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Appearance of Environment-Linked Azole Resistance in the Aspergillus fumigatus Complex in New Zealand

Summary

Researchers in New Zealand have discovered that a dangerous fungus called Aspergillus fumigatus is developing resistance to commonly used antifungal medications. Unlike previous cases where the resistance came from medical treatment, this new resistance appears to come from environmental exposure, possibly through garden fungicides that people can buy at garden centers. The study found that people, especially lung transplant patients, may be acquiring these resistant fungal strains from their surroundings rather than from hospitals, highlighting the need for better monitoring of agricultural fungicide use.

Background

Until 2020, azole resistance in Aspergillus fumigatus complex isolates in New Zealand was due to cyp51A hot spot mutations. This report details the appearance of environment-linked tandem repeat (TR)-related azole resistance genotypes since 2021, which are strongly linked to acquisition of environmental strains exposed to fungicides containing azoles used in agriculture.

Objective

To characterize the emergence of TR-associated azole resistance in A. fumigatus complex isolates in New Zealand and identify the resistance mechanisms and potential sources of infection using whole genome sequencing and epidemiological analysis.

Results

From January 2021 to June 2024, 15 of 147 (10.2%) A. fumigatus complex isolates were resistant or non-wild-type for azoles. Genotyping detected hot spot mutations in four isolates and TR-associated resistance in nine. WGS of paired isolates showed non-wild-type isolates were distinct from their wild-type predecessors and from each other. No healthcare-acquired transmission was identified.

Conclusion

A. fumigatus sensu stricto isolates with TR-mutations linked to environmental resistance are now present in New Zealand. Those at risk of invasive A. fumigatus infection should receive advice to avoid high-risk exposures. Reintroducing monitoring of azole-containing fungicides in agriculture is recommended to address this emerging resistance threat.
  • Published in:Mycoses,
  • Study Type:Retrospective Review,
  • Source: 10.1111/myc.70104, PMID: 40857214
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