Introduction: Representatives of the genus Trichosporon are basidiomycetous yeast-like microorganisms that are widely distributed in nature. The genus Trichosporon includes species capable of causing both superficial and invasive infections associated with high mortality rates. A notable characteristic of the Trichosporon species is their resistance to many antifungal agents that are commonly used for the treatment of invasive fungal infections.
Materials and Methods: Trichosporon sp. were isolated from samples of the affected skin of a patient with a chronic infection. Identification was performed using MS (mass spectrometry).
The producer Streptomyces sp. strain SVP-71 was isolated from bentonite samples. The antifungal antibiotic was extracted from the culture fluid and biomass using butanol. Primary purification and metabolite separation were carried out using TLC. The obtained antibiotic was applied to sterile paper discs (14 µg per disc). Specific activity control was performed using discs with dried butanol.
The susceptibility of the clinical isolate to the obtained antibiotic was determined using the DDM, according to CLSI M44 guidelines. Caspofungin discs (5 mg, HiMedia), one of the most effective antifungal antibiotics, were used as a reference.
Results: Screening studies revealed the antagonistic activity of Streptomyces sp. strain SVP-71 against a wide range of yeast-like and filamentous fungi that are pathogenic to humans, including the emerging pathogen Candida auris. The disc diffusion method also confirmed the activity of secondary metabolites from Streptomyces sp. strain SVP-71 against the clinical isolate of Trichosporon sp., with growth inhibition zones reaching up to 20 mm. In contrast, echinocandin antibiotics (caspofungin) showed no specific activity against this microorganism.
Conclusions: The strain Streptomyces sp. SVP-71 demonstrates promise as a source of new antifungal agents, particularly for treating infections caused by fungi with natural resistance to standard antibiotics, such as echinocandins. This is of significant importance in the fight against mycoses that present as severe invasive infections.
