The cdr1B efflux transporter is associated with non-cyp51a-mediated itraconazole resistance in Aspergillus fumigatus

ObjectivesRecent increases in triazole resistance in Aspergillus fumigatus have been attributed primarily to target site (cyp51A) mutations. A recent survey of resistant isolates in Manchester showed that >50% of resistant isolates had no mutation in cyp51A or its promoter. We investigated the mechanisms of resistance in clinical azole-resistant isolates without cyp51A mutations.