Species assignment and antifungal susceptibilities of black aspergilli recovered from otomycosis cases in Iran

Abstract

Black aspergilli are among the main causative agents of otomycosis worldwide. In this study, the species assignment of black aspergilli isolated from otomycosis cases in Iran was carried out using sequence analysis of part of the calmodulin gene. The results indicate that Aspergillus niger is not the only black Aspergillus species involved in otomycosis cases in Iran: Aspergillus awamori and Aspergillus tubingensis are also able to cause ear infections. Antifungal susceptibility tests were carried out against five antifungal drugs including amphotericin B, fluconazole, itraconazole, ketoconazole and terbinafine. All isolates were highly susceptible to terbinafine, while they exhibited moderate susceptibilities against amphotericin B, fluconazole and ketoconazole. Aspergillus niger and A. awamori were found to have higher minimal inhibitory concentrations for azoles than A. tubingensis, in accordance with previous findings.

Identification and Susceptibility of Aspergillus Section Nigri in China: Prevalence of Species and Paradoxical Growth in Response to Echinocandins

“…The intraspecific and interspecific differences in the antifungal susceptibilities of Aspergillus section Nigri from previous studies were inconsistent (7)(8)(9)(10)(11)(12)(13), primarily for the azoles and amphotericin B. Our study also observed the above differences among voriconazole, terbinafine, and amphotericin B, but all the MICs were low for both species.…”

“…In recent years, sequence-based molecular methods have been used successfully for species identification in this group, particularly methods using the calmodulin gene, which can distinguish all species within section Nigri (4-6). Molecular studies indicated that several species in addition to A. niger were able to cause human infections; different regions had different species of pathogenic black Aspergillus, and A. niger and Aspergillus tubingensis were the most frequently identified pathogens in previous studies (2,(7)(8)(9)(10)(11)(12)(13)(14). Additionally, it is worth noting in a clinical context that azoles exhibited different activity against the two species and that isolates from different geographical regions exhibited remarkable differences in susceptibility to azoles and amphotericin B (1-13, 15).…”

Diagnosis and treatment of otomycosis in southern China

“…Aspergillus is the most common fungus cultured from otomycosis patients, consisting of 60%‐90% of all pathogens reported in several studies from different countries. Candida is the second most, consisting of nearly 10%‐40% . In our study, Aspergillus species were isolated in 84.3% of cases (75/89), and Candida species were found in 8.9% (8/89).…”

Aspergillus Luchuensis, an Industrially Important Black Aspergillus in East Asia

“…In addition, this species was also identified in various otomycosis cases both in Iran and Hungary [34], [35]. Although the name A. awamori was used taxonomically correctly by Perrone et al [15], this currently used name is misleading, as this species is rarely identified in awamori fermentation processes, where mostly A. niger and A. luchuensis could be isolated [11].…”