Molecular Identification and Antifungal Susceptibility Testing of Fungal Strain Isolated from Sinusitis Infections

Abstract

Background: Fungal sinusitis is a sinus infection that results from filamentous and yeast-like fungi. Fungal sinusitis infections range from chronic to acute, all causing similar symptoms such as nasal congestion and sinus pain. Objectives: This study aimed to evaluate the drug susceptibility of fungal isolates collected from sinus infections. Methods: A total of 61 fungal strains with fungal sinusitis origin, including 50 isolates of Aspergillus spp and 11 isolates of Rhizopus spp were identified using DNA sequencing with beta-tubulin and ITS genes. Antifungal susceptibility to eight drugs (including amphotericin B, itraconazole, voriconazole, posaconazole, isavuconazole, caspofungin, luliconazole, and lanoconazole) was evaluated using CLSI-M38-A2 method. Results: Out of 61 isolates including 21 isolates of Aspergillus fumigatus, 16 isolates of Aspergillus flavus, 13 isolates of Aspergillus niger, and 11 isolates of Rhizopus arrhizus were identified by DNA sequencing. Luliconazole (MIC range: 0.032 - 0.125 and MIC50: 0.032 µg/mL) was the most active drug In vitro against Aspergillus spp., followed by lanoconazole (MIC range: 0.032 - 0.25 and MIC50: 0.064 µg/mL), posaconazole (MIC range: 0.25 - 0.5 and MIC50: 0.125 µg/mL), itraconazole (MIC range: 0.125 - 1 and MIC50: 0.25 µg/mL), caspofungin (MEC range: 0.125 - 1 and MEC50: 0.5 µg/mL), voriconazole (MIC range: 0.032 - 1 and MIC50: 0.5 µg/mL) , isavuconazole (MIC range: 0.5 - 4 and MIC50: 1 µg/mL) and amphotericin B (MIC range: 0.125 - 8 and MIC50: 1 mg/mL), in order of decreasing activity. The caspofungin, and voriconazole demonstrated poor In vitro activity against R. arrhizus isolates evaluated, followed by isavuconazole. Conclusions: In vitro antifungal susceptibility showed that luliconazole, lanoconazole, and posaconazole had good In vitro antifungal activity against all isolates. The azole agents exhibited better activity than polyene and echinocandin against Aspergillus spp and R. arrhizus. The correct diagnosis of the fungal causative agents along with antifungal susceptibility testing (AFST) is an effective in the management of patients with fungal sinusitis.