P069 Caspian Sea Mycobiome: The variety and abundance of medically important fungi in beach sand and water
Authors: Moazeni Maryam , Hedayati Mohammad Taghi , Haghani Iman , Nabili Mojtaba , Kheshteh Maryam 
Published: September 2022

Poster session 1, September 21, 2022, 12:30 PM - 1:30 PM

 

Objectives

The Caspian Sea is considered the largest closed water body on the surface of the earth and its isolation has turned it into a very special ecosystem. Keeping the value of these highly appreciated areas for leisure and amusement is of extreme importance for the coastal communities. Regarding the importance of the issue, the present work reports on the distribution and the antifungal susceptibility profile of fungi collected from Caspian Sea beach sand and water.

Method

A total of 52 stations distributed within 32 cities along the Caspian Sea coastline in the North of Iran were evaluated. Samples were collected during the peak of summer 2021 (highest concentration of users) from June 1 to September 15 2021 on sunny days between 11 a.m. to 2 p.m. Four samples were collected from each station including dry sand collected from the middle of the dry sand section of the shore; wet sand comprising coastline areas sand and the shallow part (20 cm in depth) of seaboard ∼ 1m toward the seawater; and finally, water sample which was gathered from the shoreline. The grown samples were primarily analyzed according to the macro/microscopic morphologic features of the grown fungi. Also, molecular identification was performed for yeasts and Aspergillus sp. strains using the PCR-RFLP method by digesting beta-tubulin and ITS regions with Alw1 and Msp1 restriction enzymes, respectively. Antifungal Susceptibility tests were performed using CLSI M38, M60, and M59 for probable-isolated Aspergillus and Candida sp., respectively.

Results

From the 212 analyzed samples, 125 (58.9%) were positive for the fungal species comprising yeasts and yeast-like fungi (n = 18/14.4%) (C. albicans: n = 7, C. tropicalis: n = 2, other yeast species: n = 7/Trichosporon sp. n = 2), potential pathogenic black fungi (n = 17/13.6%) (Bipolaris sp. n = 2, Cladosporium sp. n = 3, other dematiaceous fungal species n = 12); and potential pathogenic hyaline fungi (n = 92/73.6%) (A. flavus/oryzae n = 34, Aspergillus section nigri n = 14, A. nidulans n = 5, A. fumigatus n = 2, Penicillium sp. n = 11, Fusarium sp. n = 3, Trichoderma sp. n = 18, Mucor sp. n = 3, Geotrichom sp. n = 2). A high variety of fungal species distribution was reported from wet sand samples rather than the other. Amongst, A. flavus/oryzae was the predominant species isolated from different type samples. Regarding M59, a rate of 9.0%, 3.6%, and 1.2% of Aspergillus section nigri, A. flavus/oryzae and A. fumigatus isolates were non-wild types against PSZ, respectively. In the case of ITZ, VRZ, and ISZ, only 1.2%, 1.2%, and 3.6% of total Aspergillus isolates were reported as non-wild type, respectively. All Candida isolates were wild type strains. According to GM values, EFZ and AMB were the most effective agents against yeasts, hyaline, and dematiaceous filamentous fungi.

Conclusion

Isolation of potentially pathogenic fungi especially those which have developed resistance against antifungals is of great concern for both beachgoer health and the coastal environment sanitation. Therefore, beach sand should be screened regularly for a variety of potentially pathogenic fungi which are considered to be harmful to human health, especially to whom they suffered from any kind of predisposing factor.