One year prospective survey of azole resistance in Aspergillus fumigatus at a French cystic fibrosis reference centre: prevalence and mechanisms of resistance

Abstract

Background: Studies on Aspergillus fumigatus azole resistance in cystic fibrosis patients are scarce despite the fact that it is the most frequently isolated fungus from respiratory samples from these individuals.

Objectives: To evaluate resistance prevalence, investigate mechanisms of resistance and explore the relationship between resistant isolates by genotyping.

Methods: We conducted a prospective 1 year study (from 1 January to 31 December 2015), based on the investigation of up to five colonies per sample from cystic fibrosis patients.

Results: Twenty-three (6.5%) isolates among the 355 tested were resistant to at least one triazole drug, using the EUCAST reference method, leading to a prevalence of 6.8% (6/88 patients). Analysis of resistance mechanisms highlighted TR34/L98H (n = 10), TR46/Y121F/T289A (n = 1), WT cyp51A (n = 11) and F46Y/M172V/N248T/D255E/E427K (n = 1). No genotype was shared between patients.

Conclusions: This study showed a relatively stable resistance prevalence in comparison with the previous study conducted in 2010-11 (8%), although resistance mechanisms varied between the two studies.