First report of increased amphotericin B resistance in Coniochaeta polymorpha isolates from Rangifer tarandus platyrhynchus droppings in Spitsbergen

The study examines Coniochaeta polymorpha strains isolated from reindeer droppings in Spitsbergen, focusing on their growth characteristics, antifungal resistance profiles, and enzymatic activities. Notably, all strains exhibited high resistance to fluconazole (MIC, 256 μg/mL), suggesting an inherent trait. Amphotericin B sensitivity varied, with some strains showing high MIC values, indicating emerging resistance. This occurrence is notable in polar ecosystems, which are minimally impacted by human activity. Moreover, enzymatic assays revealed significant proteolytic and esterase activities, as well as partial α-hemolysis, suggesting enhanced virulence potential in C. polymorpha. Phylogenetic analysis confirmed genetic diversity among six isolated strains, highlighting distinct clades within the species. These findings contribute to understanding C. polymorpha pathogenic potential and ecological versatility.