Black Aspergillus strains including, Aspergillus Niger and A. tubingensis, are the most common causes of otomycosis with worldwide distribution. Luliconazole, appears to harbor the best potential for in vitro activity against black Aspergillus strains.

The goal of a new study published in the Iranian Journal of Microbiology was to compare the in vitro activity of luliconazole to commonly used antifungals—against clinical and environmental strains of black Aspergillus.

Here, 67 strains—37 clinical and 30 environmental—of black Aspergillus were identified using morphological and molecular technique (β-Tubulin gene). Antifungal susceptibility test was applied according to CLSI M38 A2.

It was found that Aspergillus Niger was the common isolate specie, followed by A. tubingensis in both, clinical and environmental strains. The lowest minimum inhibitory concentration (MIC) range, MIC50, MIC90 and MICGM was attributed to luliconazole for clinical strains. The highest resistant rate was found with amphotericin B – for both, clinical (86.5%) and environmental (96.7%) strains, whereas 54.1% of clinical and 30% of environmental isolates were resistant to caspofungin. Meanwhile, clinical strains of Aspergillus were more sensitive to voriconazole (86.7%) than the environmental strains (70.3%). On the other hand, 83.8% of clinical and 70% of environmental isolates were resistant to posaconazole.

It was concluded that luliconazole is a potent antifungal for Aspergillus Nigri complex. The results indicated that the in vitro extremely antifungal efficacy against black Aspergillus strains of luliconazole, is different from those of other used antifungals.

Source: Iranian Journal of Microbiology. 2020, April, 1(6):510-519.