Soil yeasts are an obligatory component of the microbial communities of undisturbed soils in natural ecosystems and of degraded soils in urban ecosystems. Changes in the taxonomic structure of yeast complexes in urban soils largely depend on the intensity of the prevailing anthropogenic stress.
Yeasts in urban soils near playgrounds are poorly studied. Yet the presence of opportunistic and pathogenic yeasts here can pose a serious threat to children whose immune systems are not yet sufficiently developed and to people with reduced immune status.
We examined topsoil from playgrounds in Moscow for the presence of opportunistic and pathogenic Candida species and evaluated the susceptibility profiles of isolates to antifungal drugs. Samples were collected in September 2022. CandiSelect 4 chromogenic medium was used for preliminary identification of yeasts of the Candida genus. Strains were identified based on the nucleotide sequence of the ITS region of the rDNA. Mueller-Hinton agar and the disk diffusion method were used to determine drug susceptibility.
The opportunistic yeast Candida parapsilosis was found in the soils near all playgrounds studied. Evaluation of the susceptibility profiles showed that, of the isolated strains, more than 45% were resistant to fluconazole, more than 20% were resistant to voriconazole, and slightly more than we 3% were resistant to amphotericin B. Thus, urban soils near playgrounds may be considered a reservoir for the maintenance and spread of yeast strains with potential health risks for children and adults.