Caspian Sea Mycosands: The Variety and Abundance of Medically Important Fungi in Beach Sand and Water

Abstract

Samples from a total of 67 stations, distributed amongst 32 cities along the Caspian Sea coastline, were collected during the summer of 2021 on sunny days. The samples were collected from each station, including both dry/wet sand and shoreline water. The grown samples were primarily analyzed for the macro/microscopic morphologic features of the fungi. Moreover, identification by PCR-RFLP was performed for yeasts, dermatophytes, and Aspergillus sp. strains. Antifungal susceptibility tests were performed for probable-isolated Aspergillus and Candida sp. A total of 268 samples were collected, from which 181 (67.54%) isolates were recovered. Yeast-like fungi and potential pathogenic black fungi were detected in 12 (6.6%) and 20 (11%) of the sand (dry/wet) samples. Potential pathogenic hyaline fungi were identified in 136 (75.1%) samples, in which Aspergillus sp. was the predominant genus and was detected in 76/136 (47.8%) samples as follows: A. section Flavi n = 44/76 (57.9%), A. section Nigri n = 19/76 (25%), A. section Nidulantes n = 9/76 (11.8%), and A. section Fumigati n = 4/76 (5.3%). The most effective azole antifungal agent was different per section: in A. section Fumigati, PSZ; in Aspergillus section Nigri, ITZ and ISZ; in A. section Flavi, EFZ; and in A. section Nidulantes, ISZ. Candida isolates were susceptible to the antifungals tested.