[Azole resistance in Aspergillus fumigatus in the Netherlands--increase due to environmental fungicides?].

The mould Aspergillus fumigatus may develop mechanisms that confer resistance to itraconazole, voriconazole and posaconazole. In the Netherlands a dominant resistance mechanism referred to as TR/L98H is found. In A. fumigatus isolates recovered from clinical samples in Dutch hospitals the prevalence of azole resistance varied between 0.8% and 9.4%. The TR/L98H resistance mechanism probably develops in our environment, as azoles are frequently used for crop protection and material preservation. It is likely that breathing in the resistant spores of these strains from the environment leads to clinical infection. More research is needed to understand the environmental route of resistance development and to enable effective measures to prevent this occurring. Azole resistance is associated with treatment failure. Of 8 patients with azole-resistant invasive aspergillosis 7 died within 12 weeks of diagnosis. Alternative treatment regimens might include lipid-formulation of amphotericin B or a combination of voriconazole and an echinocandin, but there is little data available to support these choices. Physicians who treat patients with Aspergillus diseases should be aware of the possibility of azole resistance, also in azole-naïve patients.