Prévalence et mécanismes de résistance aux triazolés des espèces d’Aspergillus section Fumigati
Aspergillus fumigatus is the principal agent of invasive aspergillosis. A growing number of A. fumigatus isolates in Europe are found to be resistant to the triazoles, the primary antifungals used in treatment. Moreover, many “cryptic” Aspergillus species, morphologically and genetically similar to A. fumigatus, are misidentified in the clinical diagnostic laboratory, and several of these “cryptic” species are intrinsically resistant to the triazoles. Resistance mechanisms of “cryptic” Aspergillus section Fumigati species are not well known. In the present retrospective study, conducted on a collection of Aspergillus clinical isolates from Maisonneuve-Rosemont Hospital, the prevalence of the « cryptic » species among all Aspergillus section Fumigati was 1.4%, and 1.0% of all isolates in the collection were azole-resistant. Analysis of resistance mechanisms produced evidence for efflux pump-mediated resistance in Aspergillus turcosus and A. fumigatus isolates, in contrast to the triazole-resistant Aspergillus thermomutatus and Aspergillus lentulus species which display resistance likely mediated by mutations in the cyp51a gene.
Aspergillus section Fumigati cyp51a triazoles resistance cryptic species