Azole-resistant Aspergillus fumigatus isolates carrying TR₃₄/L98H mutations in Taiwan

Cumulative evidence described the emergence and geographical expansion of azole-resistant A. fumigatus associated with azole treatment failure. To investigate the status of azole resistance in A. fumigatus in Taiwan, we studied 38 A. fumigatus clinical isolates cultivated from 31 patients at two teaching hospitals from 2011 to 2014. Three isolates obtained from respiratory samples of two azole-naïve patients with pulmonary aspergillosis were found to display multi-azole resistance and cross resistance to agricultural azole fungicides, and all carried TR₃₄/L98H mutations in cyp51A gene. The prevalence rates of azole resistance were 7.9% and 6.5% based on isolates and patients respectively. A phylogenetic analysis suggested genetic diversity of the TR₃₄/L98H isolates in Taiwan, including a unique genotype distinct from strains outside Taiwan. The result underlines the emergence of such isolates in Taiwan as well, emphasising the importance of further surveillance for azole-resistant A. fumigatus and implementation of strategies that prevent fungicide-driven resistance selection.