COVID-19. Therefore, to develop control strategies, it is important to understand the origins and transmission patterns of the fungus.

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