Objectives: Cryptococcus neoformans is a basidiomycetous encapsulated yeast that can cause life-threatening infections in immunosuppressed humans and animals. C. neoformans infections are considered to be acquired via inhalation of aerosolized particles from the environment. Avian guano, decaying tree hollows, and soil are known environmental niches. In recent years, different trees, such as Eucalyptus camaldulensis, Tamarix hispida, Platanus orientalis, and Punica granatum, have been reported to have C. neoformans colonies in different woody environmental regions of Anatolia, Turkey. In this study, a new C. neoformans colonization niche has been presented.
Methods: In this study, the colonization screening of C. neoformans on chestnut trees (Castanea spp.) from the Aydın-Ödemiş-Denizli geographical area is presented. This area consists of mountainous terrain between the fertile plain formed by two major rivers. From this area, 214 chestnut trees (Castanea spp.) that had deep fissures (Fig.1) or trunk hollows were screened during the mid-summer, 2017 (Table 1). A swabbing technique was used, and all samples were cultured on Staib agar medium containing 0.5% biphenyl and 0.4% chloramphenicol. 
Results: Candidate yeasts were tested for the presence of Cryptococcus by conventional methods and canavanine-glycine-bromothymol agar reactions. Only one (0.47%) strain of C. neoformans was isolated from all 214 screened trees (Figs. 2 and 3). This strain was confirmed by ITS 1-4 sequencing. We determined the mating type and serotypes by PCR analysis of the STE20 genes using STE20 (Aa), STE20 (A), STE20 (Da), and STE20 (D) primers. The serotype A MAT mating type was observed (Fig. 4). 
Conclusion: Here, the first C. neoformans isolate from a chestnut tree (Castanea sativa) is presented. Further studies of distribution of human pathogenic Cryptococcus in our country will be helpful in determining risk areas that threaten mammalian health.

Isolation of Cryptococcus neoformans from a chestnut tree (Castanea sativa), Denizli, Turkey