Whole-genome sequencing, phenotypic characterization, and antifungal susceptibility profiles of three Aspergillus hortae clinical isolates from Colombia.

Abstract

The Aspergillus genus comprises fungi that are widely distributed in nature. Several Aspergillus sections are important for recycling organic matter; while the Fumigati section is classically associated with compost, the Terrei section also plays a relevant role in this process. Aspergillus hortae is a species from this section that has been isolated from clinical samples, but its role as a pathogenic agent is unclear. In this study, we analysed three clinical isolates of A. hortae from Colombia, initially misidentified as A. terreus. Morphological characterization at 26 °C and 37 °C confirmed its thermotolerant nature. Whole-genome sequencing enabled accurate species identification and revealed phylogenetic divergence from the reference genome. Antifungal susceptibility testing (EUCAST broth microdilution) showed intrinsic resistance to amphotericin B (MIC 2-4 mg/L) and susceptibility to azoles (MIC 0.25-1 mg/L). A mutation (M769K) in the MelA ortholog of a hypopigmented isolate, which had the lowest MIC value for AmB (2 mg/L), was identified. This study presents the morphological characterization, molecular typing through whole-genome analysis and identification of susceptibility profiles to azoles and amphotericin B of three clinical isolates of A. hortae from Colombia.