Whole-Genome Sequencing, Phenotypic Characterization, and Antifungal Susceptibility Profiles of Three Aspergillus hortae Clinical Isolates from Colombia

The Aspergillus genus comprises fungi that are widely distributed in nature. The Terrei section is particularly important due to its functions in recycling organic matter. 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, three clinical A. hortae isolates from Colombia, initially identified as A. terreus, were characterised by micro and macro-morphological analysis at 26°C and 37°C. A bioinformatic pipeline was used for molecular typing, which included analysis of whole genome sequences for accurate species identification. Susceptibility assays were also conducted using the microdilution broth method (EUCAST). It was confirmed that this species is intrinsically resistant to Amphotericin B with a minimum inhibitory concentration (MIC) of 2-4 mg/L, and is also thermotolerant. We obtained the in vitro susceptibility profiles for three azole drugs (MIC, 0.25-1 mg/L). The three isolates showed phylogenetic divergence from the reference genome strain. 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.