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.

Methods
Isolates were tested by broth micro-dilution. Clinical Laboratory Standards Institute criteria were used to define wild type (WT) and non-wild type (non-WT) isolates, which were identified by ß-tubulin gene sequencing and had their cyp51A genotype for azole resistance determined. Whole genome sequencing (WGS) was applied to two patient pairs of sequential WT and non-WT isolates.

Results
From January 2021 to June 2024, 15 of 147 (10.2%) A. fumigatus complex isolates were resistant or non-WT for one or more azole agents. Genotyping detected hot spot mutations in four and TR-associated resistance in nine. No mutations were detected in two isolates. Four of the five TR46 mutations were TR46/Y121F/T289A. Three of the four TR34 mutations were different. WGS of the paired isolates showed that the non-WT isolates were distinct. Azole-containing fungicides are available for home use from garden centres. Patients with TR-associated resistance did not have any obvious exposure to azole-containing fungicides. There was no evidence for healthcare-acquired transmission.

Conclusions
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 is recommended.