Molecular Detection of Azole-Resistant Aspergillus fumigatus Isolates Carrying TR₃₄/L98H Mutations in Soil Samples from the Critical Hospitals

Abstract—Purpose: Azole resistant Aspergillus fumigatus isolates is recognised as an emerging problem worldwide. The higher use of azole fungicides in agriculture are functionally related with the azole resistance. The mutations in cyp51A gene is the principal mechanism of resistance among A. fumigatus isolates. The present study was conducted with the aim of investigating the current status of the azole-resistant A. fumigatus isolates obtained from the hospital environment. Methods: A total of 120 soil samples were collected from two university hospitals in Tehran, Iran. A. fumigatus isolates were identified using DNA sequencing of the partial β‑tubulin gene. The in Institute document (CLSI) M38-A2 and resistance mechanisms were investigated with the use of cyp51A genome sequencing on the azole resistance isolates. Results: 29 (24%) isolates were identified as A. fumigatus, 16 of which were recognized as azole-resistant. Five azole-resistant A. fumigatus isolates harbored the TR₃₄/L98H allele, and the remaining had no mutation in the cyp51A gene. However, other point mutations, i.e., TR46/Y121F/T289A, F46Y, G54 W, Y121F, G138 C, M172 V, F219 C, M220I, D255E, T289F, G432 C, and G448S, were not detected in the cyp51A gene. Conclusions: This study is of public health concern and need to develop new classes, effective and safe fungicides in agriculture that inhibits cross-resistance development resistance in clinical practice.