Tebuconazole induces triazole-resistance in Aspergillus fumigatus in liquid medium and soil.

Aspergillus fumigatus is the mainly leading cause of invasive aspergillosis associated with significant morbidity and mortality in immunocompromised patients. However, triazole resistance in A. fumigatus has increased dramatically throughout the world nowadays. The emergence of triazole resistance has aroused growing concern. This research was conducted to assess if the resistance in A. fumigatus and its associated mutations in the cpy51A gene could be induced during its exposure to tebuconazole in liquid medium and in soil. The results indicated that the resistance in A. fumigatus with mutations of TR46/Y121F/T289A could be induced by tebuconazole in liquid medium. Nine resistant strains without any mutation in cyp51A were isolated in soil treated with tebuconazole at levels of 0.5-5.0 mg kg-1 after incubation for 120 d. The two (HI-30 and HI-36) of the nine resistant isolates were caused by overexpression of AtrF, AfuMDR1, cyp51A and cyp51B and hereditary stability. This strongly implies that conventional application of tebuconazole for plant protection will cause resistance of A. fumigatus to triazole medicals in agricultural soils.