Presence of HSP90 Gene in Amphotericin B Resistant Aspergillus Species Isolated from Iranian Immunocompromised Patients

Aspergillosis is an opportunistic infection caused by Aspergillus spp in immunocompromised patients. The role of HSP90 in Aspergillus drug resistance is still unknown. The aim of this study was to evaluate the correlation between the presence of HSP90 gene and polyene resistance in Aspergillus spp using PCR.
In this study, 32 Aspergillus strains were used, which were isolated from patients susceptible to aspergillosis through Bronchoalveolar lavage (BAL) and identified by conventional methods. The isolates were cultured on Sabouraud dextrose agar (SDA). Susceptibility testing against amphotericin B was conducted according CLSI standards (M38-A). Also, the presence of HSP90 gene was evaluated using PCR.
Of 32 Aspergillus strains used in this study, 16 (50%) isolates were identified as A. Flavus, 12 (37.5%) isolates as A. fumigatus, and 4 (12.5%) isolates as A. terreus. Among these species, 19 (59.37%) isolates were sensitive to amphotericin B whereas 13 (40.62%) were resistant. Moreover, there was a significant difference between the presence of HSP90 gene and resistance to amphotericin B in Aspergillus species.
The presence of HSP90 gene provides evidence that shows this gene may play important role in resistance to amphotericin B in Aspergillus isolates. Although numerous regulatory genes are involved in resistance mechanisms, they remaines to be more clarified.