The tale of two seas - the Black Sea and the Mediterranean Sea regarding clinically important fungi

Abstract

Seawater and freshwater of rivers or lakes and their surrounding sand or soil have been shown to harbour bacteria and fungi. Among these microorganisms, the fungi of clinical interest can impact human health in various ways, posing an important risk to public health. In this article, we will present data of a 2-year survey of fungal contamination of seawater and sand on multiple beaches from Romania and Israel, and discuss the possible effects of the various climatic factors with respect to the mycobiota found in the two sites: the Black Sea versus the Mediterranean Sea. The samples were collected quarterly in 2018 and 2021 from 6 Israeli and 20 Romanian coastal beaches and subsequently processed in the lab for evaluation of fungal burden and mycobiota diversity. Matrix-Assisted Laser Desorption/Ionization Time-Of-Flight Mass Spexctrometry (MALDI-TOF MS) and internally transcribed spacer sequencing were used for fungal identification. In Israel, the most common moulds isolated were the Aspergilli, both in sand and water. In Romania, dematiaceous fungi are predominant, followed by Penicillium isolates. The yeast genera isolated both in sand and seawater of Black and Mediterranean seas were Candida, Cryptococcus, Rhodotorula, Trichosporon, and Geotrichum. The study revealed that fungi are constantly contaminating the sand and seawater in both coastlines; there is a difference between mycobiota in Israeli and Romanian beaches mainly related to different climatic conditions; yeast contamination seems to be related with human activities and pollution episodes, especially during high season; many of the yeast and mould species have the potential to cause human disease, particularly in immunocompromised or debilitated individuals.